Egg foam

Can you whip an egg white using only chemistry?

Difficulty:
Danger:
Duration:
15 minutes
Egg foam

Reagents

Safety

  • Put on protective gloves and eyewear.
  • Conduct the experiment on the plastic tray.
General safety rules
  • Do not allow chemicals to come into contact with the eyes or mouth.
  • Keep young children, animals and those not wearing eye protection away from the experimental area.
  • Store this experimental set out of reach of children under 12 years of age.
  • Clean all equipment after use.
  • Make sure that all containers are fully closed and properly stored after use.
  • Ensure that all empty containers are disposed of properly.
  • Do not use any equipment which has not been supplied with the set or recommended in the instructions for use.
  • Do not replace foodstuffs in original container. Dispose of immediately.
General first aid information
  • In case of eye contact: Wash out eye with plenty of water, holding eye open if necessary. Seek immediate medical advice.
  • If swallowed: Wash out mouth with water, drink some fresh water. Do not induce vomiting. Seek immediate medical advice.
  • In case of inhalation: Remove person to fresh air.
  • In case of skin contact and burns: Wash affected area with plenty of water for at least 10 minutes.
  • In case of doubt, seek medical advice without delay. Take the chemical and its container with you.
  • In case of injury always seek medical advice.
Advice for supervising adults
  • The incorrect use of chemicals can cause injury and damage to health. Only carry out those experiments which are listed in the instructions.
  • This experimental set is for use only by children over 12 years.
  • Because children’s abilities vary so much, even within age groups, supervising adults should exercise discretion as to which experiments are suitable and safe for them. The instructions should enable supervisors to assess any experiment to establish its suitability for a particular child.
  • The supervising adult should discuss the warnings and safety information with the child or children before commencing the experiments. Particular attention should be paid to the safe handling of acids, alkalis and flammable liquids.
  • The area surrounding the experiment should be kept clear of any obstructions and away from the storage of food. It should be well lit and ventilated and close to a water supply. A solid table with a heat resistant top should be provided
  • Substances in non-reclosable packaging should be used up (completely) during the course of one experiment, i.e. after opening the package.

FAQ and troubleshooting

I have the egg white from the last experiment. Can I use it?

Sure! One egg white may well be enough for all three experiments in this set.

How should I separate the egg white from the yolk?

There are several ways to separate the egg white from the yolk. Choose the one you like best!

First, you may already have a special tool for this at home. Ask your supervising adult about it, and use it if you do in fact have it!

If you don't have such a device, don't worry! Ask your supervising adult to use a sharp knife to break the egg over the plastic cup. Let the egg white drain, shifting the yolk from one half of the shell to the other.

You can also ask your supervising adult to hold the egg vertically and bore a small hole in the top using a needle or the tip of a sharp knife. Hold the egg upside down over a plastic cup and make an even smaller hole at the other end. Wait until all the egg white leaks out, then crack the egg normally over another container to deposit the yolk.

Also, if you have a clean, empty plastic bottle close by, you can use it to separate the egg white from the yolk. First, crack the egg into a plastic cup. Then, squeeze the bottle to force most of the air out of it. Third, bring the neck of the bottle to the yolk and stop squeezing the bottle. The yolk should be sucked into the bottle.

I want to repeat the experiment, but I don’t have enough NaHSO4 left.

Give it a try with the amount of solution you have. The experiment should still work!

Step-by-step instructions

Prepare an egg white and discard the yolk.

eggs-v2_egg-foam_en_iks-s-01

Add some sodium carbonate Na2CO3 and anthocyanin dye.

eggs-v2_egg-foam_en_iks-s-02

Now add some NaHSO4 to make the medium in the cup acidic. Watch what happens!

eggs-v2_egg-foam_en_iks-s-03

Disposal

Dispose of solid waste together with household garbage. Pour solutions down the sink. Wash with an excess of water.

Scientific description

What do soap bubbles in a bathtub, a latex mattress, and bread have in common? They are all foams! That is, they are made of gas bubbles trapped inside a liquid or a solid. There are basically two ways to make foam. One is to mix a substance with a gas, such as air, to make bubbles; another is to produce some gas inside a substance. You just did the latter with the egg white!

Sodium carbonate Na2CO3 is made up of components known as ions: two Na+ ions and a CO32- ion . CO32- isn't particularly stable in the acidic medium NaHSO4 creates; it decomposes, forming CO2 gas . Thousands of CO2 bubbles form in the egg white and make it froth nicely.

Water-soluble proteins, such as the ovalbumin in egg whites, tend to form quite stable foams. This is useful when making, say, meringues, but you also can find whipped proteins far outside your kitchen. For instance, proteins comprise up to three-fourths of sea foam.