Kathleen -
Sounds like a good setup. In terms of the construction, you may
want to consider using 2 flat boards with a hinge in the middle and
something to hold the top one up. If you have problems with the ball
rolling off the side of the board, try giving it guard rails using
cardboard or 2 smaller boards. A regular protractor should be fine to
measure the angle of inclination with. Also, you may want to consider
using a racketball or a tennisball instead of a golfball because
golfballs have an uneven surface which may affect your results.
As for different surfaces, it's a lot more straightforward than it
may seem. In addition to just rolling the ball down a flat board, you
can try covering the board with sandpaper, wax paper, and other things
which will provide more or less friction. Make sure that if you do
this, though, you should do your tests for each surface by using the
same set of angles. (I.e. do sandpaper at 20, 40, 60 degrees, wood at
20, 40, 60 degrees, and wax paper at 20, 40, 60 degrees.) This way,
you'll be able to compare them more easily.
The other thing which may be worth looking at is starting the ball
at the same /height/ while changing the angle of the board. You can do
this by standing a ruler up next to the board and starting the ball at
say 10 inches up from the table regardless of the angle of the board
it's rolling on. I think you'll find that the results of this will be
pretty interesting.
And as always when doing scientific experiments, make sure that you
do every test more than once. (For example, using sandpaper at 40
degrees, measure the distance that the ball will roll at least 3
times.) This way, if something goes wrong in one test, you'll be able
to tell by looking at the other values you've collected. 3 or 4 tries
for each scenario should be a good number. Then you can average these
values to get an even better one.
Good luck!
-Tamara
(published on 10/22/2007)
