Simple Science | Recycled DIY Can Telephones

We absolutely love simple science experiments for kids and lately we have been having a blast digging through our recycling bin to come up with some really fun and classic experiments. These recycled DIY can telephones are so easy to make but provide so many awesome opportunities for science learning.

Simple Science for Kids Recycled DIY Can Telephones

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We have always been big fans of recycled projects and classic science experiments, so it comes as a surprise that we had never tried this simple science experiment.

As always, instead of just doing a demonstration, we added a little bit of testing to the activity to make the learning stick and more concrete!

How to Make DIY Can Telephones

Materials for DIY Can Telephones

Materials for DIY Can Telephones

Recycled Soup Cans
Duct Tape (optional)
String of Varying Sizes and Thicknesses
Toothpicks or Paperclips

Basic Steps for Making DIY Can Telephones

How to Make DIY Can Telephones

Making DIY can telephones is actually quite simple. It is simply 3 easy steps that anyone can do. decorating your cans adds a step but makes it a bit more fun for you and your kids.

Start by wrapping your clean cans with your choice of duct tape. Now is a great time to have an adult cut a hole in the center of the bottom of the can. This can be done with a knife, scissors, or wire cutters.

After tying a string of your choice to a toothpick or paperclip, thread the string through both holes in the cans and you are ready to go. See… easy.

Simple DIY Can Telephone for kids

Now… What kind of string? How long should the string be? Does it matter if I use a toothpick or paperclip? Great questions! Now you have an experiment!

Testing Variables for the Best DIY Can Telephone

You see, making a telephone is awesome. It is a great way to demonstrate how sounds vibrations travel from one place to another. What’s even more fun, though, is to encourage children to come with their own discoveries about how the world works. This can done simply by encouraging them to ask questions and find answers to simple experiments just like this one.

Making DIY Can Telephones with kids

There are endless possibilities you can try. We made two sets of telephones so we could change one variable at a time and listen to both at the same time.

We started by experimenting with 2 short strings of different thicknesses. What do you think carried sounds better… the yarn or the string?

Testing different strings for DIY Can Phones

Then we tested the taughtness of the string. What do you think worked better… keeping the string tight or giving slack in the line?

Testing different strings for DIY Can Phones

Finally, we tested length of the string. Which one do you think carried sound better… a long string that stretched across the living room, or the short string that went across our kitchen table?

This wasn’t the end of our desires to experiment with variables. Remember how I told you we used toothpicks. We are super curious what would happen if we changed them out for paperclips. Would it make the sound vibrations travel further? Is the wood absorbing the vibrations? Only one way to find out…

Testing Variables with Recycled Can Phones for Kids


This post is a part of an amazing series of hands-on STEM activities for kids. I’ve joined up with 28 other bloggers and we’re creating 60+ fun science, technology, engineering & math activities. Each week is a different topic: STEM Goes Green, STEM Challenges, Coding for Kids & STEM On the Cheap.  Click here for the full list of activities.




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5 thoughts on “Simple Science | Recycled DIY Can Telephones”

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