STEP 1

String Your First Cup

Using one of the paper clips or the thumbtack, poke a hole in the bottom of your first cup. Cut 20 feet of fishing line and thread one end into the cup through the hole in the bottom.

STEP 2

Complete Your String Telephone

Tie the end of the fishing line you ran through your cup to one of the paper clips. Repeat the process with the other end of your fishing line and your remaining cup.

STEP 3

Test Volume

Open Google’s Science Journal app on your phone and start a new experiment and a new test. Set the sensor to the Sound Intensity selection.

Have a friend hold one cup and talk into it in an even tone. If you want to make your test a little more accurate, use a second phone to play a continuous tone at a continuous volume into the cup instead (I like this tone generator that you can download from the Google Play store). Pull the string tight and hold the phone running Google’s Science Journal app up to the cup to record the sound levels.

STEP 4

Shorten Your String

Now that we have a base measurement from our string phone, let’s cut 5 feet of string off one end and reattach the cup.

Start a new test on your phone to record how the loss of string affects your results. Make sure you pull the string at the same tension to keep your test consistent.

Continue removing sections from your string, 5 feet at a time, and retesting.

WHAT'S NEXT?

Using a tone generator and trimming the line at set increments helps eliminate variables from your test. When conducting scientific experiments it’s important to try to keep outside factors from affecting your results, in this case we want to make sure only the length of the string is changing our readings.

How do you think pulling the string tighter or leaving it less taut would alter your readings? Will strings made from different materials change how the device performs? What other experiments can you think to try with your string phone?

Please Note

Your safety is your own responsibility, including proper use of equipment and safety gear, and determining whether you have adequate skill and experience. Power tools, electricity, and other resources used for these projects are dangerous, unless used properly and with adequate precautions, including safety gear and adult supervision. Some illustrative photos do not depict safety precautions or equipment, in order to show the project steps more clearly. Use of the instructions and suggestions found in Maker Camp is at your own risk. Maker Media, Inc., disclaims all responsibility for any resulting damage, injury, or expense.

String Phone

30 Minutes

TO COMPLETE

WHAT WILL YOU MAKE?

In this project, we'll test to see how different variables can alter the performance of a string phone. Will the sound waves transmit better when the string is tighter or looser? Create your hypotheses and then test them out.

WHAT WILL YOU NEED?

Two plastic cups
Two paper clips
Fishing line or string
An Android phone with Google's Science Journal app installed
(Optional) A thumbtack
(Optional) A second phone