Rainbow with water and flashlight

Shine a flashlight through water at just the right angle to make a (subtle) rainbow.
Science content
Physics: Light and Sound (1)
Earth/Space: Weather, Seasons, Climate Change (K, 1, 4, 7)
Lessons activity is in
  • jar half filled with water
  • flashlight
  • white sheet of paper

Distribute glass of water, flashlight and white paper to each student or student pair.
Ask them: We have water and sunlight. What weather feature might we make?
Once they know they are looking for a rainbow, older students can be challenged to arrange the flashlight, jar and paper to make a rainbow, while younger students can be assisted in making one:
Hold the jar in the air just above the desk. Lay the paper down in front of the jar. Shine the flashlight at the water line from back a bit, maybe angling it downwards a little. Don't block the bottom edge of the jar with your fingers. The higher the jar, the wider the rainbow. If you tip the jar slightly, you can make multiple rainbows.

Grades taught
Gr 1
Gr 2
Gr 3
Gr 4
Gr 5
Gr 6
Gr 7