Lab 12—CPO Energy Lab

This is a very straight forward lab that is designed to get students to understand energy conservation. As the name of the lab would suggest, it does utilize the CPO equipment and a single photogate at the bottom.

To do the lab, set a CPO car and ramp system at an angle and put two photogates at the bottom. Drop the car from four different angles and measure the velocity at the bottom. Measure the time three times for each angle and then find the average time. Finish off by turning times into velocity by dividing the distance/time. When using one photogate, make students use the distance the photogate is blocked as the distance (for CPO equipment, that distance is .05m) Before dropping the cart, make sure you measure the height from which the car is dropped. After all your trials, have each lab group record the mass of their lab cart.

Sample answers:

1.The car with the highest height move the fastest since it had the most energy.

2. Graphs will vary

3. The line shouldn’t be straight since comparing v to h is a quadratic relationship

4-5. The numbers should be very close. Make sure students are careful to use m and kg when plugging into the energy equations

Name: ______

Period: _____

Physical Science—CPO Cart Energy Transformation

Questions:

Does increasing the height of a lab cart increase the energy at the bottom?

Research and necessary equations:

GPE= mass * gravity (9.8 m/s/s) *height (m)

KE= ½ mass * velocity (m/s) *velocity (m/s)

The CPO lab cart will block the timer for .05 m.

Hypothesis (create a hypothesis):

Will there be more or less energy at the bottom of the path?

Procedure:

  1. Set up a CPO track and lab cart system.
  2. Place a single photogate at the bottom of the track. Make sure the photogate is high up enough that the cart can stop it
  3. Release the carts from the top of the track. DO NOT STOP THE CART WITH YOUR HAND! Let it hit the rubber stopper on the bottom.
  4. Measure the time three times and find an average.
  5. Finally, take .05 m and divide it by the average time. This is the velocity of the car.
  6. Measure the height off the ground you released the carts.
  7. Repeat the experiment for five different heights

Data table:

Height Released / t1 / t1 / t1 / taverage / velocity

MASS OF CAR: ______

Analysis:

  1. Which car moved the fastest? Why do you think that was? Your answer should have the word energy in it.
  1. Graph Starting Height (dependent) and velocity (independent) for each trial.

  1. Do you have a straight line? Should you? Why or why not?
  1. For your second trial. Calculate the GPE at the beginning of the trial and calculate the KE at the end of the trial. How do these numbers relate.
  1. Do the same thing (calculate GPE and KE) for you third trial. How do the numbers relate this time?

Conclusions:

Write 2-4 sentences that discusses your answers to the questions.

Lab 13—Tennis Ball Lab

This is a difficult lab to accomplish but easy to set up. The idea is quite simple: bounce a tennis ball and see how much energy is lost in each bounce. The calculations are straight forward. As a note, if students are having trouble understanding the law of conservation of energy, this might not be the best lab as it shows the loss of energy in a system.

To do the lab, drop it from a certain height. Have each lab partner keep track of how high each progressive bounce goes. I suggest having each lab partner use a hand to mark where the ball goes up to. Each group might have to try several trials just to get one data trial. After each trial, have students calculate the PE for each height. You will need to measure the mass of a ball in order to do this!

Sample answers:

1.Answers will vary

2. Graphs will vary

3. The line shouldn’t be straight since comparing v to h is a quadratic relationship

4. Set PE = KE and use the equation KE = ½ mv2 to solve for v

5. Solve for each loss in energy by subtracting columns 2 and 8

6. The energy will transfer from one ball into the other

Name: ______

Period: _____

Physical Science—Loss of Energy lab

Questions:

Does increasing the height of a lab cart affect how much energy it loses?

Research and necessary equations:

GPE= mass * gravity (9.8 m/s/s) *height (m)

KE= ½ mass * velocity (m/s) *velocity (m/s)

The CPO lab cart will block the timer for .05 m.

Hypothesis (create a hypothesis):

Procedure:

  1. Hold a tennis ball a set distance off the ground. Measure that distance.
  2. Drop the tennis ball straight down and let it bounce.
  3. Have one partner determine the maximum height after one bounce.
  4. DO NOT STOP THE TENNIS BALL! Allow it to bounce twice more.
  5. Have each lab partner keep track of how high the ball went.
  6. Measure the height off the ground for each trial and record that in the white sections of your data table
  7. Repeat the experiment for three different starting heights.
  8. Calculate the PE of each height by calculating PE = m *g * h

Data table:

Height Released / PE 0 / Bounce 1 / PE 1 / Bounce 2 / PE 2 / Bounce 3 / PE 3

Analysis:

  1. For you last data trial, how much energy was lost between the start and bounce 1? (Take column 2 and subtract column 4) How much energy was lost between bounce 1 and bounce 2? ( Take column 4 and subtract column 6)
  1. Create a line graph of potential energy (the grey boxes) on the dependent and trial number (0,1,2,3) on the independent for each trial. YOU SHOULD HAVE 3 LINES!
  1. Do you have a straight line? Should you? Why or why not?
  1. Since PE turns into KE on the ground. Calculate a velocity of one of your trials from the height released height
  1. During which trial was the most energy lost? Prove it by showing calculations for the total energy lost of all 3 of your trials.

