Imaginative Teaching Resources & Inspirational Career Ideas from the Chilled Food Industry
Although we’re might still be in holiday mode there’s always a lot of fun to be had with science. As these experiments, demonstrated by Tilly, prove!
Fluffy Egg White
This experiment will have a tasty result – we promise.
You’ll need an egg (Lion Mark for extra safety) and an electric mixer, plus some sugar.
Separate the egg yolk and white either using the egg shell or allow the egg white to slip through your fingers after cracking onto your hand. Wash your hands after this.
Beat the egg whites with an electric mixer until they start to go fluffy – keep beating until you make the egg white stand into peaks.
Why? 
Egg white contains lots of protein, whisking creates air bubbles and changes the protein so it surrounds the air bubbles making the egg white expand into a stiff foam.
And finally – the tasty bit. Add 50g of sugar and bake in a pre-heated oven (150C gas 2) for 20-30 mins, turn the oven off and leave to go cold to turn these into meringues!
Apples Changing Colour
All that you need for this is an apple, lemon juice, water and small bowls or plates.
Cut the apple into quarters and place into small bowls or plates.
On one apple slice cover with water, another with lemon juice, another with tap water and label. Leave one without anything on it.
Check every 15 minutes to see what happens.
What else could you sprinkle or cover the apple slices with?
What’s happening?
When apples are cut, the exposed fruit underneath the skin reacts with oxygen in the air, which causes the apple slices to turn brown. Lemon juice is acidic (and why it tastes so sour!) and will react with oxygen before oxygen reacts with the apple. A light spritz of lemon juice will keep your apples fresh without altering their taste too much. Would you like to eat the apple slice with vinegar?!
Invisible Ink
Do you need to write a secret message but just don’t have any invisible ink?? Don’t worry we can help – lemon juice will do the job
Squeeze the juice from a lemon, dip a brush in the juice and paint a pattern on white paper. Let it dry – can you see your message?
Grab a hairdryer and gently warm the paper (or get an adult to place in the oven for 10 mins at 150°C).
What happens?
When the lemon juice dries it looks invisible but when its heated in the oven, the juice reacts with the oxygen in the air and turns brown, showing clearly your message. Lemon juice reacts naturally with air over time to go brown but heating speeds up this process.
Getting a Reaction
With Tilly’s help you’re about to discover why we use bicarbonate of soda in baking…..
This simple experiment needs water, a heatproof bowl, bicarbonate of soda and a helpful adult.
Ask your adult to pour some water that has just boiled into a heatproof bowl. Stir in a heaped teaspoon of bicarbonate of soda – What happens?
Now pour some cold water into a bowl and add a heaped teaspoon of bicarbonate of soda and watch what happens?
Why?
Bicarbonate of soda fizzes gently when it mixes with hot water because the heat starts a change that creates carbon dioxide gas – which is why baking powder which contains bicarbonate of soda is used to make cakes. The oven’s heat makes the wet bicarbonate of soda produce carbon dioxide gas which bubbles up inside the cake and tries to escape making the mixture rise. Cold water has no effect.