Reflection
Light, Sound and Waves

Reflecting a ray of light and a rubber ball

Practical Activity for 14-16 PRACTICAL PHYISCS

Demonstration

Comparing the paths of a reflected ray of light and a rubber ball.

Apparatus and Materials

  • Light source, compact (100 W 12 V)
  • L.T. variable voltage supply (12 V 8 A)
  • White screen (500 mm x 300 mm approx)
  • Card with slit (5 mm wide approx)
  • Retort stand and boss
  • Plane mirror
  • Rubber ball

Health & Safety and Technical Notes

Be aware that compact light sources using tungsten-halogen lamps without filters are significant sources of UV. Ensure that no-one can look directly at the lamp.

Read our standard health & safety guidance

Procedure

  1. Set up the compact light source with the card and slit in front of it, so that a thick ray of light splashes across the vertical white screen.
  2. Catch the ray with a piece of plane mirror held in the hand and reflect it across the screen.
  3. Bounce the rubber ball against a hard wall or floor to show its reflection.

Teaching Notes

  • This demonstration introduces the idea of reflection. It is not intended for careful measurements, but students should see some connection between the angles.
  • Make sure that students observe the similarity between the path of the ray of light, and the path of the ball.
  • You could ask the question 'What is light made of... bullets?'. If students have seen waves being reflected in a ripple tank, they might also give waves as an answer.

This experiment was safety-tested in August 2006

Reflection
is formalised by Law of Reflection
can be exhibited by Progressive Wave
has the special case Total Internal Reflection
IOP AWARDS 2025

Teachers of Physics Awards

The Teachers of Physics Award celebrates the success of secondary school physics teachers who have raised the profile of physics and science in schools. Nominations for 2025 are now open.

Start your nomination now