Blue egg white

Explore the effect of copper sulfate on egg proteins!

Difficulty:
Danger:
Duration:
20 minutes
Blue egg white

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 still 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 added more than 15 drops of CuSO4. What should I do?

Don't worry! Continue the experiment.

Can I use one syringe for the egg white and water?

Yes, you can use one syringe. The experiment will still work.

In addition, we recommend you keep the syringe after the experiment and wash it with water. You’ll need it to repeat the experiment in the future!

Should I shake the test tube?

No, this isn’t necessary. You’ll get better results by gently turning the test tube upside down and right side up 3-5 times.

Step-by-step instructions

Egg whites mostly consist of ovalbumin proteins and water. Prepare an egg white and discard the yolk.

eggs-v2_blue_en_iks-s-01

Proteins can be very sensitive to chemical and physical changes in the environment. Let's see if CuSO4 has any effect on the egg proteins.

eggs-v2_blue_en_iks-s-02

The Cu2+ ions from CuSO4 turn the egg white into blue slime! The effect is even more dramatic when you make the medium more alkaline by adding Na2CO3.

eggs-v2_blue_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

Protein molecules are very large. A single ovalbumin molecule  from the egg white, for instance, is about 2000 times heavier than water ! And even this is nothing compared to the largest known protein (titin, in your muscles), which is another hundred times heavier than ovalbumin.

Although such a large molecule may look intimidating, it, like all protein molecules, is just a long chain made of relatively small parts known as amino acids. There are 22 kinds of amino acids, each with special parts to bind with other amino acids  and a "radical"  specific to each amino acid type.

Long protein molecules in living organisms are normally folded in a special way . This folding is crucial for a protein to function properly. Some compounds, such as CuSO4 , easily disrupt normal folding, making proteins stick together.