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.