# SJ #11 “Temperature and Density Notes”

SJ #12 “Temperature and Density” Lesson 5 p.43 * TEMPERATURE : the amount of ENERGY that the molecules in a substance have. -measured with a thermometer “therm” = heat “meter” = measure -EX: high temp.

fast moving, high energy molecules low temp.

slow moving, low energy molecules * HEAT : the TRANSFER of ENERGY from a hotter object to a colder object. (“transfer” means to move) --add heat

temp. increases --remove heat

temp. decreases p. 43 “Changing Temperature, Changing Density” -MOST matter increases in VOLUME when it gets hotter

EXPANSION *EX: if you heat a gas, particles will expand, but MASS STAYS THE SAME

gas will be LESS DENSE -MOST matter decreases in VOLUME when it gets colder, CONTRACTION *EX: if you cool a gas, particles will contract, but MASS STAYS THE SAME

gas will be MORE DENSE

**WATER IS AN EXCEPTION! **H 2 O actually expands when it freezes, so it becomes less dense and floats. **This is why pipes burst a lot in winter.

**Other exceptions: gallium, bismuth, acetic acid, antimony, and silicon, due to their molecular geometry. They form “tetrahedral lattices”, a fancy term for a kind of crystal. *Eureka! Episodes 19, 20 & 21 *Expansion & Contraction 1) 2) 3) *Measuring Temperature 1) 2) 3) *Temperature vs. Heat 1) 2) 3) + 1 drawing *Read p. 44 45 “Measuring Temperature By Degrees” --write 10 facts *3 from p. 44 *7 from p. 45 *What is the most interesting idea you read in this article? Answer in a complete sentence!