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36<br />
Do try this<br />
at home…<br />
A homemade lava lamp<br />
This lava lamp is short-lived, but<br />
pretty magical.<br />
You’ll need:<br />
• A glass<br />
• Vegetable oil<br />
• Water<br />
• A bright food colouring (e.g. red or<br />
green)<br />
• An Alka-Seltzer tablet<br />
What to do:<br />
• Fill the glass to about halfway with<br />
vegetable oil.<br />
• Add around a fifth of a glass of<br />
water.<br />
• Add around 10 drops of food<br />
colouring.<br />
• Drop in the Alka-Seltzer tablet and<br />
watch the marvel unfold.<br />
Why it works:<br />
The oil floats on the water. When<br />
you drop the tablet in, it reacts with<br />
the water to make carbon dioxide<br />
bubbles. They carry the coloured<br />
water to the top, before popping<br />
and sinking back down.<br />
Iceberg<br />
For this experiment, you probably<br />
have everything you need already.<br />
You’ll need:<br />
• A glass<br />
• Ice cubes<br />
• Salt<br />
• String<br />
What to do<br />
• Dangle a piece of string in the<br />
glass with one hand.<br />
• Pop ice cubes into the glass so that<br />
it’s at least half-full.<br />
• Can you pull the ice-cubes out of<br />
the glass using the string?<br />
• Repeat the first two steps.<br />
• Pour a couple of tablespoons of<br />
salt over the ice cubes and the<br />
string.<br />
• Wait 10 seconds and pull the string<br />
out.<br />
• This time, the ice cubes should<br />
come out with the string.<br />
Why it works<br />
The salt makes the edges of the ice<br />
cubes start to melt but then they<br />
partially refreeze, sticking to the<br />
string as they do.<br />
Runaway milk<br />
Fun science experiments that the whole family will enjoy<br />
Don’t worry, this is a lot less messy<br />
than it sounds.<br />
You’ll need:<br />
• A plate or wide, shallow bowl<br />
• Full fat milk<br />
• Food colouring (ideally three<br />
different colours)<br />
• Washing-up liquid<br />
What to do<br />
• Pour some milk into the plate.<br />
(You only need it to be around a<br />
centimetre deep.)<br />
• Add a few drops of food colouring<br />
in different areas. Not too many,<br />
there should be large gaps<br />
between each one.<br />
• Dip a finger in the washing-up<br />
liquid and then touch one of the<br />
spots of food colouring.<br />
• Repeat with other spots of food<br />
colouring.<br />
• The colour will swirl away from<br />
your touch.<br />
Why it works<br />
The milk and washing-up liquid<br />
can’t mix. What you’re seeing is the<br />
fat particles swirling away from the<br />
washing-up liquid. Don’t have food<br />
colouring? Try touching a felt tip<br />
pen to the milk instead.
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