Relating Graphs, Position and Speed (No Time Graphs)

Relating Graphs, Position and Speed (no time graphs) for Conservation of Energy http://phet.colorado.edu

Learning Goals: Students will be able to: 1. Describe Energy -Pie, -Bar, and -Position Charts from position or selected speeds. a. Explain how changing the Skater affects the situations above. b. Explain how changing the surface friction affects the situations above. 2. Predict position or estimate of speed from Energy -Pie, -Bar, and -Position Charts 3. Look at the position of an object and use the Energy -Pie, -Bar, and -Position charts to predict direction of travel or change in speed.

1. Josie made a frictionless hot wheel track that looks like the one shown. She placed a red rubber ball on the 1 3 left top of track at 1. a. Make a data table like the one below b. Fill in the Prediction column by sketching what you think the Pie chart will look like for the 4 ball at points 1-4. c. Use the Loop Track with the Ball Skater to 2 test your ideas and make any adjustments

Link: http://phet.colorado.edu/sims/energy-skate-park/energy-skate-park_en.jnlp Pie chart Prediction Simulation Explain differences

1 PE PE same

2 KE KE same

3 PE .PE same

4 KE equal Skater reached equilibrium

2. Pretend that Josie can magically change the ball to different things like the simulation can. a. What do you think would change about the Pie Charts? Nothing, because mass has no effect on Kinetic Energy. b. Explain why you think the charts would be similar or different. The charts would be the same because mass has no effect on Kinetic Energy. c. Check your reasoning using the simulation and make corrections if necessary. I was right! :)

3. Josie has a friend, Phillip that can magically change the friction on the track like the simulation can. a. What do you think would change about the Pie Charts? I think friction would not change the pie charts. b. Explain why you think the charts would similar or different. I think the charts would not change because the amount of energy would not be affected by friction.

5/11/2018 Loeblein http://phet.colorado.edu Relating Graphs, Position and Speed (no time graphs) for Conservation of Energy http://phet.colorado.edu

c. Check your reasoning using the simulation and make corrections if necessary. I was right! :)

4. Work with your partner to build a track and sketch it. a. Make a table like the one you did for question 1. b. Predict what you think the charts will look like. c. Use the simulation to check your ideas. d. Test your ideas from questions 2 and 3. Make changes to your answers if necessary.

1. 2. 3. 4.

Pie Chart Prediction Simulation Explain Differences 1 PE same NA 2 KE same NA 3 PE same NA 4 KE same NA

5. Explain how you can use what you understand about pie charts to predict bar charts. Pie charts and bar charts show the same thing just in different ways. If there is more pieces of the pie than there are more bars on the chart.

6. Sketch this track and label where the 5 spots could be.  Maximun speed: sad face  He is stopped NOWHERE!  He is going his average speed diamond  He is going slow flower  He is going fast lightening arrow

5/11/2018 Loeblein http://phet.colorado.edu Relating Graphs, Position and Speed (no time graphs) for Conservation of Energy http://phet.colorado.edu

7. Sketch this energy-position graph and label where you think the same 5 spots are.

a. Test your ideas using the Double Well Roller Coaster track. b. If one of your friends in the class asked you for help making sense of this type of graph, what would you say? I would tell my friend that when Kinetic Energy is at its high Potential Energy is at its low because of the relationship TME=KE+PE.

8. Talk about how you could use the Energy -Pie, -Bar, and -Position charts to predict direction of the ball is rolling. One could predict the direction the ball is rolling by looking at the amount of Kinetic Energy versus Potential Energy the ball has over a time span. For instance, if the chart goes from high potential energy to high kinetic energy the ball is rolling down a slope and vice versa.

a. Check your ideas using the simulation. b. Talk about how you could tell if the ball is going to be moving faster, the same, or slower. One could tell if the ball is moving faster, the same, or slower by looking at the Potential Energy versus the Kinetic energy. If the levels of PE and KE do not change the ball is moving at the same speed. If the PE is higher than the KE and then decreases the ball is speeding up because it is going down a slope. If the KE is higher than the PE and decreases then the ball is slowing down because it is going up a slope. c. Pretend you are writing a test for this unit. Type a question that includes at least one type of graph and a Skater on a different track. At which point does the Skater have the greatest Potential Energy?

Graph at Point A Graph at Point B Graph at Point C Graph at Point D KE PE TME KE PE TME KE PE TME KE PE TME

5/11/2018 Loeblein http://phet.colorado.edu