Density is the term used to describe the relationship between the mass of the particles and their volume for a given unit of matter. You determine the density of a unit of matter by determining the mass (in grams) and dividing it by its volume (in ml or cm 3). Therefore, when a piece of matter has large mass and comparatively small volume the density is high…we call such things “heavy” or “heavier”. When a piece of matter has small mass compared to large volume the density is low…we tend to call such this “light” or “lighter”. The equation for density is D = Where D = Density m = Mass (g) v = Volume (ml or cm 3 ) m v

Different liquids have different densities. You can compare densities of different liquids by observing how an object floats in each. If the liquid is much denser than the object, most of the object will be above the surface of the liquid If the object is only slightly denser than the object, more of the object will be under the surface. A hydrometer is a tool that allows a researcher to compare densities of liquids in this fashion. Place the hydrometer in each of the graduated cylinders and answer the questions in section 2 of your handout.

Archimedes discovered displacement when he jumped in a bath…he then ran down the street naked screaming Eureka! When a solid object is placed in a fluid, it displaces its volume of the fluid material. For example, if you placed 1 cubic meter (1 m 3 ) object in a full container of water, 1 cubic meter of water would flow over the sides of the container. This is true for any fluid. We can use displacement to determine the volume of matter. If we can also determine its mass…we can determine its density. Eureka!

Section 1) a) Place the Regular Pepsi and Diet Pepsi in the beakers provided. You will note that they have different densities. Explain why the Diet Pepsi floats compared to the Regular. b) Using the Triple Beam Balances provided, determine the approximate density of both Colas. Diet Pepsi v = _____ m = _____ D = _____ Pepsi v = _____ m = _____ D =_____ Section 2) a) What is a hydrometer? b) Rank the densities if the three liquids tested in station c) How does a hydrometer work? Think of the number and size of the particles in the solution with the highest density compared to the lowest.

Section 3) a) Place an ice cube in the beaker 1. Record your observations below. b) Place the same ice cube in beaker 2. Record your observations below. c) Can you explain the differences between how the ice cube responds in beaker one compared to two? Section 4) a) What is Displacement? b) Determine the densities of one of the weights provided using the displacement method record the values below. Use the Triple Beam Balance to determine the mass of the weight. Volume = Mass = Density =