Temperature Sort

Do you know what’s hot and what’s not? Test your knowledge of temperatures with this challenging activity, sure to spark some heated discussions.

  • Download, print, and cut out the cards (pages 1-6). 
  • It’s a good idea to start by sorting the temperature cards from highest to lowest.
  • Next, match up the ones you know already. Then place the rest of the ‘hot/cold thing’ cards roughly where on the scale you think they will go.
  • Try asking yourself questions to determine the order. Is the inside of the freezer hotter than the surface of the sun? Does chocolate melt at a lower temperature than that of the surface of Mars? (Probably not.)
  • If you get really stuck, page 7 of the document has the answers – but try not to look at these until you’ve had a go at matching them yourself! (Perhaps ask someone to check the answers and give you a hint.)

Curriculum Links

In addition, this activity will develop the important concept of reasonableness of numbers, which begins to develop through the Year 5 and Year 6 Mathematics curriculum.

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Flying Cup Glider

Create a fantastic flying machine in seconds and marvel at its erratic flight!

Materials

  • Two cups (paper, plastic or foam)
  • Tape
  • Rubber bands

Safety first!

  • Before launching your flying cup glider, make sure you have plenty of space around and in front of you – it’s usually safest to do all your launches outside.
  • Wear safety glasses or other eye protection when launching your glider.

Instructions

  1. Tape the two cups together at the base.

2. Make a chain of rubber bands. Start with two rubber bands overlapping each other, then loop one of them back through itself to join and pull to secure. Repeat until you have a chain long enough to comfortably wrap around the middle of your cup glider (around 15-20cm).

3. Find a safe launching area. Hold the cups in one hand, and use your thumb to hold one end of the rubber band chain against the join in the cups. With your other hand, wind the rubber bands firmly around the cups once, stretching them a little as you go. Hold the other end of the rubber band chain. You’re ready to launch!

4. Hold the cups horizontally in front of you, with the hand holding the rubber band chain slightly forward. Make sure the rubber band chain is coming out from underneath the cups, not over the top. Pull the cups back and angle your other hand up, as though firing a slingshot. Then let go of the cups at the same time as you pull the rubber band chain forwards. The chain should unwind from around the cups, spinning them in the process, which will make your amazing flying machine go!

Further investigation...

  • It might take a few tries to get the hang of launching your glider. Flicking your front hand forwards as you launch can make the cups spin faster and improve your glider’s air time.
  • Try making gliders from different types of cups and see which ones stay in the air the longest. You could also try cutting the cups into different sizes or shapes, or making a paper ‘lid’ for one or both cups to see how these changes affect its flight.
  • Experiment with different lengths of rubber band chain. Does wrapping the band around more times before launching make a difference to how well it flies?

What's happening?

There are four forces acting on any flying or gliding object as it moves through the air:

  • Lift pushes the glider upwards
  • Weight (gravity) pulls the glider towards the ground
  • Thrust pushes the glider forwards
  • Drag (air resistance) is caused by air pushing back on the glider in the opposite direction to thrust.

When you launch a glider, you create thrust as you push the glider forward and release it.

Eventually, weight overcomes lift, and the plane falls to the ground. When drag overcomes thrust, the glider stops moving forwards.

The movement of the air around the glider is also important. Although we can’t feel it, air is always pressing on us from all directions. The amount of force the air exerts on an object is known as air pressure. Air will also tend to move from areas of higher pressure to areas of lower pressure.

A scientist called Daniel Bernoulli discovered that the speed air is moving also affects the pressure – faster-moving air has lower pressure than slower moving air. This is known as Bernoulli’s principle and understanding it is very important in understanding how objects fly.

With our spinning cup glider, the fast moving air around the glider causes a difference in the air pressure above and below the glider. The air below the glider has a higher pressure than the air above it, and because air tends to move from higher to lower pressure, the air below the glider pushes it up, creating lift.

There’s also another phenomenon involved here. A spinning object moving through the air will tend to curve towards the direction it is spinning. You can see this in action in many sports – when a tennis ball is hit or a soccer ball is kicked in a way that makes it spin, it will curve or ‘bend’ in the air. This is called the Magnus effect.

