Light, Sound and Waves

Introducing light sources and shadows

Classroom Activity for 5-11 Supporting Physics Teaching

What the Activity is for

This activity focuses on the idea that light travels in straight lines and this behaviour causes shadows.

What to Prepare

  • several pieces of cardboard of different shapes
  • a torch
  • a screen or plain wall

What Happens During this Activity

Start with a piece of cardboard – shine a torch at the cardboard and ask the children to look what happens on the wall, and between the cardboard and the wall.

Questions to investigate:

Teacher: Does the size of the shadow depend upon where the torch shines from?

Teacher: How dark is the shadow? Is it the same darkness everywhere behind the card?

Teacher: What happens if you make a hole in the card?

A possible extension that links with the next episode is to place a stick in the ground outside. Ask children to record the length of the stick's shadow at the same time of day, on different days of the year.

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

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