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Lab 3: Newton’s Laws Case Assignment
Lab 3: Newton’s Laws Case Assignment
Order ID 53563633773 Type Essay Writer Level Masters Style APA Sources/References 4 Perfect Number of Pages to Order 5-10 Pages
Description/Paper Instructions
Lab 3: Newton’s Laws Case Assignment
Please submit the table data and answers for this experiment on the Word document provided to you. Table 1: Mo on Data for Experiment 2
Trial M1 M2 Δd of M2 Time (s) Accelera on
Procedure 1
1
2
3
4
5
Average
Procedure 2
1
2
3
4
5
Average
Hint: You need to rearrange the formula d = 1/2 at 2 to calculate the accelera on. In this equa on,
d = distance, a = accelera on, and t = me.
Example: Suppose you set up an Atwood Machine. The M2 weight accelerates downward a distance of 1.30 me‐ ters in 1.50 seconds. What was the accelera on rate? Given: d = 1.30 meters t = 1.50 seconds The goal is to rearrange the formula to end with “a” by itself on one side of the equa on. To do this… 1. Set up your equa on, and square the value for t; 1.30 meters =
1 /2 · (a · (1.50 seconds)
2 )
Remove the “ 1 /2” by mul plying each side of the equa on by 2;
- 1.30 meters = 1 /2 · (a · 2.25 seconds) · (2)
- Remove the 2.25 seconds by dividing each side of the equa on by 2.25 seconds; 2.60 meters/2.25 seconds = a Answer: The accelera on for M2 = 1.15 meters per second.
47
Lab 3: Newton’s Laws
Ques ons 1. When you give one set of washers a downward push, does it move as easily as the other set? Does
it stop before it reaches the floor. How do you explain this behavior?
Draw a FBD for M1 and M2 in each procedure (Procedure 1 and Procedure 2). Draw force arrows for
the force due to gravity ac ng on both masses (Fg1 and Fg2) and the force of tension (FT). Also draw
arrows indica on the direc on of accelera on, a.
Experiment 3: Newton’s Third Law
Procedure 1. Tie one end of the fishing line to a chair. Space the second chair about 10 feet away. 2. String the other end of the fishing line through the straw. 3. Tie the loose end of the fishing line to the second chair. 4. Inflate a balloon. Hold it closed with your fingers, and tape it to the straw. 5. Slide the straw/balloon back so that the mouth of the balloon is facing the nearest chair. 6. Let go of the balloon and observe what happens.
Materials Fishing line Balloon Plas c straw Masking tape 2 Chairs* *You must provide
48
Lab 3: Newton’s Laws
Ques ons Please submit your answers for this experiment on the Word document provided to you.
Explain what caused the balloon to move in terms of Newton’s Third Law.
What is the force pair in this experiment? Draw a Free Body Diagram (FBD) to represent the (unbalanced) forces on the balloon/straw combina on.
Add some mass to the straw by taping some metal washers to the bo om and repeat the experi‐ ment. How does this change the mo on of the assembly? How does this change the FBD?
If the recoil of the rifle has the same magnitude force on the shooter as rifle has on the bullet, why does the shooter not fly backwards with a high velocity?
Lab 4: Acids & Bases
51
Lab 4: Acids & Bases
Introduc on
Have you ever had a drink of orange juice a er brushing your teeth?
What do you taste when you brush your teeth and drink orange juice a erwards? Yuck! It leaves a really bad taste in your mouth. But why? Orange juice and toothpaste by them‐ selves taste good. The terrible taste is the result of an acid/base reac on that occurs in your mouth. Orange juice is a weak acid and the toothpaste is a weak base. When they are placed together they neutralize each other and produce a product that is unpleasant to taste. In this lab we will discover how to dis nguish between acids and bases.
Two very important classes of compounds are acids and bases. But what exactly makes them different? Acids and bases have physical and chemical differences that you can ob‐ serve and test. According to the Arrhenius defini on, acids ionize in water to produce a hydronium ion (H3O
+ ), and bases dissociate in water to produce hydroxide ion (OH
‐ ).
Physical differences between acids and bases can be detected by the senses, including taste and touch. Acids have a sour or tart taste and can produce a s nging sensa on to broken skin. For example, if you have ever tasted a lemon, it can o en result in a sour face. Bases have a bi er taste and a slippery feel. Soap and many cleaning products are bases. Have you accidentally tasted soap or had it slip out of your hands?
Reac ons with acids and bases vary depending on the par cular reactants, and acids and bases each react differently with other substances. For example, bases do not react with most metals, but acids will react readily with certain metals to pro‐ duce hydrogen gas and an ionic compound—which is referred to as a salt. An example of this type of reac on occurs when magnesium metal reacts with hydrochloric acid. In this reac on, magnesium chloride (a salt) and hydrogen gas are formed.
Mg (s) + 2 HCl (aq) → MgCl2 (aq) + H2(g)
metal + acid → a salt + hydrogen gas
Acids may also react with a carbonate or bicarbonate to form carbon dioxide gas and water. The general reac on equa on for a reac on between an acid and a carbonate can be represented in this manner:
CO3 2-
(aq) + 2 H3O +
(aq) → CO2 (g) + 3 H2O (l)
carbonate + acid → carbon dioxide + water
The general equa on for a reac on between an acid and a bicarbonate is similar and can be represented in this manner:
Figure 1: Orange juice has a pH of around 3.5. Dairy milk, by comparison, is much less acid‐ ic, with a pH of around 6.5.
Concepts to explore: · Understand the proper es and reac ons of acids and bases · Relate these proper es to common household products
52
Lab 4: Acids & Bases
HCO3 –
(aq) + H3O +
(aq) → CO2 (g) + 2 H2O (l)
Acids and bases can also react with each other. In this case, the two opposites cancel each other out so that the product formed has neither acidic nor basic (also called alkaline) proper es. This type of reac on is called a neutraliza on reac on. The general equa on for the reac on between an acid and a base is represented in this manner:
H3O + + OH – → 2 H2O
An example of a neutraliza on reac on is when an aqueous solu on of HCl, a strong acid, is mixed with an aqueous solu on of NaOH, a strong base. HCl, when dissolved in water, forms H3O
+ and Cl
‐ .