Check your understanding

  1. What are the four forces that affect a flying or gliding object?
  2. Draw a diagram of your glider and use arrows to show the direction of each force.
  3. Where does your glider’s thrust come from?
  4. Why does the glider eventually fall to the ground?
  5. Explain your understanding of the following scientific terms: air pressure, Bernoulli’s principle, Magnus effect

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Myth-busting Monday: Pouncing Pepper

You might have seen this viral (ahem) video doing the rounds – a preschool teacher is using the ‘pouncing pepper’ demonstration to show her students how soaps keep germs away.

Myth: The ‘pouncing pepper’ demonstration shows how soap repels germs from our hands.

Truth: Of course, anything that gets people washing their hands more often is definitely a winner (whether or not there’s a global pandemic). And pouncing pepper is a great demonstration of a scientific phenomenon, but perhaps not the one you might think…

You can do this demonstration at home using just a few materials. A cotton tip or finger is dipped into some water with pepper sprinkled on top, and gets covered with pepper. But when the finger-dip is repeated with detergent, the pepper instantly jumps away!

So does soap repel germs in the same way it appears to repel the pepper in this demonstration? No. In truth, pouncing pepper doesn’t actually demonstrate the effectiveness of soap in removing germs.

This experiment works because of water’s surface tension. Water likes to stick to itself, and surface tension is a bit like a skin formed by the water molecules at the surface. The pepper is small and light enough that the surface tension can support it. But something bigger or heavier, like a person, can break through. You’ll know all about this if you’ve ever bellyflopped into a pool!

So how does soap affect all this?

Soaps and detergents reduce the surface tension of water – this is part of what helps them clean away oils from our hands and dishes. But the germs don’t exactly leap away.

Bacteria and viruses are partially made up of fats, which are broken down by detergents – the detergent reduces the water’s surface tension, allowing it to get between the bits of oil. Detergent is also a long molecule with one end that attracts water, and the other attracts oils. This allows the oil to mix with the water, and be washed away as you rinse.

So back to our pepper experiment. When you touch the detergent to the surface, the surface tension is reduced in that one spot. It’s a similar effect to popping a balloon – if the tension is reduced in one spot, the higher tension everywhere else pulls back from that spot, making the ‘hole’ bigger. And the pepper just helps us to see how those water molecules at the surface are moving.

So this awesome experiment is a great demonstration of how soap changes the surface tension of water, but unfortunately, germs don’t leap away from soap like the pepper does. Which means you need to keep washing your hands! Properly! Go and do it now!

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Mexican Jumping Bean

A colourful family of Mexican jumping beans made from Easter egg wrappers

Put those old Easter egg wrappers to good use in this fun activity.

Materials

  • Easter egg wrappers or aluminium foil
  • Marbles
  • Plastic container with lid
  • Cylindrical object with diameter slightly bigger than the marble’s (e.g. whiteboard marker)
Materials you will need for Mexican Jumping Bean

Instructions

  1. If you’re using foil, cut or tear it into pieces approximately 8cm x 6cm. Use a ruler to help you tear it straight. If you’re using Easter egg wrappers, smooth them out.
  2. Starting at the short edge, roll the foil around the marker, leaving about 1.5-2cm hanging over the end of the marker.

3. Firmly press the overhanging ends of foil around the end of the marker to close one end of the foil tube.

4. Slide your foil tube off your marker and drop a marble inside.

5. Carefully pinch and fold over the other end of the tube to enclose the marble, taking care not to squash the tube (the marble should have space to move around inside). Don’t worry if it’s not very neat – we’ll fix that in the next step.

6. Place the foil package inside the container, put the lid on, and shake it until the ends are rounded and smooth.

7. Roll your completed jumping bean around to see how it moves!

Further investigation…

  • Try different sizes of foil and marbles to make more beans, and observe how they move differently.
  • How does the bean’s movement change if you use several smaller balls in place of the marble?
  • Try rolling the bean down a sloping surface, such as a piece of heavy cardboard. The foil is smooth and a bit slippery – how could you make it grip the surface better?
  • Can you design a similar rolling toy made from paper or cardboard?

What's happening?

When you shake the jumping bean around in the container, the foil gets squashed between the marble and the sides of the container. This creates the bean’s smooth, rounded ends.

