Relief Teaching Ideas

Sharing ideas to help make relief teaching fun, enjoyable, and meaningful.

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Colour Changing Milk

Was the classroom teacher unexpectedly away & unable to leave set work? Can you see that science is one lesson that is usually scheduled for the day?
This is an easy science experiment that I originally saw on the Steve Spangler website. It is suitable for all age levels – these photos were taken while I was doing this activity with my 2 year old!

Head down to the cafeteria or canteen & see if you can buy some milk. You should also be able to find suitable containers, food dye & a little dish soap from the neighbouring classroom teachers.

Colour Changing Milk

A shallow bowl, plastic plate or a tray (like a cookie baking tray)
Food colouring (at least 3 different colours)
Whole milk – low fat milk will not work for this experiment
Liquid dish washing soap

-Carefully pour the milk into the tray so that it just covers the bottom.
-Add about 6-8 drops of different coloured food colouring onto the milk in different spots.
-Add about 5 drops of the liquid soap onto the drops of food colouring and watch what happens. (You could also dip a cotton bud soaked in dish liquid.)

The main job of dish soap it to go after fat and break it down. Usually the fat is on dishes from the food we eat, but fat is also in whole milk. When you drop the liquid soap onto the tray, it tries to break down the fat in the milk. While it is doing that, it causes the colours to scatter and mix creating a colourful display.

– Does the shape of the tray affect the reaction? Give groups of students different shaped/sized containers to try it out.
– Is the result different when you drop the food colouring around the edge of the tray? In the middle?
– Are the results different with low fat milk? Flavoured milk?

Have students write up the experiment, illustrate & label the results.