Science Buddies: "Ask an Expert"

My son is making a mobile of the solar system and he wants the sun to actually light up. His idea was to purchase a 40 watt, 4 inch diameter round bulb and paint it with glass paints. I am afraid of painting bulbs. Does anyone know if this can be safely done? If not, what about permanent markers such as colored Sharpies? Do you have any suggestion that would be easy for a 7 year old to implement? He saw the light-up kits that you can purchase, but he must do this on his own....no kit.

Thanks for any suggestions you can offer!

An interesting problem - how to safely provide "solar illumination" for a solar system display. Here's my thoughts and suggestions:
- A lightbulb wired to 120VAC power could be a nuisance to install as extension cords and some sort of rigging would probably be required. Quite a bit of heat is generated by the bulb, as well, so painting it could present problems, as could getting construction material (lighweight tissue paper?) near it (possible fire hazard).
- I think a more practical solution would be to find a small battery-powered light such as can be found at a local drug store. The chances are good that the display would only need to be powered for a fairly short time, perhaps an hour or so, and a pen-cell powered light would be lightweight and the batteries could readily be replaced if necessary.
- A small battery-powered light could be quite compact and still illuminate a fairly broad area, such as a bicycle warning light that I've seen on occasion. This could be worked into a simple display model of the sun to convey the point that the sun is radiating sunshine -

I hope this helps and good luck!

Peter Young

Thank you for the reply, Mr. Young.

This is my Son's first Science project and he has some really neat ideas, but isn't too sure how to implement them. I am trying to guide him in a way that will lead him to the answers he needs with minimal input from me. I think if I take him shopping and we happen to "find" these small lights that you mentioned, he should come up with his own ideas on how to use them. Thanks again for your help!