marvin and milo parte a

What you need

Two polystyrene cups

Two large elastic bands

Sticky tape

Instructions

1. Tape the two polystyrene cups together at the base.

2. Tie the two elastic bands together. 3. Hold one end of the elastic where the cups join and wind it around a few times until the

other end of the elastic is at the bottom and pointing away from you. 4. Hold the cups in one hand and stretch the elastic with the other. 5. Fire the cups like a catapult.

Results & explanation

Once you've had a bit of practice, the cups will soon be looping in the air.

This is because elastic makes the cups spin backwards as well as move forward through the air. This back spin creates lift, forcing the cups upwards. But air resistance soon slows the cups down and they fall towards the ground, completing the loop.

What you need

A cone shaped party hat

Scissors

A soft ball

A friend

Instructions

1. Cut the tip off the party hat to make a hole about 2cm in diameter.

2. Wear the hat over your face. 3. Try to play catch with your friend using a soft ball.


When you’re wearing the hat you can only see with one eye at a time. Without your normal, two-eyed, binocular vision you can’t judge distances as well and it’s much harder to catc h the ball.

What you need

A balloon

An empty pop can (aluminium cans are best)

Instructions

Tell your friend you can make the can roll along without touching it or blowing it

Place the can on its side on a flat surface

Rub the balloon really fast against your hair or a woolly jumper.

Hold the balloon close to the can. The can will start moving towards the balloon.

Slowly move the balloon away from the can and the can will follow it.


When you rub the balloon against your hair, electrons are transferred from your hair to the surface of the balloon, so that it becomes negatively charged.

When you hold the balloon close to the can the negative charge causes the electrons in the can

to move away ( they are repulsed by the negative charge, because they are negatively charged themselves). This creates a positive charge on the surface of the can, so that now the can is attracted towards the negative charge on the balloon.

This trick works well with a pop can because it's light, so it will move with a small force applied to it, and because in a metal it is easier for electrons to move around.

What you need

- Kitchen towels

- Water

- Non-permanent coloured felt tip pens

Instructions

1. Draw a dot in the centre of the kitchen towel with a felt tip pen. Black works well, but you can experiment with other colours.

2. Add a few drops of water to the dot.


As the water spreads through the tissue, the coloured pigments that make up the ink separate out.

The differently coloured pigments are made up of different-sized molecules. This means that the water can carry them different distances across the paper.

What you need

Two identical paper or plastic cups

Instructions

1. Take two empty cups and put one inside the other. 2. Hold them quite close to your mouth and blow between the rims of the cups


If you blow softly the inner cup rises up slowly. If you blow hard the top cup launches itself across the room.

Moving air has a lower pressure than still air, so, as you blow, you lower the air pressure between the rims. As the still air in the bottom of the cup is at a higher pressure, it forces the top cup up and out.

What you need

uncooked rice

a pencil a large empty jar with a narrow neck

Instructions

Fill the jar to the brim with uncooked rice (make sure you have a jar that narrows towards the top)

Push the pencil right into the rice

Stab the rice repeatedly, alternating between shallow and deep stabs. It could take up to 40 stabs, but you'll start to feel the pencil gripping the rice.

When you feel a firm grip, carefully lift the jar by the pencil.


The pencil lifts the jar

As you push it in, the pencil forces the grains sideways, but they fall back into the gap as you try to pull it out. The rice becomes more and more tightly packed until the friction between the rice and the pencil is so great you can lift the jar.

What you need

1. A large clear, straight-sided glass 2. water 3. milk

4. teaspoon 5. torch 6. darkened room

Instructions

1. Fill the glass about two thirds full of water

2. Add half a teaspoon of milk and stir 3. In a darkened room, shine the torch down onto the top of the water while looking

through the side of the glass. Can you see the blue colour?

4. Now try shining the torch through the side of the glass while looking through the opposite side. What colours can you see now?

5. Finally, shine the torch up through the bottom of the glass and peer down through the water.


While shining the light up through the bottom of the glass, you should see a 'homemade sunset'. The milk particles in the glass scatter the light in the same way that dust and particles in the Earth's atmosphere scatter light from the sun. The further the light has to travel through the

water, the more of the blue light is scattered, leaving only red light for you to see, just like at sunset.

What you need

An empty fizzy drink can

Some water

Instructions

1. Pour about 100ml of water into an empty fizzy pop can.

2. Tip it slightly to one side and balance it so that the two parts of the bottom rim are touching the table.

3. Once the can is stable, give it a gentle push and it will pirouette!


For something to balance, its centre of mass has to be above its point of support. Water can flow which means that as the can pirouettes, the water moves and the centre of mass always stays above where the rim touches the table.

