Thursday activities
I hope you are liking the Science experiments I've shared so far this week! Today we are performing some chemical experiments with vinegar. There are lots of different types of vinegar but I'll be using white vinegar. It is made up of about 4% acetic acid and the remaining 96% is made of water. Vinegar is a common food stuff - who doesn't like salt and vinegar chips?! It can also be used to clean your house or put into your washing to help soften your clothes.
Today however, we will be using it to dissolve egg shells, blow up balloons and make a bottle rocket!
Materials needed for today's experiments:
vinegar
eggs
container
bicarbonate soda
balloons
bottle/s - 500mL/600mL works well
bottle - 1.25L
masking tape
3 pencils
thin tissue paper like a serviette
cork
Bouncing eggs...?
Can you make an egg BOUNCE? Not normally!! If you tried to bounce a fresh egg, the shell would break and you would end up with a great big mess! BUT.... if you soak the egg in vinegar for at least 24 hours, the vinegar will dissolve the shell. How? Well, the shell is made of calcium carbonate and the vinegar contains acetic acid. When these come into contact with each other, a chemical reaction occurs! The calcium carbonate is broken down into its parts - calcium and carbonate. The calcium dissolves into the vinegar (and becomes the scum you will see floating in the vinegar) and the carbonate reacts to make carbon dioxide gas - which you can see in the video as the bubbles which form on the egg shell!
But how does the egg actually bounce? Inside the shell is a thin membrane, like skin, which holds the egg white and yolk inside. This membrane will continue to hold the egg together after the shell has dissolved! Amazing! You will be left with the egg white and yolk inside the translucent membrane (it lets light shine through) , and you can even shine a torch through it!
You can then bounce the squishy egg from low heights!!! How amazing!!! Be careful though, if you squeeze too hard or try and bounce it from too high, it will go SPLAT....!
2. Balloon fun
Do you remember what happens when we combine vinegar and bicarbonate soda? We used the chemical reaction to launch a bottle rocket, and to make a volcano erupt!
When mixed, the acidity in the vinegar and the alkalinity of the bicarb soda create a chemical reaction which gives off lots of bubbles and gets all fizzy - this is because the reaction makes carbon dioxide gas. Normally we can't see the gas as it just floats off into the air around us. But in this experiment, we are going to use balloons to trap the gas that is being made - and use it to blow up the balloons!
You just need a bottle, vinegar, roughly two heaped teaspoons of bicarbonate soda and a balloon! Have fun!
3. Bottle rocket time!
Now that you know how to blow up a balloon with bicarbonate soda and vinegar, it is time to make a bottle rocket explode! You may remember doing this in Science Week last year. You need a 1.25L bottle, 3 pencils of the same length, masking tape, a cork, a serviette or thin paper like a square of toilet paper and the bicarb and vinegar.
First, you may need to shave your cork down to fit in the neck of your bottle. It has to be able to be pushed in but fit tightly to stop any of the carbon dioxide gas from the chemical reaction escaping too soon.
Second, tape the three pencils to the side of the bottle to create legs.
Next, pour a cup or two of vinegar into the bottle.
Now you need to make a parcel of bicarbonate soda. using the thin paper, place bicarb in the middle of it and then roll it into a sausage shape so that you can fit it through the neck of the bottle. Make sure you have folded the ends up as you don't want the bicarb to fall into the vinegar before you get a chance to place the cork in!
As soon as the bicarb is in the bottle, quickly push the cork in, turn the bottle over and stand it up then get back and wait for the rocket to launch!