Students discover how an ultraviolet (UV) LED can make a fluorescent pattern glow in the dark. Then they learn about how different forms of radiation are related, including ultraviolet, visible and infrared light.
Things that glow: Demonstrate how to light up a secret message using a UV LED.
If possible, have someone turn off the lights so the effect is more dramatic. Conduct a discussion about what is happening:
Make something that glows in the dark: Provide materials and time for students to make their own images and messages that can glow in the dark.
Different forms of radiation: This lesson uses ultraviolet (UV) light and the next one will focus on infrared (IR) light, so this is a good opportunity to discuss different forms of light and of other kinds of radiation (see a video). Ask students:
Chart their observations. Explain that these are all forms of radiation, and ask:
* What other forms of radiation are there?
* How is each type of radiation produced?
* What can it be used for?
If the secret message or image glows but is too dim, some things to try are:
If the UV LED doesn’t come on at all, check to see that the batteries are stacked correctly (see a video). To learn more about this issue, you can use the Digital Multi meter – click here to explore further.