Conclusion

  1. If you drop two tennis balls from waist high, they both hit the ground, and only one bounces back up, why will it bounces twice as high as it was released

Lab 14—Food Drop Lab

This is a fun lab that is messy and gets students into energy! This is an outdoor lab that you can use to get kids into energy conservation.

To do the lab, you need a long tape measure, a supply of eggs, a large tarp and some stopwatches. Find a large outdoor staircase (such as bleachers) and lay a tarp underneath it. Measure the distance from various points on this staircase to the bottom and have students drop eggs from each height. Make sure you time the egg’s drop. This lab does make a mess but students enjoy senseless destruction!

Sample answers:

1.Graphs will vary

2. Answers will vary. The units will be J/s.

3. The numbers should be the same for each trial

4. The PE should go up for each trial

5.The energy would belarger but the time would be the same to the bottom!

Name: ______

Period: ____

Physical Science—Food Drop Lab

Questions:

  • Does a heavy object have more or less kinetic energy as a light object dropped from the same height?
  • How does increasing the height affect dropping velocity?

Research and necessary equations:

GPE= mass * gravity (9.8 m/s/s) *height (m)

KE= ½ mass * velocity (m/s) *velocity (m/s)

ME = KE + GPE

To turn time into velocity at the bottom, use the following equation

vf = time (9.8 m/s/s)

Hypothesis (create a hypothesis):

How does increasing the height affect dropping velocity?

Part I (Egg Drop):

  1. As a class pick six different heights. (wait until we are out there!)
  2. Mass an egg. Record that mass in the data table
  3. The class will have several rolls (circle your roll):
  4. Massersb. Droppersc. Measurersd. Recorders e. Timers
  5. Climb the stairs and aim the egg to drop onto a tarp.
  6. Count down: “3 … 2… 1… DROP”. Have the timers start their stopwatches and stop them when the egg hits the ground.

Data table:

Height Released (h)
Potential
( m* (9.8) * h)
Time to bottom (t)
Velocity (v)
(time * 9.8)
Kinetic Energy
(.5 *m *v2)

Mass of an egg: ______

Analysis:

  1. Graph potential energy (dependent) and time (independent) for the data. Then, with a different color, graph kinetic energy (dependent) versus time (independent).

  1. What is the slope of both of your lines? (You will need two numbers!)
  1. How does the KE and PE relate for any trial?
  1. How does the PE change for each of the trials?

Analysis

  1. How would the time to the bottom change if you used a more massive object?

Lab 15—Pendulum Lab

This is pretty easy lab that does a good job of exploring the relationship between PE and KE. Because this lab is easy but very important, it is a great lab to use while review for the EOC. It both has a graph as well as a KE/PE calculation.

To do the lab, you simply need stopwatches, string (I suggest fishing line as it is strong and not elastic), and mass. Hang a mass on the string and let it go for five full swings. Make sure students know a swing is a down and back, not just reaching the top point of the trip. After one trial, divide the time by five to get the overall period.

Sample answers:

1. Graphs will vary

2. The mass shouldn’t change anything. The length should change the period.

3. It is much more accurate

4.PE= m *g * h

5.Set the PE= ½ mv2…

6. Max PE are at the two edges. The Max KE is the very bottom of the path

Name: ______

Period:____

Physical Science—Pendulum Lab

Purpose:

To observe the laws governing simple harmonic motion

Safety/background:

Make sure the mass is securely attached to the pendulum so it does not swing off

Make sure the pendulum is attached to the lab station so it does not fling off

Hypothesis:

As the mass is increased, will the pendulum swing faster/slower/ the same?

As the distance of the string is increased, will the pendulum swing faster/slower/the same?

Procedure:

  1. Create a pendulum by attaching 10 cm of string to the top of a ring stand. Attach a 100 gram mass to the end of the pendulum
  2. Let the pendulum go (from a 90 degree angle) and measure the amount of time it takes to swing back and forth 5 times. Record this time
  3. Find overall period of oscillation by dividing by 5.
  4. Change the mass on the pendulum and repeat the process.
  5. Change the length of the pendulum and repeat the process.

Data:

Length of Pendulum / Mass on Pendulum / Period for 5 oscillations / Oscillating time

Analysis:

  1. Create a bar graph of oscillating period on the y axis and the trial type on the x axis (you will have four bars). You should think of a creative way to color and key your graph!

  1. How did changing the mass effect the swing? The length of the string?
  1. Why is measuring five swings of the pendulum better than measuring one swing?
  1. Calculate the maximum PE of your second trial.
  1. Given the PE in your previous trial, solve for the velocity at the bottom of the swing.

