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- Place the mini-marshmallows in the dish one layer thick.
- If your microwave has a rotating platform, remove it. We don’t want the dish to rotate.
- Put the dish in the microwave for 10 seconds.
- When you remove the dish, you’ll notice only certain parts are melted. (Time may depend on the microwave – if all or none of your marshmallows melted, adjust the time.)
- Measure the distance between melted marshmallows using your ruler. Measure in centimeters. This is half the wavelength of a microwave.
- Look for a sticker on your microwave that tells you its frequency in Hertz (Hz). Most microwaves are around 2450 MHz. Note: MHz = 10^6 Hz
- Use the following equation to find the speed of light: Speed of light = 2 x (distance between melted spots) x (frequency of microwave)
- The actual speed of light is 3.00 x 10^10 cm/s. How close were you?
