Growing Gummy Bears – Osmosis & Diffusion

You may have already tried out our Store Cupboard Science Experiment ‘Growing Jelly Babies’.

This is a similar experiment to grow Gummy Bears, which demonstrates osmosis.

Growing Gummies.pdf (coxsciencecenter.org)

Instructions

You will need:

gummy bear jelly sweets
3 bowls
hot water
salt
sugar

We made concentrated solutions by pouring hot water into the bowls (ask an adult to help) and then mixing in salt or sugar and stirring well.  We allowed the 3 bowls to cool and labelled them as salt, sugar and water.  Once cooled we added the gummy bear sweets (we placed 2 per bowl) into bowls of concentrated salt and concentrated sugar solutions and also into a bowl of just water.

We left the bowls covered overnight to see what would happen.

As you can see from the photo the gummy bears in the water in the middle had grown the biggest, the ones in the sugar solution stayed the same and the salt water ones had shrunk a little.

But why?

The Science Bit

We made solutions by dissolving the sugar and salt into water.  The amount of the stuff, here the sugar or salt, dissolved into a solution is called the concentration.  We made concentrated salt and sugar solutions.  Water molecules are constantly moving (as we showed in Growing Jelly Babies )

The water moves from a solution with a lower concentration to one with a higher concentration. This is a process called osmosis.

The gelatine structure of the gummy bear allows water molecules to squeeze in between its molecules and join them.  This is by a process called diffusion.  The additional water molecules cause the jelly sweet to grow and swell.  When we place that swollen jelly sweet into a salt water mixture , the salt particles diffuse into the gelatine and take the place of the water molecules, so the jelly bear loses the water molecules and shrinks to a smaller size.

You can also find out more about osmosis & diffusion here

Comparing diffusion, osmosis and active transport – Transport in cells – Edexcel – GCSE Biology (Single Science) Revision – Edexcel – BBC Bitesize

BBC Sounds – Bitesize GCSE Biology, Series 1: The Cell, 7. Diffusion, osmosis and active transport