Investigation 1: Monday

Walking on water.

The surface of water is like a thin, stretchy skin, held together by a force called surface tension. Light objects can balance on this skin – as long as the don’t break it.

Try this simple experiment.

Float a needle!

You will need:

• A needle
• A bowl of water
• A piece of tissue

Instructions:

1. Drop a needle into a bowl of water and watch it fall to the bottom.
2. Remove the needle and dry it.
3. Place the needle on a piece of tissue and lay it carefully on the water.

What happens?

The tissue sinks, leaving the needle on the water’s surface. The needle is light enough to balance on the water’s skin, as long as it doesn’t pierce it.

Repeat with the tissue paper again but this time add a few drops of washing up liquid!

What do you think will happen?

Can you explain why?

Investigation 2: Tuesday

The nail varnish test!

The surface of water holds together like a skin because of surface tension.

The needle demonstrated how water has a skin.

Nail varnish is light enough to sit on the water’s surface. Let’s see what happens when you add drops of different colours of nail varnish to a small bowl of water.

You will need:

• A bowl of water
• Different colours of nail varnish (approx. 3)
• Sheets of thick white paper

Instructions:

1. Very gently drag a cocktail stick through the nail varnish to make a pattern.
2. Lay some paper over the top, then lift it off.

When you lay the paper over the pattern, the varnish pattern sticks to the paper instead.

Try making lots of different patterns!

Investigation 3: Wednesday

Water resistance!

Wax and watery paint.

This investigation shows us why water stays on some surfaces, but runs off others – an effect known as water resistance.

You will need:

• Wax crayons
• Margarine
• Soap
• Thick white paper
• Watery paint
• Paint brush

Instructions:

1. Use a wax crayon to draw some shapes on thick white paper.
2. Brush thin, watery paint over the top.

What happens?

The watery paint runs off the crayon because wax is water resistant. Paint sticks to the paper because paper is absorbent.

Repeat this experiment using margarine.

What happens?

Can you explain it?

Repeat this experiment using soap.

Use a piece of soap to draw a shape on some paper, then paint over it.

What do you notice this time?

Although soap is made from oils and fatty products, it also has ingredients in it which help it mix and foam up in water.

The soap does not resist the water paint!

Investigation 4: Thursday

Dye, oil and water!

Find out how some substances mix and others don’t, and discover the amazing effects you can create by adding food dye to oil and water.

Make dye drops!

You will need:

A tall glass

Vegetable oil

Food dye/colouring

Instructions:

1.Pour some vegetable oil into a tall glass.

1. Add a few drops of food dye.
2. Watch what happens.
3. Push the drops of dye gently down into the oil with a spoon.
4. Watch what happens.

Each dye drop forms a tight bead shape because dye does not mix with oil, so the drop can’t spread out.

The dye drops sink in the oil because food dye is denser than oil. Everything is made of tiny particles. Density is about how heavy and how spread out the particles in a substance are. If two liquids of different densities are mixed, the less dense one floats on the denser one, eg. oil floats on water.

Make exploding dye drops!

Fill a tall glass with water, add some vegetable oil and let it settle. Then, add a few drops of food dye and watch what happens! (Nudge the the drops with  aspoon to make them sink more quickly.)

Can you explain what is happening and why?

Investigation 5: Friday

Making bubbles!

Make your own bubble mix and use it to learn how bubbles are formed.

You will need:

• Half cup of washing up liquid
• Two cups of water
• Food dye (optional)
• Two teaspoons of sugar
• An empty plastic water bottle
• An old sock

Instructions:

1. Gently mix half a cup of washing up liquid, two cups of water and two teaspoons of sugar in a jug.
2. Carefully cut the end off a plastic bottle.
3. Dip the cut end in a tray of bubble mix. Then take it out again.
4. Blow through the neck of the bottle to make a bubble.

The bubble mix forms a stretchy ‘skin’ over the object. When you wave or blow air into it, the skin stretches and traps some air inside it, making a bubble.

No matter what shape your wand is, bubbles are always round.

Now make colourful sock bubbles!

Repeat the above but this time place an old sock (clean!) over the cut end of the plastic bottle.

1. Add some food dye to bubble mix in a bowl.
2. Dip the sock covered end in the mix.
3. Hold the sock covered end over a piece of paper.
4. Blow through the neck of the bottle. Watch what happens!

As you blow, the bubble mix passes through lots of tiny holes in the sock, making small colourful bubbles that cling together. As the bubbles burst, they leave bubble shaped patterns of dye on the paper!

Have fun with it!