As the bean rolls along, the marble and the foil move separately from each other. Although it may look like it’s not moving, the marble is secretly rolling along inside the foil. The marble keeps rolling until it hits the end of the foil tube. The foil tube flips over, and the marble continues rolling until it hits the other end.

This fun experiment gets its name from an actual Mexican plant (Sebastiana pavoniana) which has a very special relationship with a species of moth (Cydia deshaisiana). The moth lays its eggs inside the seed pod of the plant, and when the larvae hatch, each one burrows inside its own seed, eats out the middle, and lives in there for several months. When the seed gets warm (e.g. by someone holding it in their hand), the larva moves around, making the seed jump in a very similar way to these foil ones!

Check your understanding

  1. Describe the push and pull forces that make the jumping bean move.
  2. On what type of surface did the jumping bean move best?
  3. How did the Mexican Jumping Bean get its name?

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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

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Hoop Glider

Picture of a hand holding a completed Hoop Glider

You won’t believe how simple this glider is to make – or how well it flies!

Materials

  • Light card or thick paper
  • Ruler
  • Straw
  • Tape
  • Scissors
  • Pencil
Materials you will need for Hoop Glider

Safety First

  • Before you throw your glider, make sure you have plenty of space around you and the glider’s path is clear (remember, it may not fly completely straight!). We recommend conducting all test flights outside, but if this isn’t possible, a straight hallway would also work. 

Instructions

  1. Cut two strips of card about 1.5cm wide, one from the long edge of the card (about 30cm long) and the other from the short edge (about 19cm long).

2. Use tape to make your strips of card into hoops. (Tip: use the smallest amount of tape possible so it doesn’t add too much weight to your glider.)

3. Tape one hoop to each end of the straw, making sure they are lined up.

4. To throw your glider, hold it with the hoops pointing up, and the small hoop at the front.

Further investigation

  • Experiment with different types of throws. What happens if you throw your glider upside-down or back to front?
  • Try making more gliders with different sized hoops or different lengths of straw. Which ones fly the furthest? Which designs don’t work very well?
  • You could even add more hoops to the same glider – how does this affect how well it flies?

What's happening?

There are four forces acting on a glider as it glides through the air:

  • Lift pushes the glider upwards
  • Weight (gravity) pulls the glider towards the ground
  • Thrust pushes the glider forwards
  • Drag (air resistance) is caused by air pushing back on the glider in the opposite direction to thrust.

These forces need to be balanced for the glider to stay in the air.

When you throw the glider, you create thrust as you push the glider forward and release it. The circular shape of the wings on the glider creates lift.

Eventually, weight overcomes lift, and the plane falls to the ground. When drag overcomes thrust, the plane stops moving forwards. To help the glider stay in the air longer, consider how you might achieve the following:

  • Increase lift – the curved shape of the wings helps create lift. Does a bigger or wider wing create more lift?
  • Reduce weight – could you use fewer or lighter materials to make the glider?
  • Increase thrust – the thrust for an aeroplane is provided by an engine, but for your glider it’s all up to you and your throwing action. How could you provide more forward force for your glider?
  • Reduce drag – flying machines and animals are usually fairly pointy at the front, so they can slice through the air more effectively. (You can test this yourself – try holding a sheet of paper vertically and dropping it, then hold it flat like a tabletop and drop it again. Which one reached the ground more quickly?) How can you improve the shape of your glider to reduce the amount of air hitting it front-on?

Sometimes, making one change can affect more than one of these forces. For example, a larger hoop-shaped wing might create more lift, but it will also be heavier and weigh your glider down. 

Check your understanding

  1. What are the four forces that affect a flying or gliding object?
  2. Draw a diagram of your glider and use arrows to show the direction of each force.
  3. Where does your glider’s thrust come from?
  4. Describe how changing the shape, size, or orientation of the glider’s wings affected its flight.
  5. Describe how changing the length of the glider’s body (straw) affected its flight.
  6. Which of your gliders worked the best? Why?

