Light as Energy
Materials
Light up stick
UV beads
No Preparation
What to do
Show the students the light up stick and ask if they know what it is.
Ask if the light up stick is glowing right now. You may want to pass the stick around and have them shield the stick in their
hands to observe.
Ask what is in the stick. (“Chemicals” is a suitable answer).
Explain that there are a couple of different kinds of chemicals. One kind is inside a thin glass tube and another kind surrounds
it where we can see it. What will happen if we break the thin glass tube by bending the stick?
Help the students to recognize that a chemical reaction will take place.
So what energy transformation is taking place?
Chemical to Light
If it is a sunny day, you will be able to get the UV beads to work well. They will work on a cloudy day but not as dramatically.
Show the students the UV bead and ask what color it is. (white)
Have a student take the bead to the window to observe the color change. This will take longer on a cloudy day. Why does
this work in sunlight but not the regular room?
Sunlight contains Ultra Violet, or UV light that is higher energy than light from the light bulb.
So what energy transformation is taking place? Remind students that color changes often accompany chemical changes.
Light to chemical
Questions
What energy transformation was observed in each case?
What living thing also changes light energy to chemical energy?