Store cupboard science – festering bread, sugar and exploding bags!

For this set of store cupboard science experiments we’ll be going outside again for some spectacular results!  We’ll also be refreshing our handwashing skills and creating sweet treats.

Morgan and Tilly helped us with these and were supervised at all times. Please be careful and, like us, enjoy these experiments with your young ones.

Hand Washing Experiment

 

Hand washing has been on all our minds for months now. We should all know the correct way (for a reminder take a look at our handy poster!) but try this experiment and you’ll see just how important it is to getting rid of the microbes we carry on our hands. Prepare to be surprised!

You will need some slices of bread (we used white bread, you’ll see why later) four resealable plastic bags with labels, a pair of tongs and a pair of dirty hands.

Use the tongs to put a  slice in the resealable plastic bag – and label ‘no touch’ (or ‘control’)

Handle another with dirty hands and really press your hand into it.  Put this into another resealable bag and label – ‘dirty hands’.

Wash your hands (follow the guidelines on our poster) but don’t dry them and handle a slice. Put that into a bag and label ‘clean wet hands’.

Wash your hands again and dry them well – put that slice of bread into a bag and label – ‘clean dry’.

Place the bags in a cool dry place and look at every day (but don’t open the bags!)

Which one gets mouldy first? Which one has the most mould?

 

Shocking isn’t it? Why the mould?

When we have been out in the garden playing it can be easy to see the dirt on your hands, but what you can’t see are the invisible to your eye microbes which can accumulate on your hands throughout the day.  You also need to dry your hands thoroughly after washing as microbes spread more easily on wet hands than dry hands.

 

Sugar Crystals

 

 This sweet and simple experiment needs 120ml of just boiled water, 130g of sugar, food colouring, a jam jar and wooden skewer.

Pour the water into a jug, add the sugar and stir until it dissolves.

Add a couple of drops of food colouring and mix well.

Pour the mixture into a clean jam jar. Dip a wooden skewer into the warm mixture, take out and sprinkle the wet end with sugar.

Leave to dry.

Once the mixture in the jar is cool, attach a clothes peg to the clean end of the skewer and balance on the top of the jar – the sugary end is in the mixture.  Leave the jar in a warm place and after a few days the skewer should be covered in sugar crystals. Eat like a lollipop!

 

The science behind this magic…..

When the water is hot it absorbs more sugar than it could absorb at room temperatures, creating a super saturated solution.  As it cools the water is unable to hold as much sugar and the sugar solidifies again.  The tiny sugar crystals cling to any available surface – such as your stick, and then each other.

 

Whipped Cream     

 

A lovely sponge filled with cream is a great treat but what makes that cream so thick?

For this one you just need a small pot of double cream, a bowl and electric whisk, or if you’re feeling strong a hand whisk.

Whisk the cream in the bowl with a hand whisk or electric beater.  Whisk until you can make it stand in soft peaks – look at how the cream has changed.

Why?

After whisking the cream becomes thicker and appears more like a solid. Whisking the cream creates air bubbles which become trapped by the fat in the cream.  This makes the cream thick and foamy and fills more space in the bowl. We ate ours with waffles and strawberries!

Exploding Bags!

 

Let’s go outside for this one

 For this you’ll need bicarbonate of soda, toilet paper, vinegar, water and a medium size sealable bag.

Place a tablespoon of bicarbonate of soda  on 2 sheets of toilet paper and twist into a packet.

Pour half a cup of vinegar into water into the bag.

Seal up the bag leaving just enough room to squeeze in the packet of bicarbonate of soda in the gap, squeeze the bag and hold the packet through the bag so it doesn’t  drop into the liquid. Seal the bag fully.

Give the bag a quick shake so the toilet paper gets wet.

Drop and retreat!!! Watch the bag expand and then POP!

 

Why the dramatic reaction?

This is carbon dioxide being produced, similar to our store cupboard science yeast experiment.  In that one the gas was able to escape or released into a balloon.  This time we have trapped it, so when the reaction between the sodium bicarbonate (bicarbonate of soda) and the acetic acid takes place, the gas is created and fills the bag until there is no more space inside.