You’ll need

  • Scissors
  • Empty toilet or food wrap rolls
  • Milk cartons or other small cardboard boxes
  • Magnets
  • Tape
  • A vertical magnetic surface, such as a fridge
  • A few plastic balls (small enough to fit through the toilet rolls)

What to do

  1. Cut the toilet or food wrap rolls in half lengthwise.
  2. Cut the milk cartons or cardboard boxes in half lengthwise and cut the ends off.
  3. Tape the fridge magnets to the sides of the rolls, milk cartons and boxes.
  4. Stick the pieces of rolls, milk cartons and boxes to the magnetic surface.
  5. Form a track that the ball can roll down.

Questions to ask

Can you make the ball roll faster or slower? Try changing the angle of the track. Move the pieces to make the ball move faster or slower, or try to direct it to specific places on the floor.

What happens if you use something other than a ball? Try using a toy car. What moves faster? Do they make different sounds?

What happens if you change the number of pieces of track? Try taking away some pieces to make a shorter track or adding pieces to make a longer track.

What's happening

Gravity can be hard to understand for kids. It is the force pulling the ball or other object to the ground. This activity shows kids that the ball rolls faster when the track is steeper and slower when it is less steep.

If you make the track shorter, the ball will reach the ground sooner.