Bobsleds

Bobsleds use the low-friction surface of ice to coast downhill at ridiculous speeds. You start at the top of a high hill (with loads of potential energy) then slide down a icy hill til you transform all that potential energy into kinetic energy.  It’s one of the most efficient ways of energy transformation on planet Earth. Ready to give it a try?

This is one of those quick-yet-highly-satisfying activities which utilizes ordinary materials and turns it into something highly unusual… for example, taking aluminum foil and marbles and making it into a racecar.

While you can make a tube out of gift wrap tubes, it’s much more fun to use clear plastic tubes (such as the ones that protect the long overhead fluorescent lights). Find the longest ones you can at your local hardware store. In a pinch, you can slit the gift wrap tubes in half lengthwise and tape either the lengths together for a longer run or side-by-side for multiple tracks for races. (Poke a skewer through the rolls horizontally to make a quick-release gate.)

Here’s what you need:

• aluminum foil
• marbles (at least four the same size)
• long tube (gift wrapping tube or the clear protective tube that covers fluorescent lighting is great)

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If you’re finding that the marbles fall out before the bobsled reaches the bottom of the slide, you need to either crimp the foil more closely around the marbles or decrease your hill height.

Check to be sure the marbles are free to turn in their “slots” before launching into the tube – if you’ve crimped them in too tightly, they won’t move at all. If you oil the bearings with a little olive oil or machine oil, your tube will also get covered with oil and later become sticky and grimy… but they sure go faster those first few times!

 
Download Student Worksheet & Exercises

Exercises Answer the questions below:

1. Potential energy is energy that is related to:
   1. Equilibrium
   2. Kinetic energy
   3. Its system
   4. Its elevation
2. If an object’s energy is mostly being used to keep that object in motion, we can say it has what type of energy?
   1. Kinetic energy
   2. Potential energy
   3. Heat energy
   4. Radiation energy
3. True or False: Energy is able to remain in one form that is usable over and over again.
   1. True
   2. False

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