NaOH in water forms Na
+ and OH
‐ . When
the two solu ons are mixed together the products are water and common table salt (NaCl). Neither water nor table salt has acid or base proper es. Generally this reac on is wri en without the water solvent shown as a reactant:
HCl + NaOH → H2O + NaCl
There is another group of acids called organic acids. Ace c acid found in vinegar and citric acid found in citrus fruit are examples of organic acids. These acids are all much weaker than HCl. Organic acids have at least one –CO2H group in their molecular formula. When a base is added, the –H of the –CO2H group is replaced just like the –H in HCl. In this lab you will use citric acid as the acid and sodium bicarbonate as the base. Citric acid has three –CO2H groups and only each of the H’s on these groups react with a sodium bicarbonate. The other H’s in the formula do not react. This reac on can be represented in this manner:
HOC(CO2H)(CH2CO2H)2 + 3 NaHCO3 → HOC(CO2 ‐ Na
+ )(CH2CO2
‐ Na
+ )2 + 3 CO2 + 3 H2O
Acids and bases are measured on a scale called pH. The pH of a substance is defined as the nega ve log of its hydronium ion concentra on. An aqueous (water) solu on that has a lot of hydronium ions but very few hy‐ droxide ions is considered to be very acidic, while a solu on that contains many hydroxide ions but very few hydronium ions is considered to be very basic.
pH = ‐ log [H3O + ]
pH values range from less than 1 to 14, and are measured on a logarithmic scale (equa on above). This means that a substance with a pH of 2 is 10‐ mes (10
1 ) more acidic than a substance with a pH of 3. Similarly, a pH of
7 is 100‐ mes (10 2 )more basic than a pH of 5. This scale lets us quickly tell if something is very acidic, a li le
bicarbonate + acid → carbon dioxide + water
Table 1: Approximate pH of various common foods.
Food pH Range
Lime 1.8 ‐ 2.0
So Drinks 2.0 ‐ 4.0
Apple 3.3 ‐ 3.9
Tomato 4.3 ‐ 4.9
Cheese 4.8 ‐ 6.4
Potato 5.6 ‐ 6.0
Drinking Water 6.5 ‐ 8.0
Tea 7.2
Eggs 7.6 ‐ 8.0
Acid + Base → Water
53
Lab 4: Acids & Bases
acidic, neutral (neither acidic nor basic), a li le basic, or very basic. A pH of 1 is highly acidic, a pH of 14 is highly basic, and a pH of 7 is neutral.
pH indicators, which change color under a certain pH level, can be used to determine whether a solu on is acidic or basic. Litmus paper is made by coa ng a piece of paper with litmus, which changes color at around a pH of 7. Either red or blue litmus paper can be purchased depending on the experimental needs. Blue lit‐ mus paper remains blue when dipped in a base, but turns red when dipped in an acid, while red litmus paper stays red when dipped in an acid, but turns blue when in contact with a base.
A more precise way to determine acidity or basicity is with pH paper. When a substance is placed on pH pa‐ per a color appears, and this color can be matched to a color chart that shows a wide range of pH values. In this way, pH paper allows us to determine to what degree a substance is acidic or basic and can provide an approximate pH value.
Pre‐lab Ques ons
What is a neutraliza on reac on?
Hydrochloric acid (HCl) is a strong acid. About what pH would you expect it to be?
- Sodium hydroxide (NaOH) is a strong base. About what pH would you expect it to be?
54
Lab 4: Acids & Bases
Experiment: Acidity of Common Household Products
In this experiment, we will observe the neutraliza on of acids and bases using grape juice as an indicator. We will also test common household products for their acidity or alkalinity.
Procedure
Part 1: Acid‐Base Neutraliza on
Label three test tubes 1, 2, and Standard.
Prepare 50 mL of a 10% grape juice solu on by first pouring 5 mL of grape Juice into a 100 mL graduated cylinder. Add dis lled water un l the total volume of liquid is 50 mL. Mix well by s rring the solu on with a s rring rod.
Pour 10 mL of the dilute grape juice solu on into each test tube.
Note the color of the juice in the test tube labeled Standard in Table 2.
Using a pipe e, add 15 drops of saturated citric acid solu on into test tube 1. Record your observa ons concerning the color change in Ta‐ ble 2 of the Data sec on. Use the juice in the test tube labeled Standard for comparison.
Using a pipe e, add 15 drops of saturated sodium bicarbonate solu on into test tube 2. Record your observa ons concerning the color change in Table 2 of the Data sec on. Use the juice in the test tube labeled Standard for comparison.
Use pH paper to determine the pH of the solu on in each of the 3 test tubes. Record the pH val‐ ues in Table 2.
Using a pipe e, add drops of saturated sodium bicarbonate solu on to test tube 1 un l it re‐ turns to its original color. Record your observa ons in Table 3.
Materials Safety Equipment: Safety goggles, gloves Vinegar Household ammonia **Grape Juice 3 test tubes pH strips Saturated citric acid solu on (60% Test tube rack Neutral litmus paper
Saturated sodium bicarbonate solu‐ on (15%)
(2) 50 mL beakers Tomato juice Sodium bicarbonate 12‐well plate Powdered milk Lemon juice 10 Droppers (pipe es) Baking soda Dishwashing liquid
S rring rod 100 mL Graduated cylinder *Dis lled water
*You must provide **Used in the next lab— refrigerate a er opening
HINT: If the grape juice
is not dilute enough or
the base is not as
strong as needed, you
may con nue adding
drops of base.
55
Lab 4: Acids & Bases
Using a pipe e, add drops of saturated citric acid solu on to test tube 2 un l it returns to its original col‐ or. Record your observa ons in Table 3.
Use pH paper to test the pH of the three solu ons. Record the pH values in Table 3.
Part 2: Tes ng acidity and basicity of common household products
Use the pipe es to place into different wells of your 12‐well plate a couple of drops of each of the fol‐ lowing items: tomato juice, household ammonia, milk (mix powdered milk with 50mL water un l dis‐ solved), vinegar, lemon juice, and diluted dishwashing liquid (mix 1mL dishwashing liquid with 5mL wa‐ ter). Be sure to label or write down where each item is located in the 12‐well plate. CAUTION: Do not contaminate the items being tested. Be sure to use only a clean pipe e for each item.
Guess the pH of each of the items before you find the experimental value and record your guess in Table 4.
Test each item with litmus paper and pH paper. Record your results in Table 4.
To clean up rinse all chemicals into a waste beaker. Neutralize the waste to a pH between 4 and 8 using either baking soda or vinegar. Wash the waste solu on down the drain.
Data
Please submit your table data and answers for this experiment on the Word document provided to you.
