Wednesday, 19 March 2014

Diffusion in egg white

This experiment will allow you to investigate how the rate of diffusion into egg white is affected by the concentration of the solution they are suspended in.

Equipment

Food colouring (red or black will work best)
Pipette
6 egg whites
Ice cube tray
Steamer or hot water bath
Ruler
Knife
Measuring cylinder
Water
6 beakers
Stopclock
Paper towels

Method

Distribute the egg white into the ice cube tray so that the wells are filled.
Either in a steamer or water bath (taking care not to let the water get into the wells) heat the egg white until it solidifies. Do not use a microwave as the heating is too vigorous and will result in air bubbles forming in the egg white.
Gently remove the egg white from the trays and use the ruler and knife to cut the egg white into uniform 1cm cubes - you should aim for at least 12 cubes.
Make 6 different concentrations of food colouring solution using 100ml of water and 1, 2, 3, 4, 5 and 6 ml of food colouring.
Place each solution in a different beaker and add at least two cubes of egg white.
Leave in the solution for 3 hours then remove the egg white cubes and dry the outside using the paper towels.
Carefully slice the cube in two and use the ruler to record how far the colour has penetrated into the cubes in each solution.

Risks

Steam or hot water used to solidify the egg white could cause a scald so take care to let the ice cube tray cool before handling.
Any spills should be cleared up as quickly as possible. Any breakages should also be carefully cleared up using a dustpan and brush.
Care should be taken when using the knife to make sure you do not cut yourself.