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Q:
Which of three liquids has the greatest mass?
water, oil and vinegar
- Armen (age 8)
Serrania elementary, California
A:
Hi Armen,
I think you may be asking about the density of the liquids. If you
have more of the liquid, you will have more mass. The density is the
amount of mass per unit volume. The density depends on what kind of
liquid it is, and a smaller amount on the temperature and pressure.
Oils are the least dense of the three you mention. Most oils have
a density around 90% that of water. They don't mix in water and will
float. Adding impurities to the oil may make it more dense however. An
example is the oil that gets drained out of cars -- it has lots of
heavy metal particles suspended in it which makes it a lot more dense.
But the fresh, clean oil should float in water.
Water has a density of about one gram per cubic centimeter (depending a little on temperature and pressure).
Household vinegar consists almost entirely of water, but with some
acetic acid molecules dissolved in it. In general, dissolving stuff in
water makes it more dense, making vinegar the densest of the three.
Tom
(published on 10/22/2007)
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