Oil and Water Oil and Water Have you

Oil and Water

Oil and Water Have you ever tried mixing oil and water? They like to separate out, even if you shake them really hard. This is because water and oil have two different properties. Water is hydrophilic (hydro = ‘water’ and philic =‘like’) Water likes mixing with things that are water based or other hydrophilic things. Oil is Hydrophobic (hydro = ‘Water’ and phobic = ‘hate’ or ‘dislike’) Oil likes mixing with things that are not water based or other hydrophobic things. Add oil and water (you can add a drop of food colouring to the water if you like) to a tube. Mix them up by shaking the bottle – what happens? What happens if you add a bit of washing up liquid and try mixing them? Detergent likes both water and oil so can allow them to mix, forming an emulsion.

Mixing Milk and Colour. 1. Pour enough milk in the dinner plate to completely cover the bottom to the depth of about 1/4 inch. Allow the milk to settle. 2. Add one drop of each of the colours of food to the milk. Keep the drops close together in the centre of the plate of milk. 3. Find a clean cotton swab for the next part of the experiment. Predict what will happen when you touch the tip of the cotton swab to the centre of the milk. It’s important not to stir the mix. Just touch it with the tip of the cotton swab. Go ahead and try it. Did anything happen? 4. Now place a drop of liquid dish soap on the other end of the cotton swab. Place the soapy end of the cotton swab back in the middle of the milk and hold it there for 10 to 15 seconds. 5. Add another drop of soap to the tip of the cotton swab and try it again. Experiment with placing the cotton swab at different places in the milk. What do you see?

Mixing Milk and Colour. Now try the experiment again but use water, semi skimmed milk and skimmed milk instead of full fat milk. What do you need to keep the same to make this a fair test? What do you observe? Why do you think this is? Liquid used Observations