The egg in vinegar experiment, also known as the Rubber Egg or the Naked Egg experiment, is a classical science activity for kids. It is effortless to do because it requires just a couple of items that are readily available in your home.
Egg in Vinegar Experiment will certainly get your kids curious about learning the science that causes this mind-boggling effect!
Table of Contents:
Egg in Vinegar Experiment
As the experiment’s name suggests, the main items for this fun science experiment are raw eggs and vinegar.
Apart from this, you will also need:
- Small glass jar or flask
- Food coloring – optional
How To Do Naked Egg Experiment:
Step 1: Take a clean glass jar and place a raw egg carefully inside it.
Step 2: Gently add vinegar to the jar so there is enough vinegar to immerse the raw egg completely in the vinegar.
Step 3: Optional – Add some food coloring into the cup for added effects.
Step 4: Leave the egg in the vinegar for 48 hours that is 2 days.
Make sure you leave the cup with egg and vinegar in a place that cannot be reached by pets, toddlers, etc. so that it doesn’t topple and create a mess in the house.
Throughout 1st and 2nd day, encourage your kids to observe the changes emerging inside the cup. You can even get them to note down some details like:
- Color of the egg
- Weight of the cup at 6-hour intervals
- Any other transformations
Step 5: After about 24 hours, you will observe a layer of foam on top of the vinegar. The remaining liquid is mostly water. Drain off this water and replace it with fresh vinegar.
If you used food coloring, you will need to add it again to the fresh vinegar. Replacing vinegar is essential to make your naked eggs as you need to ensure there is enough acid to react with the egg shell to completely dissolve it.
Step 6: After 48 hours, take the egg carefully out of the vinegar and gently rinse it with water to remove any residue on its surface.
You will observe that egg shell has completely dissolved in vinegar leaving behind the egg white and yolk surrounded by a thin membrane.
Let your kids handle the naked egg and explore it in any way they want.
What does it feel like to touch? What does it smell of? Has it become bigger or smaller, or stayed the same size?
Provide children with a magnifying glass and flashlight to further investigate the minor changes in the naked egg.
It’s very likely they will be in awe and shock when they witness the transformation that the egg has undergone.
Related: Now that you have made rubber eggs, take a step further make Elephant Toothpaste.
What Happens When You Put the Egg in Vinegar?
Two activities take place during this experiment:
1. Chemical Reaction between Acetic Acid and Calcium Carbonate
The eggshell is made up of calcium carbonate, which is also the main substance you will find in chalk used on whiteboards. Vinegar is a solution of a weak acid, known as acetic acid.
The calcium carbonate in the eggshell reacts with the acid in vinegar to produce carbon dioxide. This reaction slowly “eats off” the eggshell until the vinegar completely reacts with the shell.
Technically, this is what happens
Egg Shell (Calcium Carbonate) + Vinegar (acetic acid) → Foam Floaties + Liquid Water + Carbon Dioxide Gas Bubbles
Here is the chemical equation for the chemical reaction that takes place:
CaCO3 + 2 HC2H3O2 → Ca(C2H3O2)2 + H2O + CO2
During the reaction with the eggshell, the inner membrane of the egg gets exposed to the solution.
The inner egg membrane is selectively permeable. This means it can allow specific molecules like water to pass through it. The water produced in the chemical reaction gradually moves inside the egg through a process called osmosis.
If you follow the optional step of adding food dye into the solution, the dye molecules will also move across the membrane along with the water molecules inside the egg.
Osmosis also causes the egg to increase in size and get bigger.
Results of The Rubber Egg Experiment
If your Naked Egg Experiment went according to the plan, you should see the following results:
1. After a few minutes of placing the raw egg in the vinegar, you will start observing bubbles forming around the eggshell. That’s carbon dioxide produced by the reaction between vinegar and the eggshell!
This bubbling can be observed as soon as the chemical reaction takes place and is a clear indication that the reaction has begun.
