Chemical reactions to try at home

Experiment alongside Ellie from the Crick's education team to create your own chemical reaction and make an invisible fire extinguisher as part of our Family Zone.

Create your own chemical reaction

Make sure that you have adult supervision for these experiments!

Create your own chemical reaction

What you'll need

  • Bicarbonate of soda
  • A powder that looks similar to bicarbonate of soda e.g. flour or icing sugar
  • Vinegar
  • A plastic drinks bottle (approx. 500ml)
  • A balloon or plastic bag
  • A hair tie (if you're using the plastic bag)
  • Spoon

Step 1 Pour vinegar into the plastic drinks bottle until it is around 2-3cm full.

Step 2 Make a funnel with a piece of paper and use it to put two spoons of bicarbonate of soda into the balloon/ plastic bag.

Step 3 Fasten the neck of the balloon around the rim of the drinks bottle, or the plastic bag using the hair tie, careful to not let any of the powder fall into the vinegar yet.

Step 4 Upend the balloon/plastic bag quickly to let all of the powder fall into the vinegar, whilst keeping it sealed around the rim of the bottle.

Step 5 Watch the balloon start to inflate!

Step 6 Try this experiment again with another powder which look similar to bicarbonate of soda e.g. flour or icing sugar. Does the balloon still inflate?

The science

Experiments at the Crick's public family fun day.
  • Chemical reactions happen when chemicals, (e.g. the acid ‘vinegar’ and the base ‘sodium bicarbonate’) are changed into something new, in this case, a gas – carbon dioxide, which blows up the balloon.
     
  • When you substitute the sodium bicarbonate with something that looks similar, icing sugar, the reaction doesn’t work anymore because the icing sugar doesn’t have the same chemical properties as the sodium bicarbonate.

Real life science at the Crick

Acids can also be found in living things. For example, chemical reactions involving amino acids are needed for growth, including of the bacteria that cause disease.

Scientists at the Crick are investigating how the bacterium that causes the disease tuberculosis (TB) can be killed by antibiotics. Scientists have found that tuberculosis can be treated by giving people a drug that looks a lot like the amino acid the bacteria need to grow.

But just like in our experiment, even though it looks similar, this time the chemical reaction doesn’t work so the bacteria can’t grow properly. By understanding this process, scientists can design better drugs to treat TB. 

The invisible fire extinguisher

What you'll need

  • Bicarbonate of soda
  • Vinegar
  • Cup
  • Lit candle
  • Spoon

Top tip

Make sure you pour your gas out quickly after mixing your chemicals – it makes the experiment work better. But don’t tip it too far and make sure that the liquid will stay in the cup!

Step 1 Ask an adult to light the candle for you and be careful to keep the flame away from hair, skin and clothes. 

Step 2 Pour vinegar into your cup until it is around 2-3cm full.

Step 3 Add a spoonful of bicarbonate of soda to the cup.

Step 4 Allow it to fizz for a second, before asking your adult to help you ‘pour’ the invisible gas (NOT the vinegar and bicarb mixture) over the lit candle.

Step 5 Watch as your candle gets extinguished.

The science

  • The carbon dioxide that is produced in the reaction is denser than oxygen (density is a measure of the mass of the material, relative to the space it takes up).

  • Dense fluids sink through those that are less dense.

  • In this case, the carbon dioxide sinks down through the air, and the less dense oxygen floats above the carbon dioxide.
     
  • Without the oxygen, the wax can no longer burn. 

Real life science at the Crick

In this experiment, the removal of oxygen from the flame is signalled to us by the candle going out.

The cells that make up our bodies also respond to reduced oxygen levels by signalling.

One such signal is called HIF (hypoxia inducible factor) and whilst it ensures that healthy cells can respond appropriately if oxygen levels fall, HIF can also play a role in disease.

Crick scientists are investigating how HIF being active at the wrong times is involved in kidney cancer.