What you need

1. Two very similar books, with at least 100 pages each.

Instructions

1. Carefully, and evenly, interweave the pages of the books son that they overlap to about

the middle of the page. 2. Hold the books by the spines and pull!


Friction is the force that acts against the motion of two surfaces in contact. The friction between the just two pages is tiny, but with lots of pages in the books, the force becomes very noticeable.

What you need

1. 2 litre plastic bottle

2. Blue Tac 3. a bowl of water 4. a ketchup sachet

Marvin says, "Today we are going deep sea diving with this ketchup sachet."

Instructions

1. Put the ketchup sachet into a bowl of water to see if it floats upright - if not then add a little Blue Tac to its bottom.

2. Fill the 2 litre bottle with water right to the top.

3. Push your ketchup diver through the neck of the bottle. 4. Put the lid on tightly, squeeze the bottle hard and watch your diver dive.


The diver sinks when you squeeze the bottle, and rises when you let go.

Tip: if you diver doesn't dive, or sinks without rising, change the amount of blue tac on the sachet.

Squeezing the bottle queezes everything inside it, including the air bubbles in the ketchup sachet. As the air molecules squash together, the sachet gets more dense than the water and itsinks. What happens when you stop squeezing?

What you need

Marvin says, "Hey Milo, let's do some chicken impressions'

1. a plastic cup or yoghurt pot

2. a damp cloth 3. smooth string 4. pencil or biro

Instructions

1. Make a hole in the bottom of a plastic cup with a pencil or biro 2. Cut a length of string, thread it through the hole, and tie a knot in the end inside the cup

to stop it from slipping back through the hole.

3. Take the damp cloth and hold it tightly around the string. Now pull the cloth firmly along the string to hear the cup cluck.


Pulling the cloth along the string makes it vibrate and produce a faint sound. But the cup and air around it also vibrate so the sound is amplified enough for us to hear it.

What you need

1. a paperclip

2. water 3. two identical glasses

Marvin bets Milo that he can make the paperclip move without touching it.

Instructions

1. Put equal amounts of water in both glasses and stand them next to each other but not

touching. 2. Straighten out the paperpclip into a straight wire, then bend it slightly (it should be

shaped more-or-less like a boomerang), Balance it on the rim of one of the glasses.

3. With a wet finger, rub around the rim of the other glass until it "sings" 4. The paperclip moves!


Rubbing the glass makes it vibrate at its natural frequency. Because the other glass is identical it has the same natural frequency and the sound waves from the other glass make it vibrate as well - so the paperclip moves.

What you need

1. two apples with stalks

2. two pieces of string about 30cm long 3. some sticky tape

Instructions

1. Tie a piece of string to the stalk of each apple

2. Use the tape to hang up the two apples so that they are about 6cm apart and free to swing

3. Blow hard between the apples. What happens?


The apples move toward each other. Blowing reduces the air pressure in the gap between the

apples. The air pushing on the outer sides of the apples makes them move into the area of lower pressure, so they move towards each other.

What you need

1. Water

2. Clear plastic watertight bag ( e.g. watertight, resealable food bag) 3. Some pencils

Instructions

1. Fill the plastic bag with water 2. Push a pencil through the bag 3. Then another... and another


The bag doesn't burst because the plastic stretches rather than tears as the pencils are pushed through it. If you take a pencil out you can plug the leak simply by putting it back through the holes.

What you need

1. small plastic drinks bottle

2. some water 3. drawing pin

Instructions

1. Use the drawing pin to make three small holes about 4mm apart at the bottom of the bottle and one near the neck

2. Fill the bottle with water and put the top on (tip: cover up the top hole to stop the water

shooting out of the bottom three). 3. With the top hole uncovered, three water jets will shoot out of the bottom holes. What

happens when you smear the jets together with your thumb, near the holes?


Once the jets have been smeared together they stay together due to surface tension.

What you need

1. a jug of water

2. about 50cm of string 3. A basin or sink

Instructions

1. Tie the string around the handle of the jug and pull it across the top and over the lip 2. Hold the string tight at an angle, below the jug, and begin to pour.


The water flows along the string. The friction betweemn the string and the water slows down the

flow, pulling the water to the string and making it stick to it. Try creating an amazing route for the water by holding the string at different angles, even getting the water to turn corners as it goes down. But be careful, no sharp turns or the water falls off!

What you need

1. Three straws

2. a glass fo drinking water 3. A drawing pin ( for making a small hole in one of the straws)

Instructions

1. Bet your friend that they can't suck up any of the water with two straws in their mouth 2. The catch is that they have to have one straw outside of the glass, and one inside.

What happens? 3. Make a small hole 3 cm from the top of the other straw 4. What happens when your friend tries to suck water using just this straw?