Table 2: Acid‐Base Neutraliza on for Part 1, Steps 5 & 6 Table 3: Acid‐Base Neutraliza on for Part 1, Steps 8 & 9
Test tube 1 Test tube 2 Standard
Step 1 Add acid Add base Neutral
Color
pH value
Test tube 1 Test tube 2 Standard
Step 1 Add base Add acid Neutral
Color
pH value
Table 4: Acidity and basicity tes ng for household products data
Product Hypothesized pH Color of Litmus
Paper Color of pH Paper Actual pH
56
Lab 4: Acids & Bases
Ques ons
Why did the grape juice change color when an acid or base was added?
You added a base, sodium bicarbonate, to test tube 1 that contained citric acid and an acid to test tube 2 that contained base. Why did the grape juice return to its original color?
Name two acids and two bases you o en use.
Lab 5: Chemical Processes
59
Lab 5: Chemical Processes
Introduc on
Have you ever needed to place a cold pack on a sprained muscle?
It’s the final seconds of the community league champion‐ ship basketball game, and your team is behind by one point. One of your team’s players takes a shot and scores. The game is over, and your team won! But something is wrong: the player is si ng on the floor, and appears to be in a lot of pain. The coach quickly brings a cold pack to the player, squeezes it, and places it on the swelling ankle. The bag immediately becomes cold—but how?
Though we o en use them interchangeably, heat and tem‐ perature have different defini ons—though they are close‐ ly related in the study of thermodynamics. Heat is the transfer of energy from one object to another due to a difference in temperature. Temperature, on the other hand, describes how much energy the atoms and molecules in a sub‐ stance have. This energy, o en called internal energy, describes how quickly the atoms or molecules in a substance move or vibrate around. When an object gains heat its molecules vibrate with more energy, which we can sense or measure as an increase in temperature. When you touch a hot object, it feels hot because a heat moves from the hot object (higher energy) to your skin (lower energy). Similarly, an object feels cold when heat is lost by your hand and gained by the cold object. Heat always transfers in the direc on of high temperature to low temperature—high energy to low energy.
Both physical processes and chemical reac ons can release or absorb energy in the form of heat. When a reac on or phys‐ ical change gives off energy it is called an exothermic process. To remember exothermic, think of ‘exi ng’ as in leaving or going out. An endothermic process does just the opposite—it takes in energy from its surroundings. The generalized chemical equa ons for exothermic and endothermic reac ons are:
The direc on energy moves determines whether the process is considered endothermic or exothermic, and tells you how the temperature of a system changes. In an endothermic reac on or physical change, energy is absorbed and the overall temperature of the system decreases. Some examples of endothermic processes include the mel ng of water in a so drink or the evapora on of a liquid. Similarly, an endothermic reac on takes in energy for chemical changes to occur. One example is what occurs in an instant cold pack like the ones used to decrease the swelling caused from a sports injury. The‐
exothermic:
endothermic:
reactants → products + energy
reactants + energy → products
Figure 1: The combus on of fuel, such as wood or coal, is a com‐ mon example of an exothermic reac on. Under the right condi‐ ons (usually the applica on of enough heat), a chemical reac‐ on occurs between wood and the oxygen in air. Fire is the re‐
Concepts to explore: · Understand the difference between endothermic and exothermic
processes
- Understand the concept of enthalpy
60
Lab 5: Chemical Processes
se types of cold packs u lize the chemical process of ammonium nitrate (NH4NO3 ) dissolving in water. The ammonium nitrate needs to absorb heat from the surrounding water to dissolve, so the overall temperature of the mixture de‐ creases as the reac on occurs.
In contrast, energy is released in an exothermic process. An example of an exothermic reac on is what occurs in com‐ mon hand warmers. The increase in temperature is the result of the chemical reac on of rus ng iron:
4 Fe(s) + 3 O2(g) ® 2 Fe2O3(s) + energy
Iron usually rusts fairly slowly so that any heat transfer is not easily no ced. In the case of hand warmers, common table salt is added to iron filings as a catalyst to speed up the rate of the reac on. Hand warmers also have a permea‐ ble plas c bag that regulates the flow of air into the bag, which allows just the right amount of oxygen in so that the desired temperature is maintained for a long period of me. Other ingredients that are found in hand warmers include a cellulose filler, carbon to disperse the heat, and vermiculite to insulate and retain the heat.
Enthalpy is a quan ty of energy contained in a chemical process. In the cases we will be dealing with, the energy re‐ leased or absorbed in a reac on is in the form of heat. Enthalpy by itself does not have an absolute quan ty, but changes in enthalpy can be observed and recorded. For example, if you s ck your finger into a glass of cold tap water, it probably feels pre y cold. However, a er being outside on a freezing winter day for a long period of me, the same glass of water might actually feel warm to touch. It would be difficult to measure the absolute quan ty of energy in the water in either case, but it is rela vely easy to no ce the movement of energy from one object to another. In exother‐ mic reac ons, heat energy is released and the change in enthalpy is nega ve, while in endothermic reac ons, energy is absorbed and the change in enthalpy is posi ve.
Pre‐lab Ques ons
Define enthalpy:
What is the rela onship between the enthalpy of a reac on and its classifica on as endothermic or exo‐ thermic?
With instant hot compresses, calcium chloride dissolves in water and the temperature of the mixture in‐ creases. Is this an endothermic or exothermic process?
Note: the energy term on the right side shows that the reac on is exothermic, but is not required.
61
Lab 5: Chemical Processes
Experiment: Cold Packs vs. Hand Warmers
In this lab you will observe the temperature changes for cold packs and hand warmers. Since temperature is defined as the average kine c energy of the molecules, changes in temperature indicate changes in energy. You will use simply a Styrofoam cup as a calorimeter to capture the energy. The customary lid will not be placed on the cup since ample oxy‐ gen from the air is needed for the hand warmer ingredients to react within a reasonable amount of me.
Procedure
Part 1: Cold Pack
Measure 10 mL of dis lled water into a 10 mL graduated cylinder.
Place about 1/4 of the ammonium nitrate crystals found in the solid inner contents of a cold pack into a Styrofoam cup. The Styrofoam cup is used as a simple calorimeter.
Place a thermometer and a s rring rod into the calorimeter (Styrofoam cup). CAUTION: Hold or secure the calorimeter AND the thermometer to prevent breakage.
Pour the 10 mL of water into the calorimeter containing the ammonium nitrate, (NH4NO3) taken from the cold pack.
Immediately record the temperature and the me.
Quickly begin s rring the contents in the calorimeter.
