What happens:

Once 36-48 hours have passed, carefully remove the egg from the jar and you will see that the shell has disappeared and your are left with a delicate but intact egg!

An egg shell is made up of calcium carbonate which is an alkaline, while the vinegar is an acid. Acid reacts with alkaline to produce salt and carbon dioxide.

As soon as you cover the egg with the vinegar you will notice little bubbles of carbon dioxide forming. During the time the egg is in the jar, the shell dissolves leaving you with a delicate see through membrane keeping the egg intact.

If you shine a light near the egg you should be able to see the light through it.

For this project you will need:

• Clear jar with a lid
• Adhesive tape
• Scissors
• Sheet of white paper
• 3 x 3volt coin-shaped batteries
• 3 x small LED light bulbs with prongs or a string of LED lights

How to make your Hex Allen nightlight:

1. Place the prongs of one LED bulb on either side of a battery. Make sure the longer prong is in contact with the plus side
2. Hold the prongs tightly against the battery and it should light up
3. Tape the prongs in place so the light stays on and repeat for the other bulbs/batteries
4. Tape your battery/bulb combos inside your jar. You could tape one to the underside of the lid and one on the bottom of the jar and one along the side
5. Place your paper around the jar and cut a piece to size so that it completely covers the clear surface of the jar
6. Tape it in place
7. Turn off the lights and you will have a night light ready to use.

What Happens:

The white paper spreads the light and makes it stand out better. You can also draw a design on your paper or experiment with different types of materials to see which one best spreads the light.

How to make a CD hovercraft:

1. Make a small cone shape with the card. The biro lid should be flush with the top of the cone when placed inside, and the bottom of the cone should be slightly larger than the hole in the centre of the CD.
2. Without covering the hole in the biro lid, affix it to the top of the cone using adhesive tape.
3. Place the CD shiny side up on the table.
4. Place your cone construction over the centre of the CD and form an airtight seal between the bottom of the cone and the hole in the centre of the CD using adhesive tape.
5. Fix the balloon over the top of the cone and hold it in place
6. Move your CD around on a hard, flat surface and watch as the movement inflates the balloon!

How to create your erupting volcano:

1. Take the materials outside as this is going to be messy!
2. Place the bottle in the centre of the tray
3. If you are making your volcano, mix all the ingredients together and mould the dough around the bottle leaving the mouth of the bottle open
4. Add the baking soda to the bottle
5. Pour in some food colouring
6. Carefully but quickly pour the vinegar into the bottle
7. Stand back and watch your volcano erupt!

A quick alternative to this method is to use a packet of Mentos and a bottle of fizzy drink. Remove the lid from the drink and drop in a full packet of Mentos. Stand back and watch it erupt! This is also best done outside.

What happens:

When acids and bases come together they go crazy! Acid+Base = Salt + CO2. So in the first example the vinegar (acid) reacts vigorously with the baking soda (base) and causes the eruption.

How to filter your dirty water:

1. Make your dirty water
2. Cut the top half off the bottle
3. Invert the top half of the bottle so the mouth faces downwards
4. Sit your inverted bottle top, mouth facing downwards, into the bottom of the bottle leaving the mouth of the inverted section hanging a few inches above the bottom of the bottle, so your water can filter in without covering the mouth of the bottle.
5. Layer in your filter materials to the inverted section starting with the coffee filter paper, next add the kitchen towel, next the cotton wool, followed by the charcoal, fine sand and the top layer should be gravel.
6. Pour the dirty water into the filter you have just made and watch it come out clean in the bottom of the bottle

What happens:

The particles of dirt become trapped in the filter layers and only clean water filters though. This is how underground water gets purified. Chemical engineers use this method as one of the stages of water treatment in a water treatment plant.

Can a can balance at an angle? The answer is yes, so long as it it weighted at the bottom!

What you will need for this experiment:

• An empty aluminium drinks can
• Some water
• A tray (in case of spills!)

How to balance your can:

1. Try to tilt your can when it is empty – frustrating as it just falls over
2. Add a little water to the can so that it just covers the bottom
3. Place the can on a tray and try to tilt it again
4. This time it should balance at an angle and hold

What happens:

By filling a small amount of water into the can you change the centre of gravity. Now when you tilt the can the water acts as a weight and helps it to balance perfectly when it comes into contact with the surface of the tray.