Friction: sliding blocks down ramps

Students slide blocks down ramps and compare different surfaces for different amounts of friction
Science content
Physics: Motion and Forces, Newton’s Laws, Gravity (K, 2, 6)
Lessons activity is in
  • Set of cardboard ramps
  • Set of of blocks, a matched pair for each pair of students (tested for same speed down ramp)
  • Set of blocks to hold up the end of the ramp
  • Set of cloth strips, cut to fit half of the ramp
  • Set of sandpaper strips, cut to fit half of the ramp
  • Set of clips to attach the materials to the ramp
  • Set of recording sheets

Students, in pairs, will slide blocks down different materials at their desks, to test different materials for the amount of friction.

Explain procedure: Set up your cardboard ramp, and slide two blocks together, to test out your set up. They should go down at about the same speed. Then clip different materials onto the ramp, and compare the friction of each of the materials by sliding a two blocks down at the same time. Slide the blocks a few times to make sure you are getting a good result.
Compare cardboard and cloth. Then try cloth and sandpaper. Then sandpaper and cardboard. (Optional: compare ice with the other materials.)
Each time, record which material has the most and which has the least friction on your worksheet.

If students get done early, they can change how the ramp is set up e.g. height, and try sliding blocks again.

Summarize what kinds of surface increase and reduce friction (5 mins)
Ask students to bring their cardboard, cloth and sandpaper to the carpet.
Which surface had less and more friction for each pair?
Feel the surfaces and talk about why they have the least and most friction.
Bumpy surfaces rub against the block more, and slow it down more.
Write on board: under less friction put smoother surface, under more friction put bumpier surface.

Grades taught
Gr K
Gr 1
Gr 2