Con nue s rring and record the temperature at thirty second intervals in Table 1. You will need to s r the reac on the en re me you are recording data.
Collect data for at least five minutes and un l a er the temperature reaches its minimum and then begins to rise. This should take approximately 5 to 7 minutes.
Record the overall minimum temperature in the appropriate place on the data table.
Materials Safety Equipment: Safety goggles, gloves En re contents of a hand warmer S r rod 1/4 contents of a cold pack Spatula Calorimeters (2 Styrofoam cups)
Stopwatch Thermometer (digital) *Dis lled water 10mL Graduated cylinder *You must provide
62
Lab 5: Chemical Processes
Part 2: Hand Warmer
Wash and dry the thermometer. HINT: Remember to rinse it with dis lled water before drying.
Carefully place and hold the thermometer in another Styrofoam cup.
Cut open the inner package of a hand warmer and quickly transfer all of its contents into the calorimeter. Immediately record the ini al temperature of the contents and being ming the reac on. HINT: Data collec‐ on should start quickly a er the package is opened because the reac on will be ac vated as soon as it is
exposed to air.
Quickly insert the s rring rod into the cup and begin s rring the contents in the calorimeter.
Con nue s rring and record the temperature at thirty second intervals in Table 2. You will need to s r the reac on the en re me you are recording data.
Let the reac on con nue for at least five minutes and un l the temperature has reached its maximum and then fallen a few degrees. This should take approximately 5 to 7 minutes.
Record the overall maximum temperature in the appropriate place in the data table.
Data
Please submit your table data and answers for this experiment on the Word document provided to you.
Table 1: Cold pack data
Time (sec) Temp. ( 0 C) Time (sec) Temp. in (
- C)
Ini al 240
30 270
60 * 300
90 330
120 360
150 390
180 420
210 450
Minimum Temperature (0C) : __________
63
Lab 5: Chemical Processes
Table 2: Hand warmer data
Time (sec) Temp. ( 0 C) Time (sec) Temp. in (
- C)
Ini al 240
30 270
60 * 300
90 330
120 360
150 390
180 420
210 450
Maximum Temperature (°C) : __________
64
Lab 5: Chemical Processes
Graph your data from the tables on the Word document provided to you. You may create the graph on any program, but make sure it can be integrated into the Word document.
Ques ons 1. Calculate the overall temperature change (referred to as ΔT) for the cold and hot pack substance. HINT:
This is the difference in the maximum temperature and minimum temperature of each.
Cold pack ΔT:
Hand warmer ΔT:
Which pack works by an exothermic process? Use experimental data to support your answer.
Which pack works by an endothermic process? Use experimental data to support your answer.
Which pack had the greatest change in enthalpy? How do you know?
Lab 6: Light
67
Lab 6: Light
For centuries, scien sts have used op cal equipment such as lenses and mirrors to study the nature of light. Telescopes and microscopes take advantage of the proper es of light to create images from stars across the galaxy and to magnify objects hardly visible to the naked eye. In the late 19th century, James Maxwell proposed a series of equa ons that unify what we know about electricity and magne sm—it turns out that what we see as light is really electromagne c waves in wavelengths ranging from radio waves to gamma rays. Whenever subatomic par cles interact, they release or absorb energy in the form of electromagne c radia on, which travels through space in the form of electromagne c waves! Many mes, this electromagne c radia on can be detected by the human eye as visible light, but other kinds of light such as infrared radia on require special equipment to view.
Figure 1: This camera uses a series of op cal lenses so that the user can adjust for the intended focal point (f‐stop) and magnifica on of the
desired image.
Concepts to explore: · Electromagne c waves
- Speed of light
- Reflec on and refrac on
- Mirrors and lenses
68
Lab 6: Light
Electromagne c waves travel fast—so fast that it took scien sts many years to confirm that light does not travel at an infinite speed. Over the past half century there have been a number of experiments con‐ ducted to measure the precise speed of light. Modern experiments confirm the speed of light to be about 2.998×10
8 m/s, usually rounded
off as: c = 3.00×10
8 m/s
Just as sound travels at different speeds through different materials, the speed of light also changes depending on the medium it travels in. You can calculate how fast light travels in a material by using the equa‐ on
where n is equal to the index of refrac on for the material. The value of n for all sorts of materials has been found experimentally; some of these materials are listed in Table 1. This number tells us a lot about how light will behave within a material or as it crosses from one medium to another. Because electromagne c waves are so small and fluctuate so quickly, we can divide the light up into idealized lines called rays. You can imagine a ray as a straight beam of light, but in reality light is emi ed from a source in all direc ons. Reflec on occurs when a beam of light bounces off of a material. If the surface is smooth, the reflected beam leaves the surface at the same angle at which it approached. Thus we say that the angle of inci‐ dence equals the angle of reflec on, or θi=θr. You can see your reflec on in a mirror because rays of light from different points on your body reflect in this uniform manner. When a beam of light transmits from one medium to another, refrac on occurs. The direc on of light bends one direc on or another depending on the refrac ve index of each material. In general, when light travels from a material with smaller n to larger n, the ray will bend toward the normal (θ1 > θ2); if it goes from larger n to smaller n, it bends away from the normal. See Figure 2 for a diagram.
Table 1: Sample indices of refrac‐ on for several materials.
Material n
Vacuum 1 (exact)
Air 1.00
Water 1.33
Glass (Crown) 1.52
Diamond 2.15
Figure 2: Reflec on (le ) and Refrac on (right). No ce the direc on the ray of light bends as it moves from a material with larger index of refrac on to a smaller one, and vice versa.
V = c n
69
Lab 6: Light
Mirrors and lenses are devices that u lize the phenomena of reflec on and refrac on to create a num‐ ber of useful results for scien sts and engineers. A mirror is usually a polished metal surface that re‐ flects almost all of the light that lands on it. While it is easy to predict how a ray will bounce off of a plane mirror, such as the one in your bathroom, curved mirrors can produce some very interes ng re‐ sults. The following diagrams show how incident rays will reflect off of different spherical mirrors.
Figure 3: Rays incident on a convex (le ) and concave (right) mirror reflect outward or inward as shown above. Images form where the rays converge (real image) or where they appear to emanate from (virtual image).
