With the arrival of warmer weather, students love to spend more and more time on the playground. However, most kids rarely consider the playground what it can be - a source of scientific knowledge! Playgrounds consist of endless opportunities to teach elementary physics, one of my favorite scientific instruments being the slide. Ask your students if they’ve ever wondered why they can get moving faster on some slides than others? Why do some people get to the bottom before others? The answer lies in the energy used between the top and bottom of the slide.
There are two types of energy with which upper elementary students should be familiar. Put simply, potential energy is energy that is stored up, while kinetic energy is the energy of a moving object. A child at the top of the slide has lots of potential energy, but almost no kinetic energy. However, once they scoot over the edge, they have little potential energy and a larger amount of kinetic energy. Kinetic energy is affected by many things, including the child’s mass and the amount of friction between them and the slide. There are mathematical equations that allow physicists to find the amounts of potential and kinetic energy, but elementary students can have fun simply investigating the concept.
To make the ideas of kinetic and potential energy more real to your students, give them some wax paper, salt, water, butter, flour, checkers, cardboard, tape, a stopwatch, and a ruler. Then ask them to conduct the following investigation.
1. To make a basic slide, cut a piece of cardboard about two feet long and tape a strip of wax paper to it (tape only at the top). Prop it up at approximately a 45-degree angle. Repeat this process with 4 other pieces of cardboard.
2. Drizzle some water on Slope #1.
3. Spread a thin layer of butter on Slope #2.
4. Sprinkle some flour on Slope #3.
5. Crumple the wax paper into a ball and smooth it out (you may have to re-tape it to the top of the cardboard) for Slope #4.
6. Do nothing to Slope #5. This slope is your control.
7. Place a checker piece at the top of each slope and release it. Record the time it takes to reach the bottom of the slope or stop moving. Record the distance it traveled along the slope as well.
After the activity, ask students to identify the type of energy displayed by the checker both at the top of the slide and while it was moving. On which slide did it have the most kinetic energy, and the least? How does friction affect kinetic energy? Challenge students to create their own investigations: How does wind resistance (a fan) affect the checker? What happens if more mass is added to the checker? How does the angle of the slide affect the time it takes for the checker to reach the bottom? The possibilities are endless!
For more ideas on teaching kinetic and potential energy, try the following lesson plans:
Potential and Kinetic Energy Lesson Plans:
In this lesson students use household items, and toys,including Tinker Toys, to build contraptions that can make a ball move in order to hit a target. This is a fun way to bring out the inventor in every student.
This lesson introduces students to the idea of energy. They learn the definitions for energy, potential energy, and kinetic energy. They perform an experiment that helps solidify these concepts.
Students explore the effect of different factors on potential energy. They investigate how height and weight affects potential energy. By performing experiments, students evaluate this idea.