Fun Experiments to Show Kinetic and Potential Energy

Kinetic and potential energy are important ideas in physics, and there are fun ways to see them in action! Here are some easy experiments that work well for middle school students. They focus on how energy changes from one form to another.

1. Ball Drop Experiment

Goal: To see how potential energy (PE) changes to kinetic energy (KE) when a ball falls.

• What You Need: A ball (like a tennis or basketball), a measuring tape, and a stopwatch.
• How to Do It:
  1. Measure a height (like 2 meters) and drop the ball from there.
  2. Use the stopwatch to time how long it takes for the ball to hit the ground.
  3. Find the potential energy at the starting height using this formula: $PE = mgh$ Here, $m$ is the mass (weight in kilograms), $g$ is gravity (about $9.81 \, m/s^2$), and $h$ is the height (in meters).
  4. Calculate the kinetic energy just before the ball hits the ground using: $KE = \frac{1}{2} mv^2$ You can find $v$ (speed) by using $s = vt$ to get the time.
• Talk About It: Discuss how the potential energy turns into kinetic energy as the ball falls down.

2. Pendulum Swing

Goal: To see how kinetic energy and potential energy change in a swinging pendulum.

• What You Need: String, a weight (like a washer), and a protractor.
• How to Do It:
  1. Make a simple pendulum by tying the weight to one end of the string and securing the other end.
  2. Pull the pendulum back to a certain angle and measure the height.
  3. Let go of the pendulum and watch how the energy changes at the lowest and highest points of the swing.
• Calculations: At the highest point, potential energy is the most while kinetic energy is the least. At the lowest point, it’s the opposite. Use the same formulas from earlier to calculate PE and KE.

3. Rolling Objects Down a Ramp

Goal: To learn how potential energy changes into kinetic energy when objects roll down a ramp.

• What You Need: A ramp (you can make it from cardboard), different balls (like a marble or tennis ball), and a ruler.
• How to Do It:
  1. Set the ramp at an angle (like 30 degrees).
  2. Measure how high the ramp is from the ground.
  3. Let each ball roll down from the same height and time how long it takes to reach the bottom.
• Data Collection: Write down the weight of each ball, calculate potential energy at the start, and then calculate kinetic energy based on how fast it goes at the bottom.

4. Hovercraft Experiment

Goal: To show kinetic energy in a fun way.

• What You Need: A CD, a balloon, and a spray nozzle.

• How to Do It:

  1. Blow up the balloon and put it over the hole in the center of the CD. Then let go.
  2. Watch how the air pushes the CD across a smooth surface.

• Talk About It: This experiment shows how the potential energy stored in the balloon turns into kinetic energy when the air is released.

These experiments are not only fun but also help you see and understand kinetic and potential energy. They are great for engaging middle school students in physics!