- F
Figure 4: Rays incident on a convex (le ) and concave (right) lens reflect outward or inward as shown above. Convex lenses (le ) focus parallel incident rays through a single point, called the focus point. For this reason, they are some mes referred to as convergent lenses. Concave lenses (right) cause parallel incident rays to bend away from each other. In fact, they diverge away from each other as if they all began at the same focal
point (rather than converging at the same focal point, as with concave lenses )
- ●
70
Lab 6: Light
Parallel rays incident on a concave mirror all reflect toward the mirror’s focal point, which lies in front of the mirror. For a convex mirror, rays reflect outward in such a way that, if traced backward, they converge at a focal point behind the mirror (Figure 3). In each case, the focal point is halfway between the mirror surface and the center—the center of the imaginary sphere that the mirror surface shares: In the case of lenses, parallel rays refract through the lens material. For converging lenses, the rays converge at a focal point behind the lens. For diverging lenses, rays are refracted outward so that when traced backward they will intersect at a focal point in front of the lens. If the object is very far away from a concave mirror (we can say “at infinity”), rays hi ng the mirror surface will be pre y much parallel, and an image will form at the focal point in front of the mirror. In the case of a converging lens, rays refract through the lens and converge at the focal distance on the other side. A real image occurs when a mirror or lens focuses rays of light from all points on the object at a specific distance. If you know where all the light rays intersect, you could put a screen at that point and view the real image that forms there. The projec on screen at a movie theater, for instance, cre‐ ates a real image at the precise distance of the movie screen. Without a screen, you can view a real image by placing your eyes at just the right distance beyond where the image forms so that your eyes are focused at the image point—and an image will appear in the air in front of you! A virtual image occurs when rays coming off of a mirror or through a lens appear to originate from a specific spot, when really no actual object exists at that point. Virtual images are usually made with convex mirrors and diverging lenses. Your reflec on in a regular plane mirror is a virtual image—there is nothing really behind the mirror giving off light. With a concave mirror, the forma on of a virtual im‐ age depends on how close the object is to the mirror. An object closer than the mirror’s focal point is virtual and magnified, while an object placed outside the focal point creates a real image in front of the mirror that can only be seen clearly at the right distance (usually with a screen). When images form from spherical mirrors and lenses, o en mes the image appears to be larger or smaller than the original object. The magnifica on of a mirror or lens tells us how large or small the image is compared to the object. It turns out that the magnifica on (M) is also directly related to the image and object distances: Here the magnifica on is expressed as ra os of the image and object heights and distances. By conven‐ on, an inverted image has a nega ve image height, while an upright image is given a posi ve height.
Image distances are posi ve or nega ve depending on the conven ons listed in Figure 4. Consider a 3 cm tall object. If a lens forms an upright image that is 6 cm tall, the magnifica on of that lens is 2(or 2x, meaning “two mes”). On the contrary, an upside‐down image that is 1.5 cm tall yields a magnifica on of ‐0.5. As you can see, magnifica ons greater than 1 imply an image that appears larger than the origi‐ nal object, while magnifica ons less than one produce images that appear smaller than the original object.
f = c 2
M = h = ‐ si h0 so
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Lab 6: Light
Mirrors: concave: convex: All image and object distances are posi ve on the re‐ flec ng side of the mirror (object side) and nega ve if “behind” the surface.
Lenses: convex: f > 0 concave: f < 0 so > 0 if object is on side of mirror that rays enter si > 0 if image is on side opposite where rays enter (real image) si < 0 if image is on same side as where rays enter (virtual image)
Figure 5: The Lens Equa on The most useful equa on when dealing with mirrors and lenses is called the lens equa on. This equa on works well, as long as the mirror you are working with is not too curved (meaning, small in size compared to the radius of its curvature) and if the lens is thin. It relates the focal length f, the object distance, so , and the image distance, si.
The following sign conven ons allow you to use this equa on with both mirrors and lenses. In gen‐ eral, real images are said to have posi ve distances, and virtual images are said to have nega ve dis‐ tances.
Example Lens Equa on Calcula on: What image is produced when placing an object 9 cm. away from a convex lens that is 3 cm. long. Given: f = 3 cm. so = 9 cm. We need to solve for si to determine the image length. To do this, plug in the known variables and iso‐ late si on one side of the equa on. 1. 1 = 1 + 1 3 si 9 2. 3 ‐ 1 = 2 = 1 9 9 9 si 3. 9 = si 2 1 Answer: Si = 4.5 cm
1 = 1 + 1 f si so
f = ‐ C 2
f = C 2
72
Lab 6: Light
A ray diagram is helpful for showing how to find where images will form. Generally, three rays can be used to locate the image formed by a mirror or a lens. The following examples in Figures 6‐8 will give you a be er picture of how mirrors and lenses affect rays of light from objects.
Figure 6: A real image formed by a concave mir‐ ror. Note the inverted
orienta on and the mag‐ nifica on.
Example Ray Diagrams
Figure 7: A virtual image is formed in a
convex mirror.
73
Lab 6: Light
Experiment 1: Ray Diagrams To complete this lab, you will need to draw three, separate ray diagrams. The start of each diagram has been provided for you in the beginning of Procedure 1, Procedure 2, and Procedure 3, respec vely. It is important that you use a ruler when drawing to ensure that each diagram reflects the correct dimensions (listed at the top of every diagram.) When drawing your diagrams, remember that the distances measured along the axis should begin at the center of each lens (convex or concave). For example, a focal point that is marked at 5 cm should be posi‐ oned 5 cm away from the center of the lens. The diagrams indicate if the focal point or object is placed
to the right or le of the lens.
Note: The size of your computer screen and the amount of “zoom” perspec ve you have applied to the manual will affect the scales of the diagrams. It is important for you to rely on the numbers provided at the top of each diagram, rather than measuring the dimensions of the images provided in the manual, to create your diagram. When you have completed your diagram, take a picture of it (using camera phone, digital camera, webcam, etc.) or scan the image onto your computer. These diagrams should be included in the final doc‐ ument you submit with your post‐lab ques ons.
Figure 8: A real image formed by a convex lens. Again, note the inverted orienta on and the magnifica on.
Materials Ruler *White or graphing paper *Pencil *You must provide
74
Lab 6: Light
Procedure 1: Concave Mirror Please submit your ray diagrams and answers for this experiment on the Word document provided to you.
To begin, Ray 1 should be drawn horizontal from the top of the “object” and reflect through the focal point f. To help you start the diagram, Ray 1 has been drawn in for you.
Since rays trace the same path no ma er what direc on they are going, we can draw Ray 2 as the “reverse” of Ray 1: this ray should be drawn through the focal point first, then reflect off the mirror horizontally.*
Finally, Ray 3 should be drawn through the center point C of the mirror, and reflect direc on back through its origin. Why can we draw this ray like this (think about the radius of a circle)?
