Conservation of Momentum
Forces and Motion

Resting Egg

Enrichment Activity for 5-11 11-14

What you need

  • A broom
  • A glass
  • An egg
  • A paper plate
  • An empty toilet paper roll


  1. Fill the glass half-way with water and set it near the edge of a counter or table.
  2. Place the paper plate on top of the glass, with the edge of the plate slightly over the table edge. Stand the toilet paper roll in the middle of the plate, making sure that it's over the centre of the glass. Place the egg on the toilet roll.
  3. Stand with the broom next to the table edge, with the handle in front of the plate. Place one foot on the bristles, bend back slightly, then let go!

Results and Explanation

When the broom hits the plate, the plate and toilet roll are knocked away and the egg falls into the glass, because it is not moving sideways as the plate and toilet roll move away. Objects do not start to move in a given direction unless acted on by an external force in that direction.

Conservation of Momentum
is expressed by the relation m_1u=m_2v
is used in analyses relating to Collisions
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