10. Rainbow Fizz

In this activity you will be using your senses to make observations.

You will also need to follow the instructions carefully.

If you are careful you should be able to produce a rainbow effect in the tube.

Method

A The boiling tube contains sodium carbonate. Write down a description of the appearance of sodium carbonate.

B Tube 1 contains water. Add the contents to the boiling tube. Feel the outside of the tube. Describe what you can see and what you can feel.

C Shake the tube, describe what you can see now.

D Tube 2 contains universal indicator. Smell the tube carefully by wafting the smell towards you. Describe the appearance and the smell of the liquid in the tube.

E Add the universal indicator to the boiling tube. Observe without shaking, what do you see?

F Now shake the tube. What do you see now? What type of substance is sodium carbonate?

G Tubes 3 and 4 contain ethanoic acid. Smell each tube carefully by wafting the smell towards you. Describe the smell and the appearance of the liquid in the tubes.

H Add the contents of tube 3 to the boiling tube. Do not shake the tube, describe what happens.

I Very carefully pour the contents of tube 4 into the boiling tube. You may find it helpful to tilt the boiling tube slightly as shown in the diagram.

Do not shake the tube. Describe what you see.

J Explain why you get the rainbow effect...

Can you:

• • carry out a safe investigation.

  • make careful observations.