If done correctly, these lines should all intersect at one point! Draw your new arrow from the axis to the point of intersec on—what do you no ce about the orienta on of the real image?
Measure and record the resul ng image distance and image height from your diagram.
f = ___________ si = ___________ hi = ___________ * As another op on, a ray may be drawn that reflects off the mirror’s center. This ray will reflect at the same angle at which it is incident, as the mirror center is perpendicular to the horizontal.
so= 12.5 cm, C= 6.5 cm, ho= 4 cm
Ray 1
Object f
75
Lab 6: Light
Procedure 2: Convex Lens A Please submit your ray diagrams and answers for this experiment on the Word document provided to you.
To begin, Ray 1 should be drawn horizontally from the top of the object, and refract through the focal
point f. 2. Ray 2 goes directly through the center of the lens and does not refract. 3. Ray 3 goes through the focal length on the object side, then refracts horizontally through the lens. 4. Your three rays should intersect very at or very nearly at a single point. Draw in the resul ng image as
another arrow. 5. Measure and record the resul ng image distance and image height from your diagram.
si = ___________ hi = ___________
so= 8.8 cm, f = 3.2 cm, ho= 3.4cm
Object f f
76
Lab 6: Light
Procedure 3: Convex Lens B Please submit your ray diagrams and answers for this experiment on the Word document provided to you.
For this diagram, the first part of Ray 1 is drawn for you. Determine what kind of image will form based
on the placement of the object inside the focal length? Finish this ray by bending the it inward and down so that it passes through the right‐most focal point.
Ray 2 is a li le more complicated because the object is placed closer to the lens than it is to the focal point. Thus, the ray must be drawn as if it came from the focal point, travel towards the top por on of the lens, and converge slightly once through the lens.
Ray 3 begins at the top of the apex, and travels directly through the center of the lens. Is does not expe‐ rience any deflec on.
So far, these rays do not intersect. Therefore, to determine where the image is formed you must ex‐ trapolate the rays backwards un l they create an intersec on point.
Indicate where the new image will form on your ray diagram. What do you no ce about the size/ loca on of the image? Is this image real or virtual, and how do you know?
Object f
Ray 1
so= 3.7 cm, f = 6.0 cm, ho= 1.7cm
f
77
Lab 6: Light
Ques ons 1. Is the resul ng image for the concave mirror real or virtual, and how do you know? Use your meas‐
urements to calculate the magnifica on. M=__________________
For the concave mirror, use the lens equa on, magnifica on equa on, and the provided distances (not any measured image distances) to calculate si and hi. How do your measured values compare?
Is your image for Convex Lens A real or virtual, and how do you know? Use your measurements to
calculate the magnifica on. M=__________________
For Convex Lens A, use the lens equa on, magnifica on equa on, and the provided distances to calculate si and hi. How do your measured values compare?
Measure and record the image height and image distances for Convex Lens B.
Si =__________ hi =______________ 6. Is the image formed through Convex Lens B real or virtual, and how do you know? Use the lens
equa on to find si and hi , and compare this to the actual measurements.
78
Lab 6: Light
Experiment 2: Exploring Mirrors Concave and convex mirrors can create a variety of different images. A convex mirror reflects incoming rays outward from its center—these rays are perceived by your eye as origina ng behind the mirror as a virtual image. For a concave mirror, the forma on of either a virtual image or a real image depends on how close the object is to its focal point. In this lab you will examine how both types of mirror create real and virtual images.
Procedure / Observa ons 1. Look into the side of the mirror that bulges out toward you. Write down how the image appears
(orienta on and magnifica on) and how many objects you can see in the background. 2. Hold the mirror close to your face, and then gradually move it away. Note what happens to your image
as you get farther from the mirror. 3. Now turn the mirror over and look into the side that bends inward. Note down how the image appears
(orienta on and magnifica on) and how many objects you can see in the background. 4. Place this mirror as close as you can to your eyes and note what you see differently. Write down how
the orienta on and magnifica on change as you move the mirror farther away.
Ques ons Please submit your answers for this experiment on the Word document provided to you.
What kind of mirror did you use in Procedure/Observa ons 1—is it convex or concave?
Is your image in this type of mirror a virtual image or a real image? How do you know?
Did the convex mirror give you a good view of a lot of objects to either side of you? Where have you
seen mirrors like this used, and what do you think makes them useful?
Materials Concave/convex plas c mirror
79
Lab 6: Light
Is the other side of the mirror convex or concave? Comment on the magnifica on of this side of the mirror when it is held very close to your eyes. How does the magnifica on change as you move it away from your eyes?
Is this a virtual image or a real image? Draw a ray diagram for a concave mirror with the object placed inside the focal length (so < f ) to verify your answer.
Experiment 3: Exploring Lenses
Procedure 1 1. Hold the convex lens at about 30 cm in front of your eyes, and hold it up to different objects (such as
a ruler or your lab manual page). 2. Gradually move the lens farther from the object, and note what happens to your view of the object
through the lens. Record how the image appears and changes in the space below. 3. Repeat the above steps with the concave lens, and record your observa ons. 4. Use your observa ons to answer Ques ons 1‐2. Observa ons Please submit your observa ons and answers for this experiment on the Word document provided to you. Convex Lens: Concave Lens:
Materials 1 Convex lens 1 Concave lens Plain white paper* Wax paper Ruler * You must provide
80
Lab 6: Light
Procedure 2 1. Find an area in your room or home with a bright window. Try to dim the inside lights in the area so
that the window provides most of the light—it helps if you can use a curtain to limit the amount of light coming in.
View the window through the lens while holding it at arm’s length. Move the lens back and forth slowly un l you can see a clear image (if you can’t create an image easily, move yourself farther from the window). Once you can see a clear image answer Ques on 3.
Try to form an image of the window on your “screen” by changing the distance between the lens and the paper—this should occur when the lens is between 10 cm and 20 cm from the paper. Once you can make a sharp image, move on to Ques ons 4 and 5.
Ques ons 1. Describe the general orienta on and magnifica on of the images formed through the convex lens
before the image became blurry (this occurs when the image distance is larger than the distance from the lens to your eye).
What kind of image forms through the convex lens in the above situa on, and how do you know?
How does the image of the window appear through the lens at this distance? What kind of image is this, and how do you know?
At what distance must you posi on the screen in order to view a clear image on the paper?
Explain why the screen allows you to view this kind of image, but would not work in viewing the images from Procedure 1.
