Microwave Lightbulb

Thursday, 8 March 2012 0 comments
Make a metal filament glow from microwaves, not electricity
Microwave Lightbulb

We love to see what microwaves do to common household items. We've shrunk potato chip bags and turned Ivory Soap into a fluffy soap souffle. What more could we want to do? We heard that it's possible to actually make a lightbulb light-up if you do it right. And sure enough, we figured it out.


  • Incandescent lightbulb (has a tungsten filament)
  • Microwave
  • Water
  • Small microwave-safe cup or glass
  • Heavy glove
  • Adult supervision


Before we tell you anything about the experiment, you need to do two very important things: 

  1. Get permission from an adult to conduct this experiment and use a microwave. 
  2. Ask an adult to supervise your experiment. 
Done those two things? All right, let's do this!
  1. If the microwave you are using has a rotating tray on the bottom, go ahead and take it out. Don't throw it away because you'll want to put it back. We just don't want it in there right now.
  2. Grab a small (no taller than a lightbulb) microwave-safe cup or glass and fill it one-half full with water.
  3. Place the lightbulb, socket-end first, into the glass of water and set the glass in the center of the microwave.
  4. Close the door of the microwave and set the time at 45 seconds. We're serious! DO NOT SET THE MICROWAVE FOR ANY LONGER THAN 45 SECONDS! THIS IS A SAFETY HAZARD!
  5. Stand back and watch what happens.
  6. Before removing the glass and lightbulb from the microwave, allow them to cool and use a heavy glove.

How does it work?

For a moment, you might have thought that the lightbulb was going to explode in a flurry of glass shards and metal. Luckily it didn't (that would be a lot of clean-up). The lightbulb doesn't explode because you are shielding the bulb from the full effect of the microwaves by covering the metal end with water.
The microwaves do, however, pass through the glass of the lightbulb to excite the tungsten filament inside. The tungsten is thin enough that it glows when excited by the microwaves. This is the same thing that happens when an electrical current, like the one from a light socket, passes through the tungsten filament
From: Stevespranglerscience.com


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