Today is Tuesday, December 4, 2012 Homework: Read Chapter 7, Lesson 3 Chapter 7 H.W. Packet assigned (due Monday) Warm Up: In your table groups, discuss what it means to float? To sink? When does something float or sink? HINT: think about weight, density, and mass – like we discussed yesterday in class

Goal for Today SWBAT demonstrate the ability to explore the effect of temperature and salt concentrations (salinity) in water by comparing the layering effect of water with different densities.

A little bit of review….. Yesterday we said that….. I can’t quite remember!!!! Is cold water denser than warm water (cold water is heavier, it sinks) or is cold water less dense than warm water (cold water is lighter, it rises)? Which one of these two is true: Saltwater is denser than freshwater, making it heavier Freshwater is denser than saltwater, making it heavier

More review….. Weight = The amount of downward pull exerted on an object (gravity). Your weight is different on Earth than it is on the Moon because the Moon is smaller than Earth.

Mass = The total amount of matter in an object Mass = The total amount of matter in an object. Unless you go on an extreme diet or you suddenly start packing yourself full of unhealthy amounts of food, your mass does not change no matter what planet you are on.

Density = Mass per unit of volume Density = Mass per unit of volume. Density is the measure of how tightly matter is “packed into” an object. A marble made out of glass will be lighter than a marble the same size made out of solid gold, because gold is a very dense metal.

So we don’t run out of time…. Let’s jump into doing the lab! As we do the lab you will notice that layers of water form on top of each other. Remember our key term “DENSITY” as you do the lab and think of how “DENSITY” plays a role in why the water forms layers the way it does.

Closing it up…. Review the terms “WEIGHT”, “MASS”, and “DENSITY” with your table group members. What water do you think was the most dense in our lab today?