Lab 7: Radioac vity
83
Lab 7: Radioac vity
Concepts to explore: · Strong force
- Radioac vity
- Isotopes
- Nuclear decay
- Half‐life
All ma er consists of atoms. Most of ma er is actually empty space defined by electrons spinning around a small nucleus of protons and neutrons. Therefore, there is abundant space within an atom.
Protons and neutrons are a racted to each other by strong and weak forces. The strong force is one of the four basic forces in nature, and measures more than 100 mes stronger than the electric force. However, it is only ac ve in short‐ranges such as in the nucleus of an atom. The larger the nucleus of an atom the less affect the strong force has on the nucleus, as the electric force causes the protons and neutrons to repel each other. For this reason, the resul ng net force decreases as the size of the nucle‐ us increases.
The nucleus can decay and give off ma er and energy when the strong force is not large enough to hold the nucleus together. This process is called radioac vity. Nuclear decay occurs in all nuclei with more than 83 protons; these atoms are both unstable and radioac ve.
The number of protons in an atom is constant and represented by the atomic number (See Figure 2). In contrast, the number of neutrons present can vary. Atoms with the same number of protons and elec‐ trons, but different numbers of neutrons are called isotopes. Isotopes have the same chemical proper‐
Figure 1: If a nucleus was the size of
a grain of sugar, the electron cloud
would span 10m from the grain in
all direc ons!
84
Lab 7: Radioac vity
es, but the stability of the nuclei may differ. Nuclei that have too many or too few neutrons rela ve to the number of protons are considered unstable. The mass of an electron can be considered negligible com‐ pared with the mass of protons and neutrons; therefore, the mass of an atom can be considered equivalent to the combined mass of protons and neutrons in the atom. The combined mass gives rise to the mass num‐ ber.
Unstable nuclei are constantly changing as a result of the energy imbal‐ ance within the nucleus. As unstable nuclei decay, they emit par cles and electromagne c energy called radia on. Radia on is energy trans‐ mi ed through space in the form of electromagne c waves or energe c par cles. As radioac ve isotopes decay, they emit radia on only once. However, it may take several steps for an unstable atom to become sta‐ ble, and radia on will be given off at each step. For this reason, radioac‐ ve sources become weaker with me. As more and more unstable at‐
oms of a material become stable through successive radioac ve decay, less radia on is produced by the material and eventually the material will cease being radioac ve and unstable.
Radia on is a natural process and is categorized into three types, based on the decay product that is released: alpha, beta, and gamma. When alpha radia on occurs, an alpha par cle made of two protons and two neutrons is emi ed from the decaying nucleus. The alpha par cle has the charge of +2 and an atomic mass of 4. Therefore, when an atom loses an alpha par cle it undergoes a transmuta on, and becomes another element. They are the largest radia on par cle and also have the biggest electric charge, which makes them lose energy quickly when they collide with other ma er. As a result, the alpha par cles are the lowest penetra ng form of radia on, stoppable by a single sheet of paper. A second type of radia on is caused when an unstable nucleus loses an electron from the neutron. This is called beta radia on, and the electron that is lost is referred to as the beta par cle. This par cle is fast‐ er and more penetra ng than an alpha par cle, but can be stopped by a piece of aluminum foil. As with alpha radia on, the atom undergoes a transmuta on when beta decay occurs, becoming an ele‐ ment with one more proton and an atomic number one greater than before. The most penetra ng form of radia on is gamma radia on. Gamma rays have no mass or charge and travel at the speed of light, and require thick, dense materials (such as lead or concrete) to stop their penetra on. Gamma
rays are emi ed from the nucleus when alpha or beta decay occurs.
The behavior and effects of the radioac ve iso‐ tope (radioisotope) are influenced by the half‐ life of that isotope. The half‐life of a radioac ve isotope is the amount of me required for half the nuclei in the sample to decay into something else. It also provides informa on about the fre‐ quency of radioac ve emissions. Note that it does not represent a fixed number of atoms that disintegrate, but a frac on. A radioisotope with a long half‐life will only infrequently emit radia‐ on, while a short‐lived radioac ve isotope will
6C Figure 2: The nucleus symbol
includes the mass number
(above the C) as well as the
atomic number (below the C).
How many neutrons does car‐
bon‐14 have?
14
Radioisotope Half‐life
Polonium‐215 0.0018 seconds
Bismuth‐212 60.5 seconds
Sodium‐24 15 hours
Iodine‐131 8.07 days
Cobalt‐60 5.26 years
Radium‐226 1,600 years
Carbon‐14 5,730 years
Uranium‐238 4.5 billion years
Table 1: Half lives of Some Radioisotopes
85
Lab 7: Radioac vity
emit radia on repeatedly over a short period of me. Half‐life varies widely among the radioisotopes, from a frac on of a second to billions of years, as shown in Table 1.
Since the number of atoms present decreases by one half with the passing of each half‐life, the frac on of atoms remaining can be calculated as:
½ n = undecayed atoms
where n is the number of half‐lives that have passed. A er one half‐life, 1/2 of the atoms remain un‐ stable (and undecayed), and the other half became something else to achieve stability. A er two half‐ lives, 1/4 ((½)
) of the atoms in the sample are undecayed. A er three half‐lives, 1/8 ((½)
) atoms re‐
main undecayed, and so on. This expression demonstrates how sequen al decay events result in a re‐
duc on in the amount of unstable radioisotopes present. The decay pa ern follows the characteris c curve demonstrated in Figure 3 showing the decay rate of Carbon‐14.
Figure 3: Carbon‐14 has a half life of 5,730 years. A er 11,460 years (5,730 x 2) pass by, you might think that there are zero elements remaining. However, there are half as many as were present a er 5,730 years passed. The concept of half‐life is depicted in the graph above, showing how much of the element is present a er se‐
quen al half‐lives pass.
86
Lab 7: Radioac vity
Materials Ski les bag (approximately 60 candies) 5x8in. Resealable bag
Experiment 1: Es ma ng Half‐Life
While it would be nice to do an actual decay experiment, the me, money, and equipment required is unrealis c. Instead, you will use Ski les™ candies to demonstrate the concept of half‐life. The Ski les™ represent atoms.
Procedure
Count the number of candies in the Ski les bag. Record this number in Table 2.
Place all of the candies into the resealable bag.
Seal and shake the bag gently.
Pour out the candy onto a flat surface, and count the number of candies with the print‐side up (with the S on it). This represents the decayed atoms. Record this number in Table 2 next to the Trial number.