It's impossible to suck water through the straws. In order for the water to be forced into your

mouth, the pressure outside your mouth (atmospheric pressure) needs to be greater than the pressure inside. This means that no matter how you suck, a straw won't work if air can get into your mouth.

What you need

1. a bendy straw

2. water 3. two small flat bowls 4. food colouring

Instructions

1. Fill one bowl with water and a little food colouring

2. Half fill the second bowl 3. submerge the straw in water, making sure you get rid of any air bubbles, and tightly

pinch the ends of the straw before you pull it out.

4. Hold the straw with one end in each bowl, and release the ends when they're under the water


The bowl with the higher water level has more stored (potential) energy, so water moves through the straw to the lower level.

What you need

1. a plastic container

2. a metal frying pan 3. 2 identical ice cubes

Instructions

1. Place the frying pan and the container upside down next to each other. 2. Quickly put an ice cube on each.


Heat can flow through the metal to the ice cube, but the plastic doesn't allow it to flow so freely.

What you need

1. a drinking straw - cut in half

2. a balloon 3. a long piece of string 4. a clothes peg 5. sticky tape

Instructions

1. Blow up the balloon and peg the neck to keep the air in. 2. Thread the straw with the string and then tape it lengthways to the balloon.

3. Tie the string across the room. 4. Now unclip the peg!


As the air rushes out it pushes back on the balloon propelling it forward.

What you need

1. an empty juice carton

2. a piece of string 3. a pair of scissors 4. a washing-up bowl 5. water

Instructions

1. Get an adult to poke a hole in the bottom left-hand corner of each face of the carton. 2. Poke another hole in the top flap and thread the string through it. 3. Put some water in the bowl, stand the carton in it, then fill it up to the top. 4. Lift the carton out by the string.


As the water shoots out it pushes back on the carton with an equal force. Because the holes are off-centre this force makes it spin around.

What you need

1. a glass of water

2. a piece of paper 3. a marker pen

Instructions

1. Draw a column of short arrows. 2. Hold the paper a little way behind the glass and look through the water at the arrows.


The arrows should point in the opposite direction. The water acts like a glass lens, bending the rays of light and reversing the image of the arrows.

What you need

1. a tennis ball

2. a basketball 3. a room without breakables

Instructions

1. Drop the tennis ball from waist height and see how high it bounces. 2. Drop the basketball from the same height and see how high it bounces.

3. Put the tennis ball on top of the basketball and drop them both at arms length from waist height.


The tennis ball should bounce a lot higher than before. When the balls hit the ground, momentum from the basketball was transferred to the tennis ball making it go much higher than before.

What you need

1. a sheet of paper

2. cotton thread 3. scissors

Instructions

1. Cut a thick spiral shape in the piece of paper. 2. Make a hole in the centre and thread the cotton through it. 3. Hang the spiral above the radiator.


The spiral should start to spin slowly. The radiator heats the air around it so the particles have more energy to spread out. This means the air is less dense and rises upwards. The rising air pushes on the paper causing it to spin.

What you need

1. a plastic bottle 2. some hot water

Instructions

1. Very carefully pour a little hot water into the bottle, or ask a grown-up to help 2. Shake the bottle.

3. Pour out the water. 4. Put the lid on, put the bottle down and wait a few minutes.


The hot water gives the air energy - the pressure increases and the molecules spread out (some leave the bottle). When the air cools, the pressure is lower than before because there

are fewer molecules bouncing around. The air pushing on the outside of the bottle has more pressure, which crushes the bottle

What you need

1. a television (turned on!) 2. a rubber band

Instructions

1. Stretch the rubber band between your thumb and first finger. 2. Holding the band between you and the television screen, pluck one side.


You should see the band make zig zag shapes. The television picture is made up of tiny dots flashing on and off. It acts like a strobe light, freezing the band's vibrations at different positions so it looks like it's moving in slow motion.

What you need

1. a piece of foil

2. scissors 3. washing-up liquid 4. a sink or bath

Instructions

1. Take your foil and cut a shape 4cm x 10cm. The shape should look like a house (or rectangle with a triangle on top) with the base of the house being the shortest side. From the base cut a slot with a circle on the top.

2. Gently place your boat into a sink full of clean water. 3. Carefully place a drop of washing-up liquid into the boat's hole.


The boat moves! Water molecules are attracted to each other, creating "surface tension". The soap distrupts the surface behind the boat but the molecules in front are still pulling together, so the boat is pulled forward.

What you need

1. a stick (1m long) 2. a lump of clay

Instructions

1. Push a lump of clay about the size of your fist on to the stick 20cm from the end. 2. With the clay-end closest to your hand, try balancing the stick. 3. Now turn the stick upside down and try balancing it again.


It's much easier to balance it the second way. The stick rotates slower when the clay is at the

top, so there's more time to adjust and keep it balanced. The further the mass is from the centre of rotation (your hand), the slower it rotates.

