Tuesday, July 1, 2008
Our second day of chemistry and we are diving right in! Today we talked about "Properties" of matter. Two kinds... Chemical and Physical. Today we focused on Physical Properties. A property descibes a substance. It also allows us to identify it and put it into categories. There are two types of properties... "quanitative" which are properties that involve measurements and numbers; and "qualitative" which are those that do not involve numbers. "Patti is short" is qualitative... "Patti is 5'1" tall is quantitative". In chemistry we need to make both kinds of observations. Chemists all over the world compare quanitative properties with each other using the metric system of numbers. Our task today... investigate the physical property of "Density". Density is actually a relationship between two physical properties... mass and volume. Quantitativly, it is the ratio of a substances mass divided by it's volume. Qualitativly it represents how closely packed the particles are in a sample.
We investigated density in two ways today. The "Liquid Density Challenge" in which we compared the densities of 5 different liquids and arrived upon the proper order from least to greatest density. Then we performed the "Golf Ball Float" challenge where we add salt to water in measured amounts to make the golf ball float in the center of the container... once we know how much salt we added, we can figure out the density of the salt water solution. Whew! Busy day!