Density is a measure of how closely packed molecules are in a substance. Liquids with molecules packed closely together have a higher density than those with more space between molecules. Density can be compared to population density - a more densely populated classroom is like a higher density liquid. The density of a substance is a physical property that does not change with amount. Salt water is more dense than pure water, so it would sink below the water. Different liquids in a layering experiment do not mix because the densities cause them to separate into distinct layers.

1. LIQUID DENSITY
December 13, 2011

2. Your objective
 Understand what is ‘Density’
 Compare the density of liquids through
layering

3. Density
Density is a measure of how closely packed the
molecules of a substance are.
If the molecules are all packed in close, the
liquid is high density.
If the molecules have lots of space between
them, the liquid is low density

4. You can also compare this to population density to
better understand. For this example, think of
yourself as a molecule:
When it is just the grade 5s in our classroom, there
are only 10 students (or molecules). This is like
low density.
When the grade 4 and 5 students are all in the
classroom there are 20 molecules in our
classroom , which is higher density.

5.  Do you know what it would be called if the
classroom was so full of molecules that we
could not fit anymore molecules in?
 A) Solvent
 B) Saturated
 C) Substance

6.  The right answer is:
 B) Saturated

7.  Density is a physical property of a substance.
 A physical property is something about a
substance that can be measured.
 The density of a substance is the same
whether there is more of the substance or not.

8.  The opposite of physical property is chemical
property.
 A chemical property of water is that it is NOT
combustible.

9.  Watch this video on layering liquids
 http://www.youtube.com/watch?v=B3kodeQnQ
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10. Video Questions
Answer the following questions:
1. What is Density?
2. The density of water is 1. Can you think of
a liquid that would be less then the density
of water?
3. Salt water is more dense than pure water.
Does this mean the salt water would sink or
float?
4. In the seven layer experiment, why did the
different liquids not mix together?