If you haven't seen this before, it's a really simple thing to set up.
I had vinegar in the bottom of the bottle and bicarbonate of soda in the balloon.
When you mix them by tipping it in, they react
to form carbon dioxide and that's what's inflated the balloon.
It's a really fun way to blow up a balloon,
but we can use this very simple reaction to do a slightly longer activity that
gets the children really thinking about science.
This is an activity that I call 'fizzy cubes'. I've just got an
ice cube tray and I've put bicarbonate of soda in half the tray,
roughly similar amount in each cube, and in the other half
I've put in edible ingredients from around kitchen. I've got soy sauce,
honey, lime juice and apple juice, orange juice, and vinegar.
Now the activity itself is really simple we're just gonna spoon the
bicarbonate of soda
into into each ingredient and look really closely at what happens.
What's it doing?
Fizzing up!
What's coming out? Bubbles!
This activity is all about observing what happens when you mix two things
together,
so it's a good idea to ask questions to make sure children notice the different
behaviours
when the bicarbonate of soda is added to the different ingredients.
Is that one fizzing more or less than the soy sauce?
More. Woah it's nearly coming out!
The fizzing is a result of a chemical reaction.
In simple terms this is when two things come together
to make something new. It's useful to point out that the new thing being
produced in this reaction is a gas,
carbon dioxide, which is what makes the fizz, or tiny bubbles.
Is it still doing it? As you add more is it still fizzing up?
The amount of fizzing depends on how acidic the other ingredient is.
The bicarbonate of soda doesn't react with ingredients that are not acidic.
You can use this activity to get into the balloon inflation by asking
whether making gas like this could be useful, and then suggest inflating
a balloon using the best reaction.
It's not generally a good idea to eat your science experiments.
But it's yummy!
Put some powder in and then some vinegar,
and we mix them in the bottle, and put the baloon on top.
I found that blowing up the balloon once before the experiment
to pre-stretch it really helps, as does making a paper funnel
to get the powder into the balloon. Okay how many spoons shall we put in?
Four. Why four?
If you've got time, and don't mind the mess, you can investigate howmuch of the ingredients
are needed to blow up the balloon well.
I use about 8 teaspoons of bicarbonate,
and fill the bottle about a third of the way up with vinegar to make sure the
balloon inflates properly.
Perfect, that's it.
What's it filled with now? Air.
Do you think it's the same as the air that we breathe?
No. Why not?
Because it's made out of this, and air that we breathe isn't made out of this.
Ah, very good!
Now I know that we've looked at chemical reactions,
Viola's a bit too young for that but it doesn't really matter.
What we both got out of it is is that we were
looking closely at what happened during the reactions, and had a good time doing it.