Separation of salt
Part 1 of 3: Setting up
1. 1
Measure out the sand and salt. How much of this mixture you make is up to you,
but a good rule of thumb is for it to be composed of about 80% sand and 20% salt.
This isn’t a strict ratio, and some people like to use equal parts sand and salt for
greater visual impact.[2] Whatever quantities you use, make sure to note down how
much sand and salt you are starting with before you combine them.[3]
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The more salt you use, the more water you will need to dissolve it, and the
more water you use, the longer you will need to wait for the water to
evaporate. In other words, the more salt you use, the longer this experiment
will take.
The sand will be significantly heavier once it is wet, so for easy comparison it
is a good idea to measure its mass rather than its weight.
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2. 2
Mix together the two ingredients. Pour the sand and salt into a saucepan. Stir with a
spoon or a fork until they are well combined.[4]
3. 3
Add water. Make sure to use enough for all of the salt to dissolve into. The exact
amount you need in order to avoid saturating the water without dissolving all of the
salt will vary based on a number of factors, but you should be able to eyeball it pretty
easily based on the amount of salt you used.[5]
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A good rule of thumb is to have about an inch of water on top of the sand and
salt mixture.[6]
If in doubt, it’s better to have a little too much water than not to have enough.
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Part 2 of 3: Isolating the Two Ingredients
1. 1
Dissolve the salt. Turn on your burner on to a medium to medium-high heat. Stir the
mixture to help the salt dissolve more quickly. When it is completely dissolved,
remove the water from the stove.[7]
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You can accomplish the same thing by putting the sand, salt, and water
mixture into a mason jar, screwing the lid on it, and shaking it. This will take
longer, and require more physical exertion.[8]
2. 2
Remove the sand from the liquid. Pour the mixture through cheesecloth. Keep a
bowl underneath it to catch the salty water. Wring as much of the water from the sand
as you can. Set the sand aside.
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A coffee filter in a funnel can also be used for this, although it will take some
patience, as it will take more time for the water to drip through the paper.[9][10]
3. 3
Pour the water and salt mixture back into the pan. Set it back on the heating
element. Turn the burner to medium-high to high heat. Do not cover the saucepan.[11]
4. 4
Allow the water to boil away. You do not need to stir it. As the water evaporates, the
salt will gather in the bottom of the pan.
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You can also simply let the water evaporate overnight.[12] This will work best
if you used small quantities of the ingredients, otherwise it will take a long
time.
5. 5
Collect the salt. Use a spoon to scrape the salt out of the saucepan. Set it aside.
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Part 3 of 3: Reviewing and Debriefing
1. 1
Measure how much sand you now have. Some of it may stick to the cheesecloth, so
you won’t have precisely the same amount of sand you started with down to the last
grain, and it will be heavier now that it is wet. You should have very close to the same
amount of sand you began with, though.
2. 2
Measure how much salt you now have. Some of it may still be caked to the
saucepan, or lingering in the water that is still in the wet sand. As with the sand,
though, the quantity should be extremely close to what you began with.
3. 3
Think about the experiment. Salt and sand look pretty similar, but this activity
shows that there are some pretty significant differences between the two substances.
We can learn some interesting things by considering a few questions.[13][14]
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Why does it work?
Could you do the same thing to separate sugar and sand? What about sugar
and salt?[15]
How might you get more exact measurements?
Do you think the salt is pure, or might it still be contaminated?
How do you think this experiment would change if you used room temperature
water?