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This is super fun science experiment that makes shells disappear in vinegar.
And in doing so, very visually introduces kids to acids, solutions, minerals and the strange ways substances react with one another.
The experiment is simple enough to appeal to pre-K kids but can also be used to introduce more complex ideas to 5th grade and secondary school students.
It’s a great follow on experiment from the popular vanishing egg experiment … +Science Sparks shows you how to do this if you haven’t done it before … but is powerful in it’s own right.
What You Need
- Sea shells in various shapes & sizes that you don’t mind vanishing!
- Empty snail shells (give them a rinse to get any left over gunk out)
- Cliff chalk (nice to have but not essential – board chalk won’t work)
- Assortment of hard & soft “control” objects e.g. sand, stone, soil, fabric, grass, leaf
- White vinegar
- Lemon juice
- Assortment of “control” liquids e.g. water, milk
- Litmus paper to test the acidity of the vinegar, lemon juice & other liquids
- Jam jars are fine but if your kids love experiments it’s worth getting some pyrex measuring beakers
What’s Going To Happen?
Ask your kids what they think will happen to sea and snail shells if kept in vinegar over night.
If your kids have made egg shell disappear they may “guess” that the acetic acid in vinegar will dissolve the shells which like egg shells are made of calcium carbonate.
Also get them to “guess” what will happen to:
- the shells in other liquids
- other objects … some hard & some soft … in vinegar
The basic version of this experiment is simply to …
- Put a sea shell and a snail shell in beakers of vinegar and leave over night
- The snail shell will disappear
- The sea shell will be worn down but still intact … replace the vinegar and leave again
- The sea shell will bubble again in the fresh vinegar and wear down further
- A thin shell may disappear in the second lot of vinegar or may need another fresh dose before it finally … magically 😉 … vanishes …
This extended version of the experiment lets you talk about acids and how they weaken some apparently “hard” objects but are themselves “neutralised” in the process …
… you don’t have to do the whole experiment in one go but I have included lots of permutations you could include at different times depending on what captures your child’s imagination …
- Feel the shells and your control objects and think about whether they are hard or soft
- Put a sea shell(s) and snail shell(s) in separate beakers and cover with vinegar
- Put a shell in separate beakers of water, milk and lemon juice
- Put some other objects in beakers of vinegar
- If you’ve got litmus paper, test the acidity of each liquid … with younger kids you could just talk about the colour the paper turns, with older kids record the pH number …
- Observe the shells and other objects … you should see lots of small bubbles around the shells in the vinegar and the lemon juice
- Leave the experiments over night …
- The shells in milk and water & other objects in vinegar will be unchanged
- The snail shells in vinegar and lemon juice will probably vanish …
- Most sea shells in the vinegar & lemon juice will be worn down but intact
- Talk about how the results show that the acidic liquids … which turned the litmus paper purple … were able to dissolve some hard objects e.g. the shells but not others and had no impact on “soft” objects
- Now test the acidity again with the litmus paper … the control liquids should be unchanged, the snail shell vinegar will probably be less acidic and the sea shell vinegar near enough neutral
- Talk about how the shells and the liquids have “interacted” and that the shells have actually “changed” the vinegar so that it has lost its acidic power …
- Replace the sea shell vinegar with some fresh vinegar … the shell will start bubbling again and wear down further but probably won’t dissolve completely …
- Keep testing the vinegar with litmus paper to see how quickly it is changed by the shell
- Most sea shells will neutralise the second lot of vinegar but a third fresh lot will finish them off 🙂
From the experiment children will be able to talk about …
- Acidity of liquids
- How to measure acidity
- How acids dissolve some “hard” objects but leave other hard & soft objects intact
- How the interaction of some acids with the calcium carbonate in shells, dissolves the calcium carbonate but also neutralises the acid