You know what’s fun? When your science lessons require you to make big messes. Or that’s what my kids think. I, as the Mom who is going to clean up that mess, don’t always agree with them. However, I could make this not as painful as it looked on paper to clean up. So, I present to you a fun (and messy) STEM physics potential energy experiment.
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Supplies for the potential energy experiment
This experiment came from our physics textbook a few years ago: Real Science 4 Kids: Physics, so you’ll need it for the lab sheets you’ll see in the pictures
Otherwise, if you don’t want to use the cool lab sheets: a long board or sheet (we had a random plank of wood from some project), toy car (ours was a Brio tank engine which I can’t find the same one, but it was perfect because it let us easily put the 10 pennies in the “chair”), ruler, kitchen scale (if you don’t have a kitchen scale there are so many lessons you can do with one), 10 pennies, cardboard (this seriously cuts down on the mess, and if you just ordered all this stuff from Amazon, then you have a nice empty cardboard box now)
Set up to ensure lack of mess and consistent results
Huh, in the book they suggest the cardboard. I’d totally forgotten that.
Okay, take your cardboard and using the amazing blue tape, apply it to your wall. This makes sure it doesn’t move on you. Next the book suggests pinning the banana to the wall with a straight pin, skip that. It doesn’t’ work.
Just put the board up against the wall, and then put your banana slice balanced on the board.
Then make a mark with your pen about 2 feet up on the board, this is to ensure you always release your car at the same point.
Going through with your potential energy experiment
First, weigh your car. Ours weighed 38 grams. Super heavy there, I know.
Then, using your ruler, measure lift your board up two inches at your mark, and let the car go. Record your results.
- Decide at the beginning will you measure from the bottom of your board or the top to keep consistency.
- Do a few test runs without the banana in place to find out if your car tends left or right. Ours tended right, so we had to correct for that.
Keep repeating the experiment, slowly moving the board up two inches each time you repeat it, and record when the banana is finally smashed by the car.
For us, that happened at 8 inches.
Now add 10 pennies to your car, you could tape them all in one place, or spread them out over the car. We placed ours in the chair, which held them nicely secure. I wonder what difference it might make if you experimented with different ways of placing the pennies (I didn’t think about this when we did it, missed opportunity).
Weigh your car again, and repeat the experiment with the redesigned car.
What do we learn about potential energy?
This is a great potential energy lesson because you can take it from a toy car smashing bananas to a slide on the playground. Which slide will they go faster on, the short slide that doesn’t have much or an angle, or the steeper slide? They almost always know it’s the steeper slide, but now they’re about to learn why.
Potential energy is measured by (super simplified here) gravitational potential energy, weight X height. So the higher you are, the more potential energy you have.
By the same factor, the more you weigh, the more potential energy you have. This is why my kids who picked different cars for their experiments got different results at different heights. That is also the reason for repeating the experiment with 10 pennies taped to your car.
Of course, once you get into high school and college, you’ll start learning about drag coefficients, and how to better streamline your car with the weight, but that’s not what we were going for here.
Today we were just trying a simple potential energy experiment.
More science fun to be had
- Atom unit study
- EEME review
- First Law of Motion Experiment
- Ionic Bonds experiment
- Bird Beak experiment
What’s your favorite messy science experiment?
This wasn’t all that messy, if I’m honest.