Store cupboard science – milk, eggs and a minty geyser!

We just can’t stop exploring food science with our fun experiments. And they’re getting really exciting! Tilly and Morgan have been experimenting with liquids – with some amazing results. As always these suggestions will need to be supervised by adults, but don’t worry- we promise you’ll be fascinated too.

 

Making Butter from Milk

 

There’s nothing like some butter on our bread. Lots of people are baking but how about making something to put on it?

All you need is some double or whipping cream and a clean jam jar. You also need a bit of stamina!

Half fill the jam jar with the cream and pub on the lid.

Shake the jar for about five minutes (this is test of stamina – five minutes can feel like a long time).

Keep shaking until you see a yellow blob of butter floating in some liquid.

Take the butter from the jar and drain from the liquid – spread on some bread. Yum!

 

 

Why?

Cream contains lots of fat molecules.  When you shake the cream, the fat starts to clump together to form butter which is solid. The liquid left behind is called buttermilk and has very little fat in it.

 

Making Plastic from Milk

 

Milk is really versatile, you can make lots of things using this – but this one is definitely not for eating.

You’ll need a cup of milk, vinegar, a saucepan and sieve and an ice cube mould.

If you’ve got a shaped mould, such as a heart or star, then you’re going to make a more interesting plastic shape. 

Gently warm the milk until it’s warm but not boiling.

Turn off the heat, add two tablespoons of vinegar and stir until lumps form.

Pour the milk into a fine sieve.

Collect the lumps and press into different shapes using the ice cube mould.

Now you have to wait – leave to dry for 2 days and then paint – but remember don’t eat them!

The science bit…

Milk contains a protein called casein, which is a very long molecule. When vinegar is added to milk it makes the casein molecules clump into rubbery bendy lumps that then harden as they dry. Casein can also be turned into hard plastic to make buttons!

 

Rubber Egg

 

This experiment needs a bit more patience – but it will be worth it, we promise.

You’ll need a raw egg (still in its shell), vinegar, water and a clean jam jar.

Put the egg in the jar and pour in enough vinegar to cover it.

Leave it for a day. 

Change the vinegar on the second day and leave for a week.

Remove the egg and rinse in cold water.  How does the egg look and feel? Play with it. You can bounce it – but not too hard or it will explode.

What’s happened?

The acetic acid in the vinegar reacts with the calcium carbonate in the eggshell. It makes the shell dissolve but leaves the membrane inside the shell unchanged.

This membrane gives the egg its rubbery consistency, as the egg is uncooked the white remains more or less transparent.

 

Minty Geyser

 

 You don’t have to go to Iceland to see a geyser! They can be created in any open space with this fun experiment.

It needs just three things: a plastic bottle of diet cola (diet is best – less sticky!), some cardboard and a packet of Mentos mints.

Take the bottle of cola and place upright outdoors – with plenty of space all around.

Roll a cardboard tube to fit into the neck of the bottle.

Take the packet of Mentos and remove from their packet – line them up in the cardboard tube – keeping your finger over the hole to prevent them from falling out.

Place  the end of the tube over the top of the bottle, remove your finger, allowing all the mints to fall into the bottle – RUN FOR COVER!

The diet cola shoots high into the air and rains down!

 

Why?

This about carbon dioxide again – when the mints are dropped into the cola, their pitted surface collects lots of carbon dioxide molecules.

As they sink to the bottom of the bottle the carbon dioxide is released all at one and goes rushing upwards towards the spout of the bottle. This reaction is of many that is used in the food industry – it’s how beer is dispensed by pumps in pubs

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