Coat Hanger Gong

Use an everyday wire coat hanger to make some very strange sounds!

Materials

  • Wire coat hanger
  • Two pieces of string about 40-50cm long

Instructions

  1. Tie the pieces of string to the two bottom corners of the coat hanger.

2. Wrap the other ends of the strings around your pointer fingers and put your fingers in your ears.

3. Gently swing the coat hanger so that it hits something solid (for example, a table) and listen to the sound it makes.

Further investigation

  • Try swinging the coat hanger into different things. Does a table sound the same as a couch?
  • Ask a friend to tap the coat hanger with objects made from different materials. Does it sound the same when a finger and a spoon taps the coat hanger? 
  • Repeat this experiment using something else instead of the coat hanger. Try a metal spoon. Does it work as well with a plastic coat hanger?

What's happening?

When you tap the coat hanger onto a table normally (without fingers in your ears), the coat hanger vibrates and makes the particles in the air next to the coat hanger vibrate. The vibration is passed from one air particle to the next to the next to the next. This is a called a sound wave. If this sound wave moves into your ear and starts vibrating your ear drum, you can hear sound. 

But the particles inside the coat hanger start to vibrate as well. And this vibration is passed from one coat hanger particle to the next to the next to the next. Then the vibration passes into the string and the string particles vibrate. The vibrations travel up the string and directly into your ear.

It sounds louder because sound can travel more easily through a solid than through the air. The particles in a solid are much closer together compared to the particles in the air.

This is why it will sound louder to someone that is directly connected by the solid string to the coat hanger, than someone who hears the sound through the air.

You can also experience this with a cup and string phone. Tie a string to the bottom of two paper or plastic cups. One person speaks into one cup while the other listens through the other cup.

Check your understanding

  1. Describe the sounds the coat hanger made, both before and after you put your fingers in your ears. How were the sounds different?
  2. How does sound reach our ears?
  3. Why does putting your fingers in your ears in this experiment make the coat hanger sound louder?
  4. What makes the loudest sound? Which sound do you like the best?
  5. Explain your understanding of these scientific terms: vibration, sound wave

Curriculum Links

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Popstick Harmonica

Two completed Popstick Harmonicas

Make a fun musical instrument using a few simple materials. 

Materials

  • 2 popsticks (large ones work best)
  • 2 small rubber bands
  • 1 straw
  • 1 wide rubber band
  • Scissors
Materials for making popstick harmonica

Instructions

  1. Cut two pieces of straw about 4cm long each.

2. Stretch the wide rubber band over one of the popsticks.

3. Slip one piece of straw under the rubber band, a few centimetres from one end.

4. Place the other popstick on top and wrap one of the small rubber bands around the end where the straw is. The rubber band must be outside the straw.

5. Place the other piece of straw between the two popsticks a few centimetres from the other end, but this time on top of the wide rubber band. Secure with a small rubber band.

6. To play your harmonica, put the popsticks in your mouth (between the straws) and blow. The large rubber band vibrates between the popsticks to create the sound. (You might need to squeeze the popsticks together a little bit.)

What's happening?

When you blow through the harmonica, the rubber band vibrates and you hear a sound.

When the straws are closer together a smaller length of the rubber band is vibrating. This makes the rubber band vibrate faster, and you hear a higher pitch.

When the straws are further apart, more of the rubber band can vibrate. This slower vibration allows us to hear a lower pitch.

How fast or slow something is vibrating is called the frequency.

Check your understanding

  1. Which part of the harmonica is vibrating to make the sound?
  2. How does moving the straws change the sound of the harmonica? How would you describe the sound?
  3. Explain your understanding of these scientific terms: vibration, pitch, frequency

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Make a Rainbow

A rainbow forms in the fine spray from the hose

A rainbow is often a welcome sight when the sun comes out after a rain storm. Find out how to make your own rainbow when there’s not a cloud in sight!

Materials

  • A sunny day
  • A hose with a mist attachment
  • An open sunny space, such as a back yard

Safety first!

  • Always be sun smart when outside during the day – wear a hat, sunscreen, and clothing that covers as much of your skin as possible. 
  • It’s safest to stay in the shade in the hottest part of the day – fortunately, this experiment works best when done in the morning or afternoon.
  • Be aware that the wet ground might be slippery. Consider doing this experiment on a grassy area or near a garden so the water you use won’t go to waste!

Instructions

  1. Stand in your sunny space with the sun behind you. You should be able to see your shadow in front of you.

2. Turn on your hose. If your hose attachment has a choice of nozzles, choose the one that makes the water drops the smallest – for best results it should be a fine mist.

3. Move the spray around in front of you until you see a rainbow form in the droplets!

A rainbow forms in the fine spray from the hose
Get the angle just right, and you'll see a rainbow form in the fine mist from the hose!

Further investigation

  • While looking at your rainbow, try moving to a different spot in your sunny space. Does the rainbow appear in the same place it did before?
  • If you are doing this experiment with a friend, get them to stand a short distance from you. Can they see your rainbow too? What if they have a turn with the hose and make their own rainbow – can you see it from where you are? 

What's happening?

A rainbow forms when sunlight hits small drops of water in the air. Water is denser than air, so the light slows down and bends (refracts) a tiny amount when it enters the water drop. The light bounces around inside the raindrop, then exits again at a different angle.

White light is actually made up of lots of different colours mixed together, but our eyes see them as six distinct colours – red, orange, yellow, green, blue, and violet. Each of the different colours that make up white light bends a slightly different amount inside the water drop. When the light exits the water drop, each of these colours shows up as a distinct band.

The location of the rainbow that you see depends on the angle between your eyes, the sun, and the water drops. When you moved, your eyes (hopefully) moved along with you – and therefore, so did your rainbow. Someone standing in a different spot in your back yard won’t see the rainbow in the same place you do – they might not even see it at all!

When you see a rainbow in the sky, there are usually many more water drops than you can make with your hose, so lots of people can see it at the same time. However, everyone will see it in a slightly different place depending on where they are standing. And unfortunately, this means that it’s impossible to visit the end of a rainbow. (Sorry.)

More on this topic

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Bang! Crash! Smash! Science!

Our Year One workshop focuses on the Australian Curriculum concept that “Light and sound are produced by a range of sources and can be sensed”.

So it’s probably little wonder that this is the noisiest of all our workshops, discovered recently with the help of the Year Ones of St Mark’s Primary School in Inala.

The children enjoyed making as much noise as possible with our great range of instruments and noisy everyday objects.

Children making noise in the name of scienceMore scientific noise-making

 

 

 

 

 

 

 

 

 

As well as the noisemakers, the workshop includes experimenting with light, colours and optical illusions. And they all got to try on the latest scientific fashion accessory – rainbow glasses!

Everyone wearing rainbow glasses

(It’s hard to tell from the picture, but the lenses of the glasses split light into rainbows, so everything the wearer looks at is edged with rainbow colours.)

They also had the chance to experience a bug’s-eye view of the world.

Bug's eye view

 

Thanks St Mark’s, we had lots of fun visiting your students!

Our Year One program isn’t the only one that focuses on the Australian Curriculum learning outcomes – in fact, all of our school programs do! Contact us to find out more about bringing a fantastic curriculum-based science lesson to your school.