Conclusion

  1. On the picture below, circle points of the highest KE. Color in the points of highest PE.

Lab 16—Ramp Lab

This is a lab that is always surprisingly hard for students to understand but the principle is straight forward. The idea is to show that a tool does not change “the work”. This lab utilizes the CPO equipment and spring scales. Any tool of measuring force will work however.Although it takes a bit to set up, this lab does a great job of driving home the point that machines do not change the work done!

To do the lab, students will be lifting a lab cart 30 cm off the ground. This is important to understand, since students will not change the height the car increases each trial. However, for trials other than the first one, they will include a ramp and increase the distance over which you have to pull up the cart (increasing the distance traveled, but not the height!). Have students pull the cart slowly up the ramp (or off the ground for trial one) and determine the force and the distance over which they pull the cart. Record that information in the data table. If all goes as planned, the work done (force x distance) should be the same for each trial.

Sample answers:

1.They require the same work since a ramp doesn’t change the work!

2. Graphs will vary

3. Slope will vary. Units are J/degree

4.It increases the distance so decreases the force you need to apply

5.screw—decreases the distance so increase the force applied

lever—increases the distance so decreases the force you have to apply

Name: ______

Period: _____

Physical Science—Ramp Lab

Background

Work is measured in Joules, Force in Newtons, and distance in meters.

Hypothesis:

Does moving a car up a ramp increase or decrease the work done on the car?

Procedure:

The car should start from rest on the ground and end at the height of the ramp.

Part 1: Without the Ramp

  • Measure the distance from the floor to the top of the ramp and record in the data table.
  • Using the spring scale, lift the car straight up through the air (not along the ramp) and record the force measured by the spring scale.
  • Calculate the work done to lift the car to this position and record in the data table. Remember, work is force times distance, when force and distance are in the same direction!

Part 2: With the Ramp

  • Measure the distance along the ramp and record in the data table.
  • Using the spring scale, pull the car up along the ramp and record the force measured by the spring scale.
  • Calculate the work done to lift the car to this position and record in the data table. Remember, work is force times distance, when force and distance are in the same direction!
  • After you do this, try putting the ramp at different angle and increase the amount of track you use. Make sure however that you go up to the same height each time

Data:

Angle: / Distance Traveled (m) / Force (N) / Work (J)
0˚ (no ramp) / . 3 m
(with Ramp)
(with Ramp)
(with Ramp)

Analysis:

  1. Which would require less work to lift an object to the same height – a longer ramp or a shorter ramp? Why?
  1. Create a graph of angle (your x axis) and work on the (y axis).

  1. Find the slope of your line
  1. How does a ramp make doing the work easier?
  1. What properties do the following simple machines have that make workeasier? Keep in mind, you can only change Force or distance!

a. a screw

b. a lever

Lab 17—Work and Power Intro Lab

This is a straightforward lab that introduces the concepts of work and power. If the weather is nice, this lab is best accomplished outside on bleachers. However, it can be done just as easily in the staircase of your school. This is one of the longer labs so make sure you plan accordingly.

For the lab you will need stopwatches and meter sticks. Without going into the details of all the steps and procedures, the lab can be summed up easily. PART I: Have students walk/run 2 known distance and time them. PART II: Have students walk for a known time and then measure the distance. Try to have students “walk” at the same speed and “run” at the same speed of the data will get messed up. As a safety concern, make sure the stairs are not slippery and groups are reasonably spread out. Also, prevent asthmatic kids from being the walk/runners for obvious reasons!

Sample answers:

PART I:

1. 1.Take their mass and convert to kg (lbs / 2.2). Multiply by 9.8 to get their force due to gravity

2. Multiply the distance they walk to get the two works done (answer to #1 x distance for each trial)

3.Take the answers to #2 and divide by the times it took to do the work!

2. The work is the same but running takes more power

3.It takes more work to go up higher but the power stays the same

PART II:

  1. Graphs will vary
  2. Slopes will vary except the unit will be J/s
  3. Find the power by doing Work / time
  4. The numbers should be the same! The units are the same

Name: ______

Period: _____

Physical Science—Work Lab

Questions:

How much work does it take to go up and down stairs?

How much power does it take to go up and down stairs?

Research and necessary equations (answer the questions):

  1. What is work defined as?
  1. What is power defined as?
  1. What are the units for work? What are the units for power?

Hypothesis (create a hypothesis):

PART I:

Procedure:

  1. In your group, assign each person one of these rolls: (circle your roll)
  2. Climberb. Timerc. Measurer/spotterd. Recorder
  3. Estimate or measure the mass of you climber in kg. You may need to convert his/her pounds to kilograms by dividing by 2.2. (2.2 lbs = 1 kg)
  4. The measurer should record the height of each stair and then multiply by the number of stairs. In other words, how high up did the walker go? Record this in Table 1.
  5. Have the climber walk to the top of the stairs and have the timer record how long it takes to do this. Record the time in the table.
  6. Repeat step 4 but run up the stairs.
  7. Repeat the experiment, but walk up twice as many stairs.

Data table: