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Fun!

Floating Ice

Get some cotton and an ice-cube. Lay the cotton on top of the ice-cube, making sure you have two long ends on either side of it. Take a pinch of salt and sprinkle it over the ice-cube. Wait for one minute.

Take the thread at either end and gently lift!

Explanation

Putting the salt onto the ice-cube makes the ice-cube melt. The ice then re-freezes itself over the cotton - meaning you can pick it up.

 

Tiny Tornado

Get two plastic 2 litre soft drink bottles. Fill one half full of water and add food colouring. Place a plastic washer (ask your parent) on top of the bottle. Put the other bottle upside down,neck to neck with the other bottle. Wrap lots of masking tape around the necks to make sure they're very tightly attached.

Turn the bottles over so the one with water in is on top and lightly shake them in a circle - then put them down and watch.

Explanation

This water based version of a tornado is called a Vortex. Tornadoes are formed below strong thunderstorms, when warm, humid air tries to push through cool, dry air. Pushed by a cross wind the air begins to swirl and forms a "funnel cloud". If this touches the ground it is called a tornado. Most tornadoes stay on the ground for between 10 and 15 minutes.

 

The Cornflour Experiment

Empty a 500g box of cornflour into a large bowl or deep mixing tray, then add water, a little at a time, until you get a consistency like melted ice cream. Make sure that it is well mixed or you will get a surface of water on the top, which means it won’t work!

Now try the following things:
  1. Punch the mixture. You’ll notice it’s really hard, and it may even crack
  2. Slowly push a finger into the mixture and it will slide in as though it’s a liquid.

Explanation

Most fluids get thinner as you move them around, like ketchup and emulsion paint. The cornflour mixture does the opposite. When you stir the material slowly it flows like a thick liquid, but if you try and punch it, it seizes up and becomes quite solid. This is because when you mix the cornflour with water, you create a mixture of starch molecules suspended in water.

When the mixture is stirred, the molecules flow amongst the water, but if you ‘hit’ them, the water is forced out of the gaps between them and so the mixture appears to turn solid.

Can you come up with other examples of both types of fluids or corresponding effects? For example, something similar happens when you walk on wet sand: if you run it seems quite solid, but if you stand still you sink in.

 

Make a Thermometer

Get a water/juice bottle with a screw top. Take the top off and fill with water and add a few drops of food colouring (or cordial!). Make a hole in the middle of the top (an adult will probably have to do this for you) and screw the top back on.

Take a straw and put in through the hole, then take some plasticine (or blu tac) and squish it round the straw and the hole. Put some white card behind the straw (where it sticks out). Put some marks on the paper first if you like, and then put the bottle in hot and cold places and see the temperature change!

Explanation

When the water in the bottle gets hotter the water in the straw gets higher. This is because of its 'molecules'. There are spaces between all molecules. When the water gets hot, the space between the molecules get bigger so the molecules spread out and make the water expand.

 

Building a Paper Bridge

First get two blocks that are the same size. Then using a piece of paper, try to make a bridge and make it as strong as possible. Try the weight of the bridge by putting coins on it.

Can you make the strongest bridge without looking down to see the answer?

Explanation

The strongest bridge is made by folding the paper like a fan, into a row of triangles. Weight provides two kinds of force: 'compression' and 'tension'. Compression pushes down on the structure and tension pulls and stretches the structure. Compression pushes down equally on two sides of the triangle, causing the base to be pulled equally in two directions, which creates tension. The triangle is the strongest structure because all three sides bear the load. In a square, only two sides of the four bear the load. This equaling of the forces makes the triangle the strongest structure.

 

For more experiments, why not visit some of the websites we've listed in our fun website section!
Download list of Fun Websites

Fascinating Facts!

See below for some amazing facts - great to impress people with!

  • Lightening bolts generate temperatures five times hotter than the 6000oC heat of the sun's surface!
  • The poison-arrow frog has enough poison to kill about 2,200 people!
  • Camels have three eyelids – to protect their eyes from sand in the desert
  • The fastest computer in the world (the IBM ASCI white supercomputer), weighs as much as 17 elephants
  • 75 percent of your brain is made of water
  • The only man-made structure visible from earth is the Great Wall of China
  • Mint contains menthol which (temporarily) deadens the hot receptors in your mouth
  • You are born with 300 bones, but when you reach adulthood you only have 206
  • Concorde grows 30cm during a flight between the UK and the USA
  • The Earth weighs around 6,588,000,000,000,000,000,000,000, tons
  • Neutron stars can spin up to 1000 times a second but your music CDs spin at just 10 times a second
  • Chocolate is the world’s most chemically complex food
  • You can't catch a cold at the North Pole in winter
  • Dolphins sleep with one eye open!
  • There are about 10,000 taste buds on the surface of your tongue
  • Your heart beats over 100,000 times a day
  • There is no wind on the moon, so (unless disturbed) an astronaut’s footprints will last forever
  • Men are six times more likely to be struck by lightening than women
  • A hummingbird weighs less than a penny
  • If less than 0.1 percent of the sea’s renewable energy was turned into electricity it would supply the worlds demand for power five times over
  • The tongue of a blue whale is the size of an elephant!
  • If all the body's nerves could be laid end to end they would measure 47 miles
  • 121 tortillas would produce enough energy to power a space shuttle for one hour
  • Slugs have four noses
  • There are more stars in the universe than grains of sand on the earth!
  • A giraffe has the same number of bones in its neck as a human
  • No-one has ever discovered two snowflakes with the same pattern
  • A crocodile can grow new teeth to replace old ones
  • The electric chair was invented by Alfred Southwick - a dentist!
  • A left handed person finds it easier to open a jar than a right handed person because they can supply a stronger anticlockwise turning force
  • There are more than 50,000 earthquakes every year across the world
  • Some trees bear oranges for over 100 years
  • Sleeping uses up 60 Calories
  • Ants have two stomachs - one for their own consumption and one to carry food to be shared with other ants
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