Main content
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
© 2024 Khan AcademyTerms of usePrivacy PolicyCookie Notice
Materials and tools
Materials
- 7 alligator clips (e.g., RadioShack #270-380 mini alligator clips)
- insulated copper wire, 22- or 20-gauge solid copper, 5 ft (1.5m)
- wooden board for base, approximately 3.5 in x 8 in (9 cm x 20 cm), can be made from 3/4-in standard shelving or plywood
- 470-ohm resistor (RadioShack #271-1317)
- 2 paper clips
- 9-volt battery
- Velcro with adhesive back, approximately 1 in x 1 in (2.5 cm x 2.5 cm), to hold the battery to the board
- 9-volt battery snap connector (e.g., RadioShack #270-325 or #270-324)
- 6 sheet-metal screws, #8 x 5/8 in
- 6 small flat steel washers (SAE #10)
- light-emitting diode (LED) (e.g., RadioShack #276-066 High Brightness Red LED)
- 2 phone plugs, 1/8 in (e.g., RadioShack #274-286 or #274-287, sometimes called mini plug; make sure you get a monoaural, not stereo, plug)
- amplified speaker (e.g., RadioShack #277-1008)
- solar cell (e.g., Edmund Scientific Co., 800-728-6999, www.edsci.com, #30398-09)
- small radio with headphone jack (e.g., RadioShack #12-799)
Note: Two premade 6-ft. audio cables with a 1/8-in phone plug on one end and two alligator clips on the other end (e.g., RadioShack #42-2421) can be substituted for the two phone plugs, about 3 ft (1 m) of the wire, and four of the alligator clips in the list of materials above. One of the cables will have to be altered slightly so that its alligator clips are far enough apart to be connected to the paper clips at screws 1 and 4.
Tools
- needle-nose pliers
- wire stripper
- small drill
- phillips head screwdriver
Want to join the conversation?
Would a laser pointer work?(4 votes)- It may not be that simple. An led would send light to the entire solar panel surface area. Whereas a laser pointer has a concentrated light beam that will only hit a small portion of the solar panel like one pixel. May not receive enough light across the entire solar panel thus would theoretically not allow it to generate enough power to push a result. Perhaps they make a solar panel or different receiver to compensate for this.(2 votes)
- Do you have to use only the radio, or maybe an iPod or any other device?(4 votes)
- iPod will also work as we just need sound and as long as you have working iPod it will be OK:)(4 votes)
Does it have to be 20 or 22 gauge?(3 votes)- What are the specs on the solar cell? The number provided links to 5 different solar cells on the edmund scientific site. Thanks,(3 votes)
- Can you explain about 5 different solar cells little bit?(2 votes)
- Can we make use Photodetector instead of solar cells?(1 vote)
- as far as i understand yes, i have been attempting this kind of experiment but using a Melles Griot silicone photodiode, light definitely does create a signal that can be picked up by basic audio equipment like you see here however I've not actually connected a laser in place where the LED was in this video (but its my intention) so i cannot confirm if the light will transfer anything that could be understood as just light alone in my unfinished set up gives back sound like raw sine waves deep ones, with fuzzing and occasional blips and beeps or similar sounds if you have ever touched a record players needle.(2 votes)
- Will a 1/4 watt resistor also work(1 vote)
- How many volts does the solar cell need?(1 vote)
when I hook up the external power source, the light will no longer fluctuate and music stops. now even without the external source the light will not come on. Is there some flaw in the design?(1 vote)
please infer how the movement of an object affects the speed of sound. tnx(1 vote)
will any battery work (excluding 6v , AA , and AAA) ?(1 vote)