Related: What’s also fun are these bubbling Baking Soda and Vinegar Experiments for kids. Try them out!
2. Day 1 – You should start seeing a clear difference in the surface of the egg and the thick layer of foam on top of your vinegar.
This is the time when you replace the vinegar with fresh vinegar. If you had added dye to the vinegar, you would see the egg turned into that color too.
Kids will be curious to pull out and have a poke at the egg, so you may have to convince them to be patient for a one more day.
You could also try to keep their brains engaged in a fun side activity by asking them to observe the size of the egg – has it gotten bigger or smaller?
Ask them to predict what will happen to the egg when they finally take it out after 48 hours.
3. Day 2 – At this stage the eggshell would be gone and the raw egg would have turned into a rubber egg.
When your kids take the egg out, they would find it rubbery and squishy. Don’t be fooled for once that the egg is soft and rubbery all the way through.
The egg membrane is quite thin and fragile, so the naked egg needs to be handled carefully. If you squeeze the rubber egg too hard, the egg will crack and spill the egg yolk and egg white all over the place.
It’s best to make sure you’ve chosen a location that’s easy to clean before letting your kids handle the bouncy egg.
Related: Set up a handy science lab for kids at home where they can experiment and investigate freely to help them learn.
Studying Naked Eggs
It’s time to poke inside and reveal what’s been going on inside the naked egg!
When investigating the bouncing egg (or naked egg), kids are certainly going to make mistakes, and that’s when the real learning happens.
If you’ve got ample resources around the house then it’ll be ideal to prepare several naked eggs for experimental purposes.
Try some of these tests to study naked eggs:
1. Examine The Different Parts Of The Egg
Slice open the egg onto a flat dish to observe the parts of the egg. Get children to see the water that has been absorbed. You will also be able to see the rubbery egg membrane in the dish.
If you dye the egg, you will observe the egg white has been coloured with the food dye but not the egg yolk. Can you guess why?
That is because of Osmosis. The membrane of the egg allowed the dye to pass through it into the egg white, making it the color of the food dye.
However, the egg yolk is surrounded by a special membrane that does not allow the dye to pass through it into the yolk.
2. Bury The Naked Egg in Salt
This will cause osmosis to take place again, but this time in the reverse direction. That is from the inside of the egg to the outside.
Simply bury the rubber egg in salt for a few hours. After several hours, carefully take the egg. You will observe the egg has shrunk.
Quiz them and ask what they think would happen if they replaced salt with corn syrup and put naked egg in corn syrup.
Or challenge your kids to predict what would happen if you put it back in a glass of water.
Hint: Osmosis is going to take place again, and water will seep into the egg!
3. Put The Naked Egg in Alcohol
If you want your mind blown, you should place the naked egg in an alcohol solution like ethanol. Ethanol will seep through the egg membrane and react with the egg proteins inside.
It will literally cook the egg! After several hours, slice it open and see this for yourself. Make sure kids are doing this under adult inspection, as alcohols are highly flammable substances.
Do Naked Eggs Smell?
The simple answer is no! Naked eggs do not smell or emit any odour that may cause discomfort. However, if you crack the rubber eggs open, they do smell like the usual eggs.
Can You Eat Naked Egg?
We would not recommend eating naked eggs for two reasons. Firstly, eating raw egg is not recommendable. Raw and undercooked eggs may contain Salmonella, a type of harmful bacteria, which can lead to food positioning.
Secondly, the amount of vinegar the egg has absorbed during the process would make the rubber egg quite disgusting to eat. So, it is best to keep these rubber eggs for experimentation and avoid eating them.
Experimentation is a great way to get your kids excited about science. Your children will benefit a lot if they start to develop critical thinking skills from a very young age.
If you assume that you need complicated equipment and chemicals to carry out science experiments for kids, that’s a myth. The egg in vinegar experiment is a great example. Now go and make your own bouncy eggs and test if the rubber egg experiment really works!