Colour-Layered Straw
Science Trick

This quick and easy science "trick" is fun and interesting and uses materials you may already have around your home.
Remember, it's always a good idea to practice at home first!

Suggested Materials:

* 1 x drinking straw (clear-coloured, if possible)
* 1 x full cup of water with food colouring added (eg. red)
* 1 x full cup of water with a different food colouring added (eg. blue).
* Stir 1 tablespoon of salt into this second cup
* 1 x empty plastic cup

Suggested Instructions:

Step 1: At home, place your straw about 3 centimetres into your red water in an upright position.

Step 2: Place your index finger firmly over the top of the straw and lift the straw out of the red water. You will see red water trapped inside the straw.

Step 3: Without removing your index finger, move your straw to your blue water and place your straw about 6 centimetres into the blue water in an upright position.

Step 4: Very briefly lift your index finger off the top of the straw and immediately put it back down again.

Step 5: Lift your straw out of the water and you will see a band of red water and a band of blue water trapped inside your straw. Show your audience your colourful straw (without removing your index finger).

Step 6: Move your straw over the top of the empty plastic cup and take your finger off the top of the straw. Watch the coloured water come rushing out.

Step 7: You may like to practice this trick a few times at home before trying it at school.

Step 8: At school, repeat Step 1 to Step 6.

Note: You can try for a third layer of colour by stirring 2 tablespoons of salt into a third cup of water with food colouring added eg. green. Simply repeat Step 3 to Step 5. During Step 3, place your straw about 9 cm into the coloured water. This third layer can be more difficult to make a success. But it's worth a try!