Wednesday, July 2, 2014

Ramps: How Does Oil or Molasses Change the Surface of a Ramp?

Inclined planes are simple machines that help us move objects.  Inclined planes or ramps are used all around us- at the playground (slides), stores (ramp), and our homes (gutter downspout).  But what happens when the surface of a ramp is damaged or changed?  Jelly Bean and Jumping Bean tested this out by creating a ramp and then changed the surface by coating it with oil and molasses.



We created ramps by using metal cookie sheets with one end raised on a stack of books.  With the first ball of play dough, the girls dropped it on a clean cookie sheet.  It just stuck to the cookie sheet.


I asked them how we could make the play dough slide down the cookie sheet easier.  They both knew right away to pour oil on it because the oil acts as a lubricant


Boy, did it slide down the cookie sheet fast!

Next, the girls wanted to see what would happen if we added something sticky.  We looked through the cabinets and found molasses. 


The girls thought the play dough would just stick there and not slide down, but it did- very slowly. 


We wanted to compare the two liquids so we raced the play dough balls down each side of the cookie sheet.  One side still had the oil on it, and the other side still had molasses on it.  It wasn't even close, the oil made our ramp much more slippery and much faster!

**********
Supplies:
  • play dough rolled into 3 balls
  • cookie sheet
  • books
  • oil
  • molasses or other sticky liquid
Instructions:
  1. Place one end of the cookie sheet on a stack of books to create a ramp.
  2. Roll play dough into 3 balls.
  3. Drop one ball onto the clean cookie sheet and discuss what happens.
  4. Pour oil onto one side of the cookie sheet.
  5. Drop ball onto oil and note how fast the play dough slides down the ramp.
  6. Pour molasses onto the other side of the cookie sheet.
  7. Drop ball onto the molasses and note how slow the play dough slides down the ramp.
  8. Take each ball and drop them onto the oil and molasses at the same time.
  9. Compare how fast or slow each ball of play dough moved.
**********

No comments:

Post a Comment

Thank you for your comment.