Home School Life Journal From Preschool to High School

Home School Life Journal ........... Ceramics by Katie Bergenholtz
"Let us strive to make each moment beautiful."
Saint Francis DeSales

The Energy Can

For science this week, James went back to his physical science study of roller coasters by making this Energy Can and Quentin went back to where we left off in human biology, with the lymphatic system.

James' Energy Can demonstrates stored and kinetic energy. If you are interested in doing James' project, you will need:

an empty coffee can (1-lb. and 5'' diameter w/plastic lid)
Fishing sinker (1 oz.)
1-2 Long Rubber-bands (6'')
2 paper-clips
With a hammer and nail, punch one hole through the bottom of the can and one in the center of the plastic lid. 

Thread the paper-clip onto one end of the rubber-band. Then thread the other end of the rubber-band through the hole in the bottom of your can. The clip should be on the outside of the can.
Slide the sinker onto the middle of the rubber-band.
Thread the free end of the rubber-band through the hole in the lid.
Attach the paper-clip to the rubber-band on the plastic lid so the band won't slip into the can.
Place the plastic lid tightly onto the end of the can.
Now you can explore potential and kinetic energy with this toy. Keep in mind the mathematical formula:

Potential Energy + Kinetic Energy = Total Energy

Can you predict where the potential energy is going to be the highest? Where is the kinetic energy going to be the highest?

Once you have made your predictions, push the Energy Can slowly across a smooth floor, and watch it travel until it stops by itself. Now, push it rapidly across the floor and watch it until it stops.
What did the Energy Can do when pushed slowly?
What did the Energy Can do when pushed rapidly?
How is the behavior of the Energy Can different from an ordinary can?

What conclusions can you make? 
Why do you think the Energy Can acts differently from an ordinary can? 
Where was potential energy the highest? Why?
Where was the kinetic energy the highest? Why?
Where is the potential energy the highest on a roller coaster?
Where is the kinetic energy the highest on a roller coaster?

As the Energy Can travels, some of its kinetic energy is changed to thermal (heat) energy in the form of friction. The thermal energy is waster kinetic energy. It does not help the Energy Can move so the can slows down. The potential energy was highest at the point where the Energy Can stopped moving away from you after the first push because that is where the most energy was stored inside it. Later trips lose more and more kinetic energy to friction, so it cannot build up as much potential energy. 
The same thing happens with a roller coaster. As the coaster train is towed by electrical energy to the top of the first hill, the train gathers potential energy. The top of the first hill is where the train has the most potential energy. As the train travels to the bottom of the first hill, this potential energy is converted to kinetic energy. The bottom of the first hill is where the kinetic energy is the highest. The total potential and kinetic energy can never be more that what the electrical energy gave the train. In addition, friction converts some of the kinetic energy into thermal energy instead of movement, wasting some of the kinetic energy. 

The Law of Conservation of Energy states that energy cannot be created or destroyed, only changed in form. How does this apply to the Energy Can or roller coasters? As we learned in Newton's First Law of Motion, the roller coaster cars will continue to move until another force, in this case friction (wheels on the track and the coaster's brakes), acts upon them.


  1. Wow. If I wasn't already blown away by your new kitchen, the backsplash would have done it for sure! Gorgeous, all of it.
    I'll have to show my kids the Energy Can. It looks like something they'd find really interesting.

    Random question for you, Phyllis: A couple of years ago you did a unit with one of your kids that involved a restaurant scenario (tostadas spring to mind for some reason) and math. Could you please share the company name? I'm blanking out.

    1. It was from Math on the Menu by Great Explorations in Math and Science.

  2. You always explain scientific concepts in a way that makes sense to me, despite not having really studied physics at school.
    Good luck with the remodelling!

    1. Thank you so much for your kind words.

  3. Happy birthday to both your boys! I can't believe you have one more graduating :) It all goes so quickly, doesn't it?

    1. I am actually graduating two this year. Yes, it does go fast.

  4. Happy birthday to the boys. What fun learning going on their as usual. Happy graduation too. They graduate on my birthday.
    Blessings, Dawn

  5. I was reading your post thinking, "I hope she tells us how to make that can, it sounds fun." And then you did. So happy dance!

    Happy birthday to Quentin and Sam (I had to go back and reread because I missed seeing Sam's the first time through, and was confused by all the boys plural statements)!

  6. Yep, we have two birthdays in May. I am glad that I included the instructions for the Energy Can then! I was thinking about saving it for a post once I completed a bunch of activities on one topic. I am glad now that I didn't wait.

  7. Happy birthday to Quentin and Sam! Wishing them a year of abundant blessings :)

    Your kitchen turned out just beautiful, Phyllis!!

    So it was a blast to the past. I remember doing that experiment sometime in my childhood. Can't recall exactly, but wow! You definitely jogged a memory cell in me this morning :)


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