Good Vibrations

Sound waves are a form of energy (Photo by Jason Rosewell on Unsplash)

Age group 3rd – 6th class
Total time: 30mins

Outline: To learn about how sounds are made and how they travel through different materials

Links to Primary Curriculum Key Learning points

The child should be enabled to
learn that sound is a form of energy (Area: SESE, Science:  Forces and Energy,Sound)
explore how sound travels through materials (Area: SESE, Science:  Forces and Energy,Sound)

Sound is a form of energy
Sounds travels as a wave
Sound travels better through more dense materials

Notes for parents/carers and teachers

This activity can be carried out at home by a child/small group of children and an adult, by varying the types of age-appropriate tasks. The materials are available at home or easily obtainable. The activity is written out with instructions directed to the child’s parent/carer. Feel free to adapt this activity as appropriate.

1. What do you know about making noise?

Spark the children’s curiosity by asking some questions like the following:

Do you know what happens when you shout or when you whisper? Do you think it takes more or less energy to shout? How do you think sounds move from one place to another?

NOTE: For younger children, feel free to carry out the experiment first and then ask them some questions about what they think happened after.

Introducing them to the experiment:

Start with saying something like “ Every time we open our mouths to speak we are creating lots of sound energy! We know that sound energy can travel through the air until another person hears it. Do you think sound energy can travel through a wall? through water? Think about when you may have heard sounds through different types of materials. Do you think sound energy can go faster in the air or in a piece of string? Want to find out? Let’s experiment….

Feel free to add these interesting facts into the conversation.

Did you know?

  • Sound travels through dry air the slowest. It hits speeds of 343 meters-per-second. This means it can go one mile (1.6 kilometers) in around five seconds.
  • There is no sound in space because there is nothing for it to bounce off
  • The voice of a whale can travel up to 800 kilometers (479 miles) through the ocean waters!

2. Making your paper cup phones

What you need

Use reused/recycled materials where possible (washed coffee cups)

2 paper cups, Long string (5m approx) like fishing line, kite string, A sharp pencil or needle to poke holes in the cups, paper clips, scissors


1. Cut a long piece of string of at least 15 metres in length. (This experiment will work with string up to about 30m in length)

2. Poke a small hole at the bottom of each cup, with the pencil/needle.

3. Using each end of the string, thread it through the bottom or each cup, tying a large knot on the inside of the cup, so the string does not fall out of the cup. If you make the holes too large, use a washer or paper clip to hold the string in place so that it does not pull out of the cup. 

4. While you hold one cup, have your child hold the other cup and ask them to move away from you until the string is taut (pick somewhere with enough room). The string must not touch any other object. Make sure the string remains suspended and taut until you complete the experiment. 

5. Taking turns talking into the cup, while the other person listens by putting the cup to their ear. Tell your child to repeat what she/he hears after you have spoken and do the same in return! Try talking at different volumes, down to a whisper, and see how much the other person can repeat. Try using different sounds, like a bell or music from a phone, and see if the other person hears them at the other end. Try talking at a normal volume without using the cup and see if the other person can hear you better or worse across the same distance. Why is that?

6. If you are up for more, try string of different length and see how well it works.

3. How does this work?

Prompt the children with some questions like these below. You can then read the full explanation to them, or better still, put it into your own words.

Key questions

How do you think the sound got from one person to the other? Could you hear each other better with or without the paper cup telephone when you tried speaking at normal volume? Do you think this could work as a phone inside your house? Why?


Sounds are produced from anything which is vibrating. It takes energy to make vibrations so sound is a form of energy. These vibrations (or sounds) can travel through any solid, liquid or gas (like air) as a type of wave. Though sound waves can travel through air, solid and liquids carry sound better or more effectively, because they are more dense (their particles are closer together).

When we speak, we cause the air in front of our mouths to vibrate. Speaking into the cup transmits the sound of the speaker’s voice into the bottom of the cup. The bottom of the cup acts as a diaphragm and vibrates with the sound of the speaker’s voice. As the bottom of the cup vibrates, it transmits the vibrations into the taut string. The sound travels along the string as a wave and ultimately vibrates the bottom of the receiving cup. The cup transmits the sound into the air around the listener’s ear, allowing her to hear the speaker. Because the sound travels through solid mediums – the cup and the string – it travels more effectively than through air, allowing the users to communicate across large distances with volumes that would be inaudible if spoken through air.

4. What did you like? What did you learn?

What did you most like/least like about this activity? 

What did you learn about sound energy? 

What else would you like to learn about sound?

5. Dorte Hammershøi and the Story of Sound

Dorte Hammershoi is a Danish professor in electronic systems. She works in the field of human-sound perception, which includes electro-acoustics, hearing damage and the measurement of noise sources close to the ear. She investigates how hearing aids can be improved in order to help people with hearing problems. She is developing tests to see how well the human ear can hear words even in noisy places. This really helps to understand how well someone’s hearing is working or not.

6. Extra Resources

Kids Academy is a site for parents and educators for young learners with worksheets, games and more!

Sciencing is a site for students for science and maths homework help, project ideas and science news on how science affects our every day lives.

The Science for kids club site is a free science network for kids with quizzes, games, videos and more

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