What you need

1. five wooden toothpicks

2. a small sponge 3. a plate 4. a little water

Instructions

1. Snap the toothpicks in half but don't break them fully. 2. Arrange the toothpicks on the plate so they are spaced out with their broken ends

forming a small circle. 3. Carefully squeeze a drop of water into the middle. Make sure it touches the end of each

toothpick.


The toothpicks move. Just like synchronised swimmers! The water makes the wood expand,

the broken ends press against each other and the toothpick opens out. The same thing happens to doors when it's humid - they swell and get jammed.

What you need

An Alka-Seltzer tablet

An empty film canister

Old newspaper

Water

Instructions

1. Put the tablet in the film canister. Add about 1cm of water.

2. Put the lid on, lightly shake the canister. 3. Quickly place it upside down on the newspaper and stand back!


The Alka-Seltzer fizzes when in water, releasing gas. This gas builds up in the canister until the pressure is too great and the lid is forced off!

What you need

1. a metal coat hanger

2. two pieces of string 3. a fork

Instructions

1. Tie a piece of string to each corner of the coat hanger and wrap the ends around your

fingers. 2. Put your fingers in your ears and ask your friend to tap the hanger with the fork.


It sounds louder because vibrations travel through the metal and string more easily than through air.

What you need

1. a clear plastic bottle

2. a pen 3. a balloon (blow it up a few times beforehand)

Instructions

1. Make a hole in the bottom of the bottle with the pen. 2. Push the balloon inside and stretch it over the mouth.

3. Blow up the balloon. 4. Notice air is coming out of the hole in the bottle. 5. Cover the hole with your finger and stop blowing.


The balloon stays inflated! As the balloon expanded, it pushed air out of the bottle. That made

the pressure inside the bottle lower than the pressure inside the balloon, so it wasn't strong enough to squeeze the air out.

What you need

1. a large glass

2. lemonade (or fizzy water) 3. peanuts (or raisins)

Instructions

1. Fill the glass with lemonade. 2. Stir for 1 min or leave to go slightly flat. 3. Drop some peanuts into the glass.


The nuts float up to the top and fall back down again, like in a lava lamp. Gas bubbles grow on

the peanuts, making them float upwards. When they reach the top the bubbles burst and the peanuts fall back down again.

What you need

1. salt

2. a cup of cold water 3. 20cm of sewing thread 4. an ice cube

Instructions

1. Float the ice cube in the cup of water. 2. Lay one end of the thread (or a loop) on top of the ice cube.

3. Sprinkle a little salt over the top. 4. Wait one minute then gently lift the thread.


Salt lowers the melting point of water so the ice melts. But the water quickly refreezes, trapping the string in place.

What you need

1. a raw egg 2. a hard-boiled egg

Instructions

1. First spin the hard-boiled egg.

2. Stop it and let go immediately. 3. Watch what happens. 4. Now spin the raw egg. 5. Stop it and let it go immediately.


The egg starts spinning! The yolk and the white aren't attached to the shell so they carry on moving when you stop the raw egg. Get a friend to mix up the eggs and use the trick to tell them apart.

What you need

1. a microwave 2. a bar of quality soap

Instructions

1. Put the soap on a dish in the microwave. 2. Heat it on full power for about 1 minute. 3. WARNING: The soap may smell strongly so don't do this before heating food.


Tiny pockets of gas in the soap expand in all directions, pushing the soap into strange and artistic shapes.

What you need

1. a nylon comb 2. a water tap

Instructions

1. Turn on the tap until you have a very thin stream of water.

2. Now grab your comb. 3. Run the comb through your hair several times. 4. Slowly bring the comb towards the water, 10cm below the tap.


1. When the comb is about 3cm away, the water bends towards it!

2. Some objects, like hair and plastic, develop an electrical charge when rubbed together. 3. The charge in your comb attracts tiny electrical charges in the water molecules, pulling

them towards it.

What you need

1. a drinking straw

2. a friend 3. a ruler 4. Scissors

5. sticky tape 6. saucer of water

Instructions

1. The challenge is to lift the water from the saucer using a straw but without sucking. 2. Get your ruler and cut your drinking straw into two pieces: one 3cm long and one 5cm

long. 3. Join the pieces together with sticky tape along one side so they form a 90 degree angle,

but leave both ends open.

4. Stand the smaller end of the straw in the saucer of water. 5. Now blow hard!


When air moves, its pressure falls. So when you blow, the pressure at the top of the straw drops. But the air over the saucer keeps the same pressure, so the water is pushed up the straw.

marvin and milo parte a

Science

balloon close

cups spin

negative charge

water spreads

results explanationas

drops of water

coloured pigments

positive charge