Store cupboard science – another helping!

We’ve been back in the store cupboards and finding things we can use to have some fun with food science. Tilly and Morgan helped out again and had a great time proving that learning at home is never boring.

The sisters are usually at primary school and these ideas are designed to help keep their science learning super sharp and up to date.

 

Inflate a balloon without blowing air into it

 

 Lots of us have some yeast left over from the frenzy of lockdown baking – put it together with a balloon and some water and magic happens.

Add two teaspoons of dried yeast and two teaspoons of sugar to half a glass of warm water.

Stir well and pour the mixture into a bottle. Glass is best but you need a bottle with a rigid neck.

Stretch a balloon over the top of the bottle and leave in a warm place.

Watch what happens…..

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What’s happening here?

Yeast is a fungus which converts the sugar into  carbon dioxide gas – which are the bubbles you see forming.  The gas bubbles expand to fill up the bottle and then start to inflate the balloon. The dried yeast needs warmth and moisture to become active and start growing.

 

Watch Plants & Vegetables Drinking

 

For this experiment you’ll need a flower (a white carnation or similar light coloured flower is best), a stick of celery, food colouring and water.

Trim the end of the flower’s stem.

Take the stick of celery and cut the end.

Pour water into a glass and add in around a teaspoon of food colouring.                             

Leave the flower and celery for a day in the water and see what happens.

 

What can you see?

The flower petals should have changed colour. You’ll also see tiny dots in the end of the celery – that’s the food colouring too.

Plant stems have narrow tubes (xylem) inside them that draw up the dyed water into the petals. It’s called transport and this is how plants drink water and take in minerals from their roots.

 

 

 

Make your chocolate last longer!

 

 

So, who doesn’t have a bit of chocolate in their house at the moment? Not many of us. But how do we make those final squares last the longest?

Which chocolate melts the fastest? Dark or milk?

Can you guess which one…..

 

 

For this experiment you’ll just need two types of chocolate – dark and milk – and a stopwatch. Have a couple of squares at the ready – this might take a few attempts 😊

Place a square of milk chocolate in your mouth and suck it – no chewing!

Time how long it takes to melt.

Now place a square of dark chocolate in your mouth and suck it – don’t chew!

Time how long it takes to melt.

Which chocolate melts in the fastest time? And how does it taste?

So, were you right? Which one melted the fastest? If you guessed correctly award yourself another piece of chocolate 😊

 What happened here….

 Milk chocolate has more fast-melting fat molecules in it than dark chocolate. The dark chocolate contains more cocoa power which makes it melt more slowly in your mouth.

Also, because you can’t taste chocolate until it melts you should be able to taste the milk chocolate square quicker than then the dark chocolate square.

 

Getting the DNA out of strawberries

 

Every living thing contains nucleic acid – either DNA or RNA. It contains genetic instructions for how organisms are made and work. From the colour of the strawberry to its size and flavour – all that information is contained in its DNA and has been passed down from the plants its been grown on from.

 

Amazing fact!  Every human cell – except mature red blood cells (erythrocytes) – contains two metres of supercoiled DNA?

But how can we see DNA? This experiment tells you how.

 

Warning! Though this experiment will produce an attractive looking liquid please don’t be tempted to drink it.

You’ll need a plastic bottle, surgical spirit, a sealable  sandwich bag, a glass,  half a glass full of strawberries, washing up liquid and water.

Place a plastic bottle of surgical spirit in the freezer for an hour.

Put some strawberries and a tablespoon of water into a reseable sandwich bag.

Close the bag and squish the berries.

Open the bag and pour the juice into the glass.

Add a tiny drop of washing up liquid.

Tilt the glass slightly and slowly pour in icy-cold surgical spirit until the glass is half full.

What do you see? Leave for half an hour and come back.

 

 

 

Do not drink this mixture!

 

Now for the science

 

Squishing the berries breaks them up and allows you to collect cells, the washing up liquid breaks down the cell membranes and releases their DNA. The cold surgical spirit separates the DNA so it clumps to form sticky cloudy strings.