Tuesday, July 26, 2011

Race car ramp

All you need is a paper towel tube, some packaging tape, a raised surface, and a smallish object that rolls (but not too small...don't want anyone to choke).  We used a decent sized bouncy ball and a matchbox car.

Cut the paper towel tube in half and tape together with packaging tape.  Place to your desired height on a raised surface.  Race away!

Here's a video demonstration for you.

J plays California ramp in the middle (earthquake) - but that's the joy of this experiment - kids can take apart and fix the ramp to their heart's content.

Things to play with and consider:
*Height of ramp
*Where you start the object on the ramp (related to height too)
*Weight of object
*Type of object rolling
*Surface the object ends up on after the ramp
*The ramp might tip depending on slope of the ramp and momentum of the car - it's a very cheap yet entertaining science project, so no complaining.  If it bothers you too much, change where you start your object, change the angle of the ramp, or tape down the underside of the ramp.

Concepts(in case you have a really curious 2 year old and want to sound smart to your child and give him/her new vocabulary)

Transfer of Energy:

  • Potential Energy is mass x gravity x height (an object placed up high will potentially fall down), the higher it is or the heavier it is, the more potential energy it has.
  • Kinetic Energy is 1/2 x mass x velocity squared (kinetic is a fancy term for "motion" - once in motion, an object has velocity)

In an ideal world, the energy will transfer perfectly, meaning Potential Energy = Kinetic Energy, for our ramp set-up.  However, our world is less than ideal.  We have to deal with losses, mostly due to friction, which is the roughness of our surface.  Measuring losses would be another lesson for a little bit older age group (we did it in college physics) but it is doable with knowing all your variables listed above (you can measure velocity with photogates).***

*What happens when you raise the ramp or start the object higher on the ramp?
*What happens when you try a different object on the ramp?  Which object rolled better?  Why do you think that is?
*What happens when you put your ramp on carpet vs. tile?  Maybe you can measure the differences.  This is where you can mention friction and why the object didn't roll as far on the carpet though you started it in the same place.

Race away, my friends!

***Just in case you want to be challenged
Energy Equation: P.E. = K.E. + E.Losses,
so algebraically: E.Losses = P.E.-K.E.

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