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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

  • Rainbows are very mathematical – visit this site to learn more about the maths behind how they are formed.
  • You now know that viral images such as this one, claiming to show ‘a rainbow viewed from above’, don’t show anything of the sort! This cool rainbow-coloured phenomenon isn’t necessarily fake though…it could be due to polarisation of the window glass. But that’s another story…

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Myth Busting Monday: Rainbow Shapes

A rainbow arches over a country road after rain

You can’t help but feel happy when you see a rainbow. They’ve been interpreted as divine messages, adopted as symbols of various causes and movements, and used to decorate just about anything you could imagine. So it might surprise you to learn that one of the most recognisable features of the rainbow is not actually as it seems…

A rainbow arches over a country road after rain
There is more to a rainbow than meets the eye. Image by Free-Photos from Pixabay.

Myth: A rainbow is a semi-circular arc

Truth: There is more to a rainbow than meets the eye. The semi-circular arc is simply the part of the rainbow we can see – the rest is usually obscured by the ground.

First things first – how does a rainbow form?

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.

As we know, white light is made up of lots of different colours (Red, Orange, Yellow, Green, Blue, Violet) which all have different wavelengths and therefore different amounts of energy. The colours with longer wavelengths (the ‘red’ end of the spectrum) bend less than the colours with shorter wavelengths (the ‘violet’ end). This is what causes the light beam to split into that recognisable spectrum of colours that is so familiar to us.

White light is separated into its component colours (red, orange, yellow, green, blue, violet) by a triangular prism
White light is separated into its component colours (red, orange, yellow, green, blue, violet) by a triangular prism. Image by Lucas V. Barbosa - Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=3270145

Where can I see a rainbow?

The rainbow you see depends on where you are standing relative to the light and the raindrops. The sun has to be behind you, and the rainbow will form at an angle of 42 degrees from something called the ‘antisolar point’, which is roughly marked by the shadow of your head.

(In other words, if you drew a line from the shadow of your head to your eyeball, and another line from your eyeball to the rainbow, the angle between the lines would be 42 degrees.)

This means that if the sun is lower in the sky, the rainbow will appear higher, and vice versa.

Can I go to the end of the rainbow?

The rainbow’s position depends on your eyes’ position. This means that if you move slightly, so will the rainbow that you see. And someone standing next to you will see the rainbow in a slightly different position. And THAT means that it’s literally impossible to walk to the end of the rainbow. (Sorry.)

That’s a shame. Are you going to tell me what shape a rainbow is?

Of course. Consider that 42 degree angle you drew before, between your head shadow, your eye, and the rainbow. The water drops at the correct angle from your eye to form a rainbow aren’t just in one spot. They’re in an arc, all around your eye. ALL around, meaning that if you replaced the ground with a bunch more water droplets (or your vantage point was high enough), the rainbow you’d see would be a complete circle!

Mind. Blown.

A circular rainbow over the ocean
When viewed from a high enough vantage point, a rainbow will appear as a full circle. Photo by Jakob Owens from Stocksnap.

That’s amazing! But…there’s a but, isn’t there?

Yep. But…if you’re ready to have your mind blown even further, consider this.

Rain isn’t usually two-dimensional. It doesn’t just fall in a sheet and make a line on the ground. It’s three-dimensional – and so the rainbow-forming droplets also take up a three-dimensional space.

A rainbow therefore isn’t a fixed distance away from you, the observer – it can be anywhere there are droplets of water at the correct angle. If you are unlucky enough to be standing in a solid rainstorm with the sun shining behind you, there are rainbow-forming droplets everywhere from right next to your eyeballs, to several kilometres away.

So a rainbow isn’t just a two-dimensional circle…it’s actually a three-dimensional CONE. With your eyeballs at the point, and your head-shadow (the antisolar point) at the centre of the cone’s base.

Next time you see a rainbow, make sure you inform the nearest fellow observers that it is, in fact, a rainbow CONE.

And if you’ve managed to get your head around this, head on down to your nearest ice cream shop and treat yourself to a triple-scoop cone – you have certainly earnt it.

Rainbow swirl ice cream cone
Another slightly more delicious kind of rainbow cone. Photo by Key Notez from Pexels.

Need more detail? Here is a more in-depth look at the maths behind rainbows (external link).

Use your new-found rainbow knowledge to make your own rainbow at home.