### Materials

• Computer with internet and smart board connections
• Smart board
• Meterstick

### Prior Knowledge

1. Students know that energy is conserved and cannot be created or destroyed.
2. Knowledge of the main types of ways energy is stored is useful, but not necessary.

### Purpose

The purpose of the lab is to deduce the formula for gravitational potential energy based on empirical data collected using the Phet “Energy Skate Park” simulation.

### Experiment

1. Launch the simulation, change the skater to “star skater,” click “show grid” and “bar graph,” and select a volunteer to work the smart board.
2. Let students play for a minute before beginning with the guiding questions.
3. From these questions, students should come to the conclusion that the mass, gravitational field strength, and height affect the potential energy.
4. Fix two variables and measure how changing the third affects the size of the potential energy bar graph for a range of values.
5. Repeat for the other variables.

#### Guiding Questions

• “What do you notice is happening in the bar graph?”
• "What do these observations tell us about the properties of the skate track?"
• “What could we do to isolate the potential energy graph?”
• “What variables can we probe with this simulation?”
• “Based on the data, what can we conclude about the relationship with x to gravitational potential energy?”

### Analysis

1. Have students create plots of potential energy vs. each variable (time permitting).
2. After getting several data points for each variable, students should decide the type of relationship between it and potential energy.
3. From these observations, the students as a class should come to a consensus on what the formula for gravitational potential energy is.
4. After getting E­­grav=mgh, ask if there are any other factors the energy could depend on.