Return ONLY the pieces with the print side down into the resealable bag. Remove the print‐side up candies and set them aside (Note: You will repeat this experiment two more mes, so do not dis‐ card the Ski les™ you set aside!).
Repeat steps 3‐5 un l all of the atoms have decayed (Note: you may not need all rows in the table or you might need more rows).
Repeat the above procedure two mes, recording the results in Table 2. Average the number of decayed atoms for each trial, repor ng the calcula on in Table 2.
Calculate the percentage of decayed atoms based on the average number of decayed atoms for each trial. Put a check next to the trial with the calculated percentage of decayed atoms that most closely matches 1/2 (50%), 1/4 (25%), 1/8 (12.5%), and 1/16 (6.25%). You will use this data to plot a graph similar to Figure 3 showing the half‐life of Carbon‐14 for Ques on 3.
87
Lab 7: Radioac vity
Please submit your table data and answers for this experiment on the Word document provided to you.
Table 2: Half‐life experimental results
Ques ons
What is meant by the term half‐life?
At the end of two half‐lives, what percentage of atoms (Ski les™) have not decayed? Show your calcula on.
Total number of atoms
Trial Number of decayed atoms
Average
1st Round 2nd Round 3rd Round
1
2
3
4
5
6
7
8
9
10
Percentage of decayed atoms
(from original number)
88
Lab 7: Radioac vity
Using your data, graph the number of undecayed atoms vs. trials below to show when 1/2, 1/4, 1/8, and 1/16 of your Ski les remain (use the values next to the boxes you put checks next to in Step 8 of the procedure).
How would the graph change if 20 Ski les were used in this experiment?
If 1/8 of a radioac ve element remains a er 600 years, what is that element’s half‐life?
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Lab 3: Newton’s Laws Case Assignment
RUBRIC
QUALITY OF RESPONSE NO RESPONSE POOR / UNSATISFACTORY SATISFACTORY GOOD EXCELLENT Content (worth a maximum of 50% of the total points) Zero points: Student failed to submit the final paper. 20 points out of 50: The essay illustrates poor understanding of the relevant material by failing to address or incorrectly addressing the relevant content; failing to identify or inaccurately explaining/defining key concepts/ideas; ignoring or incorrectly explaining key points/claims and the reasoning behind them; and/or incorrectly or inappropriately using terminology; and elements of the response are lacking. 30 points out of 50: The essay illustrates a rudimentary understanding of the relevant material by mentioning but not full explaining the relevant content; identifying some of the key concepts/ideas though failing to fully or accurately explain many of them; using terminology, though sometimes inaccurately or inappropriately; and/or incorporating some key claims/points but failing to explain the reasoning behind them or doing so inaccurately. Elements of the required response may also be lacking. 40 points out of 50: The essay illustrates solid understanding of the relevant material by correctly addressing most of the relevant content; identifying and explaining most of the key concepts/ideas; using correct terminology; explaining the reasoning behind most of the key points/claims; and/or where necessary or useful, substantiating some points with accurate examples. The answer is complete. 50 points: The essay illustrates exemplary understanding of the relevant material by thoroughly and correctly addressing the relevant content; identifying and explaining all of the key concepts/ideas; using correct terminology explaining the reasoning behind key points/claims and substantiating, as necessary/useful, points with several accurate and illuminating examples. No aspects of the required answer are missing. Use of Sources (worth a maximum of 20% of the total points). Zero points: Student failed to include citations and/or references. Or the student failed to submit a final paper. 5 out 20 points: Sources are seldom cited to support statements and/or format of citations are not recognizable as APA 6th Edition format. There are major errors in the formation of the references and citations. And/or there is a major reliance on highly questionable. The Student fails to provide an adequate synthesis of research collected for the paper. 10 out 20 points: References to scholarly sources are occasionally given; many statements seem unsubstantiated. Frequent errors in APA 6th Edition format, leaving the reader confused about the source of the information. There are significant errors of the formation in the references and citations. And/or there is a significant use of highly questionable sources. 15 out 20 points: Credible Scholarly sources are used effectively support claims and are, for the most part, clear and fairly represented. APA 6th Edition is used with only a few minor errors. There are minor errors in reference and/or citations. And/or there is some use of questionable sources. 20 points: Credible scholarly sources are used to give compelling evidence to support claims and are clearly and fairly represented. APA 6th Edition format is used accurately and consistently. The student uses above the maximum required references in the development of the assignment. Grammar (worth maximum of 20% of total points) Zero points: Student failed to submit the final paper. 5 points out of 20: The paper does not communicate ideas/points clearly due to inappropriate use of terminology and vague language; thoughts and sentences are disjointed or incomprehensible; organization lacking; and/or numerous grammatical, spelling/punctuation errors 10 points out 20: The paper is often unclear and difficult to follow due to some inappropriate terminology and/or vague language; ideas may be fragmented, wandering and/or repetitive; poor organization; and/or some grammatical, spelling, punctuation errors 15 points out of 20: The paper is mostly clear as a result of appropriate use of terminology and minimal vagueness; no tangents and no repetition; fairly good organization; almost perfect grammar, spelling, punctuation, and word usage. 20 points: The paper is clear, concise, and a pleasure to read as a result of appropriate and precise use of terminology; total coherence of thoughts and presentation and logical organization; and the essay is error free. Structure of the Paper (worth 10% of total points) Zero points: Student failed to submit the final paper. 3 points out of 10: Student needs to develop better formatting skills. The paper omits significant structural elements required for and APA 6th edition paper. Formatting of the paper has major flaws. The paper does not conform to APA 6th edition requirements whatsoever. 5 points out of 10: Appearance of final paper demonstrates the student’s limited ability to format the paper. There are significant errors in formatting and/or the total omission of major components of an APA 6th edition paper. They can include the omission of the cover page, abstract, and page numbers. Additionally the page has major formatting issues with spacing or paragraph formation. Font size might not conform to size requirements. The student also significantly writes too large or too short of and paper 7 points out of 10: Research paper presents an above-average use of formatting skills. The paper has slight errors within the paper. This can include small errors or omissions with the cover page, abstract, page number, and headers. There could be also slight formatting issues with the document spacing or the font Additionally the paper might slightly exceed or undershoot the specific number of required written pages for the assignment. 10 points: Student provides a high-caliber, formatted paper. This includes an APA 6th edition cover page, abstract, page number, headers and is double spaced in 12’ Times Roman Font. Additionally, the paper conforms to the specific number of required written pages and neither goes over or under the specified length of the paper.
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