Easy kitchen science experiment for kids: can you dissolve an eggshell with vinegar, and make a naked egg? Fun science project for Easter, or any time of year!
This is a little activity that isn’t too complicated and is kinda cool. And there’s no need to duck to the shops, because you probably have everything you need at home already. We’ve done this activity three or four times this past fortnight – partly because the kids kept wanting to do it again and again, and partly because my youngest daughter Bumble Bee kept sabotaging the results. 🙂
I’ve found that a toddler is unlikely to be able to resist the urge to squeeze the naked egg, and/or drop it (as Bumble did, twice!), but you might be able to try this experiment with preschoolers and primary school kids. Jewel was 5 years, 3 months and Bumble was 2 years, 11 months when we did this activity.
How to dissolve the eggshell off an egg
You just need:
- an egg
- regular white vinegar
- a glass jar with lid
What to do
1. Add an egg to a glass jar.
It’s easier for young kids to hold the jar on its side, and gently place the egg inside. I’d recommend choosing a glass jar with a wide mouth, because your egg will swell slightly and may become too large for the jar opening (which is what happened to one of ours!)
2. Add vinegar.
Pour in enough vinegar to cover the egg, and then a little bit more. Our eggs floated at first, but they sank later on.
3. Look for bubbles!
Within a minute of adding the vinegar, tiny bubbles of carbon dioxide gas (the same gas that makes fizzy drinks all fizzy) appear on the eggshell. This is one part of the chemical reaction that is happening inside the jar.
4. Put on the lid, and let sit for a few days, or maybe a week.
The egg becomes slightly larger (because of osmosis). The brown eggshell colour pales. A layer of scum appears on the surface of the vinegar.If you’re keen, you could replace the vinegar after a day or two. Or if you’re like me, you might accidentally forget to do this bit….
5. Carefully remove the egg from the vinegar. Wash and gently rub off any remaining eggshell.
We found the eggshell wiped away, just at a light touch. It’s like wiping away wet chalk dust. (If your eggshell doesn’t come off easily, you may need to soak it in more vinegar for another day).
And now you have a shell-less (or naked) egg. 🙂
Naked eggs are cool. The inner membrane stays intact, so the eggs feel quite rubbery. You can gently squeeze them. The eggs are translucent, so you can see the yolk which, interestingly, always floats to the top.
If you drop your naked egg from a very low height (around one inch or so), you can probably make it bounce around like a rubber ball. (Be warned though, this will eventually get messy!)
The science behind dissolving eggshell in vinegar
This experiment is a classic acid-base reaction. Vinegar contains acetic acid. Eggshells contain calcium carbonate, which is a base.
The calcium carbonate in the eggshell reacts with the acetic acid in the vinegar to form a water-soluable compound, calcium acetate, and carbon dioxide (CO2) gas. This reaction dissolves the eggshell, but leaves the inner membrane intact, creating a naked egg.
When you first add the vinegar to the egg, if you look closely, you can see the reaction happening right before your eyes! Tiny bubbles of carbon dioxide gas (which is the same gas that makes fizzy drinks all fizzy) start to appear on the eggshell after just a few moments.
Bumble Bee is too young to understand all the chemistry just yet, but she still loved doing the activity. She wanted to take the eggs from the fridge herself. Put the egg in the jars herself. Pour the vinegar in herself. Put the lids on herself. Study the carbon dioxide bubbles herself. When the egg was ready, she wanted to wash the eggshell off herself. She wanted to hold the (now naked) egg herself. She even wanted to hold the camera so she could take photos of the egg herself. (She’s Little Miss Independent at the moment, which is great, even if it does mean a few broken eggs.)
We talked about how the eggshell feels when we first put it in the jar (hard and cold), and later how it feels when the shell was dissolved (soft and bouncy). She loved bouncing the egg on the table top and watching it jiggle around.
Jewel’s a little older, and is starting to comprehend the chemistry behind it all a bit more. Or at least comprehending that there is such a thing as chemistry behind it all. She’s starting to understand that the world is made up of elements, and that combinations of elements join together to form molecules (similar to how reading is made up of letters, and combinations of letters form words).
We’ve been talking about how some molecules are acidic and alkaline. She knows that there are things called ‘acids’ and that some of these acids are citric acid, stomach acid, uric acid and acid in vinegar. She knows that acids react with baking soda to cause a fizzy reaction, because of the dozens of Anzac Biscuits we’ve made over the years, and also, probably more prominent in her memory, because of the erupting volcano we made last month. But this is the first time that she’s experienced an acid-base reaction that doesn’t involve baking soda. While we were doing this activity, we chatted about how the acid in the vinegar reacts with the alkaline eggshell to dissolve it, and how the carbon dioxide bubbles are created as part of this reaction. Small steps to expand upon her interest, exposure and knowledge.
This activity is not meant to be viewed as edible. Since the egg has been pickled in vinegar, bacteria shouldn’t be an issue, but the raw egg will have absorbed vinegar (through osmosis), and so won’t taste very good, even if cooked. Let me put it this way – I don’t recommend eating it!
All kids’ activities on this blog require attentive adult supervision. Parents and carers will need to judge whether a particular activity is appropriate their child’s age and skill level. Click here for more information.
For more dissolving egg-spiration, you might like:
Or if you’re looking for another Easter science project, you might like:
- How to make your own Easter Egg shaped bubble wands (but what shape bubbles will they blow?)
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