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Course: Exploratorium > Unit 4
Lesson 3: Turn Light into Sound- Light into sound introduction
- Materials and tools
- Build and test the receiver
- Build the transmitter
- Construct the parallel circuit, put it all together
- What's going on: Turning sound into light
- Engineering challenge
- Turn light into sound: Complete activity guide
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Turn light into sound: Complete activity guide
Here are detailed instructions for how to build this activity at home or in your classroom. This is excerpted from the book Square Wheels...and other Easy-to-Build Hands-on Science Activities (2002), by Don Rathjen, Paul Doherty and the Exploratorium Teacher Institute.
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Quite a nice video. I have a question. ¿Could it work for transmitting sound trough water? (assuming that a waterproof canister protects the system. Thanks!(6 votes)- How about water with impurities and movement. Should be able to change the speed of light and phase shift the frequencies. Also use a slightly higher powered amplifier and an incandescent lamp. A prism might be fun too!(1 vote)
- Great demo. I tried building it and everything worked great until I hit a slight snag and I don't know how to fix it. I wired up the LED and when the battery is connected, the LED turns on. Then when I plug the headphone jack into the radio, the LED turns off. I'm not sure why the LED is turning off when the headphone jack is plugged into the radio. Please help!(3 votes)
- It's poignant: Radio Shack is no more. Where is a good source for parts?(2 votes)
Instead of a RADIO can a MOBILE PHONE or MP3 PLAYER be used?(1 vote)
Yes, you can use any source of audio signal.(2 votes)
Can you make water or air into light?(1 vote)- A microphone is a tool for converting air pressure oscillations into electric current oscillations and then we already know how to convert it into light brightness oscillations.(1 vote)
How did you know that the output phono jack on the radio providing the audio (music) would not short out the battery and 470 Ohm resistor. Is the output capacitively coupled? I would be afraid that the DC might do damage inside the radio. I really don't know what the output circuits look like in modern audio. I date way back.(1 vote)- How did you know what the proper value for the resistor was? Was there some experimental trial and error which helped you home in on the correct value? Or did you have some data sheets on the LEDs which told you the general bias area which would work well?(1 vote)
You would calculate it using the amount of volts and amperes. Study Ohm's law.(1 vote)
how can me verify that it can make much better voice to understand the words of song better without buzzing of voice(1 vote)- You could connect it to an oscillometer and visually compare input to output signal.(1 vote)
- a capacitor is needed in one input lead to isolate the input speaker from the battery dc current.(1 vote)