PSA Microgravity Challenge
Caroline Robins Community School, Canada
Mrs. Liebrecht’s Grade 4/5 class
By: Jenna, Rochelle, Chelsea and Nicky
How our PSA works: We cut out and taped two pieces of
cardboard and stuck them on to opposite ends of the remote controlled
skateboard. Then we stuck two strings into the tennis ball and tied
the two ends through the pieces of the cardboard. With the remaining
piece of string, we held the end of the string and let it go. This
caused the tennis ball to lift up 3 inches. We can easily move the
PSA forward and back by the use of the remote controlled skateboard.
Questions from Expert Dan Andrews with Student Responses:
This is a very nice diagram, and I think I
sort-of understand how it works. If I push on the PSA (ball) the skateboard
will begin moving.
Actually, it is not a matter of pushing on
the PSA. You can easily move the PSA forward and back by the use of the
What if I push the PSA sideways, though? I don't think
the skateboard could move in that direction, so the PSA couldn't move.
The skateboard does not move side to side, but the
string attached to it allows one to accomplish that task manually.
What if I pulled-up on the PSA (Ball)? Would it keep
moving up, or would it fall back down as soon as I let go of it?
If you let go of the PSA it would fall down once you
let it go. This is one problem we are stilling figuring out.