Fun Science

We did a couple of cool science experiments this week.

The first, called Streaky Paper, came from the book "Giant book of cool stuff".


(experiment 13 in the Science section)

You begin by placing bits of chalk into ziplock bags (one colour per bag) and use the rolling pin to crush it up into a fine powder.

Tip each colour into a separate plastic cup and mix with 1 tablespoon of cooking oil.

In a large plastic bowl (as you can see, we used a baking tray instead), fill with water and add 2 tablespoons of white vinegar.

Pour the contents of each cup into the bowl. The chalky coloured oil should form large coloured pools on top of the water.

Lay a sheet of white paper on the surface of the water.

Lift out and place on sheets of newspaper to dry. Once dry, carefully wipe off any surface chalk grains with a paper towel.

We experimented with different amounts of oil - too much left it very pale and light-coloured, too little and the chalk mixture sank to the bottom.

The scientific explanation behind it - the molecules of chalk (calcium carbonate) and vinegar (acetic acid) and water and the surface of the paper all chemically mix together to make a chemical bond. This causes the streaky colours to stick to the paper.

Suggestions for use - wrapping paper, writing paper etc.

Our other experiment came from reading 'The Magic School Bus gets baked in a cake: A book about Kitchen chemistry'.



It's a simple one but it amused us for a while :)

Put some water in a jug and add 2 teaspoons of bicarb soda (baking soda) and 3 teaspoons of vinegar.

Throw in 5 or 6 peanuts and watch what happens!

The bubbles from the carbon dioxide will form on the surface of the peanuts and cause them to float to the top. The bubbles will then slowly pop and the nut will fall back down again. Repeat :)

We used cashews because that's all we had - they were probably a bit large as they were quite slow to rise - it did eventually happen though. We also added some sultanas later on and they were much quicker to rise and fall.

So there you go, some simple but fun science for the week!