This is not a project or experiment. It is interesting to read, it is about something we all need to know, and the person who wrote it might cry if you don't read it.

When we checked the relative weights of water and other liquids, we saw that liquids do not all weigh the same. We don't really know why that is, but I bet we'll find out soon.

The key word here is "density." Density is the relationship between the volume and the weight of any substance.

Alcohol, for example, is less dense than water, and, therefore, one liquid ounce of alcohol does not weigh as much as one liquid ounce of water. Molasses is more dense, and one liquid ounce of molasses weighs more than one liquid ounce of water. The density of water is used as a standard for measuring the densities of other liquids.

We would see the same things about density if we compared the weight of a brick to the weight of a block of wood that is the same size as the brick. They are both the same size, yet one is much heavier than the other. The brick is more dense than the wood. A block of styrofoam of the same size as the wood block and the brick would be lighter than the wood, because wood is more dense than styrofoam.

There are projects in here that help us see the relationships between water and other liquids, as well as the scale-weights of water and other liquids. We don't need to do them right this minute; we can do them later, or, maybe we already did them!

Here's a little tidbit of information you can chew on for awhile:

The ratio between the density of a material and the density of water is called specific gravity.

Think about it.