Today

• Hand in work• Check the list in the back, if you owe

something.• Get out a half sheet of paper, PUT YOUR

NAME ON IT, share the other half.

• When bell rings the quiz will start and you will have 1 minute per question to answer.

Question 1

• What 3 elements makes up the troposphere?(use your ESRT)

Question 2

• What layer of the atmosphere has most of the water in it?

Question 3

• What is the temperature at the Tropopause?

Question 4

• What happens to pressure as you increase altitude?

Answers

• 1.) Oxygen (21%), Nitrogen (78%) other (1%)• 2.) Troposphere• 3.) -55oC• 4.)Pressure decreases when altitude is

increased.

• 10 points off for each incorrect answer!• 100- points = the grade.

Vocab

• Density• Mass• Volume• Graduated Cylinder • Scale or triple beam balance

Density

The first really important idea!!!(coke and diet coke?)

Why is density important?

Earth Science is the study of the planet.Ask yourself this:• Is there a lot of oil to use on this planet? How do

we get it out of the ground?

• Should I dump chemicals into the water we use to drink? How do the chemicals mix?

• How to I clean up these messes, if they are every made?– How do you clean up if you spill oil?

• How does weather interact with the earths crust?

Density• What is the formula for Density? (Yes you do know)

• What is your Mass?– How much stuff makes you.

• What is you Volume?– How much of you there is.

• So your Density is the amount of Mass divided by the Volume you take up– It is how tightly pack the molecules are in a space!

M ---------D * V

Cool info (layers)

• Air = 0.0012 g.mL• Liquid Water (4oC) = 1.0 g/mL• Ice = 0.9 g/mL• Iron = 7.9g/mL• People= 1.0 g/mL• Plastics = vary form 0.8-1.3• Earth = 5.5 g/mL• Saturn (yes the planet)= 0.7 g/mL• Black hole 400,000,000,000,000 g/mL

Icebergs (dead ahead)

• If ice floats (less dense than water) where is most of the ice then?

• Only 10% of the whole berg is above water level why?

Does density change?

• The question is does density change?– I start with a block of wood and cut it.– What do I have then?

–Density doesn’t change with size!!

– Same thing with rocks, minerals counties and people.» If I cut you arm off your mass and volume would

be lower equally, so your density would be the same! Let’s try it!

Can I change Density? (yes)

• Heat– By adding heat I change the energy level of matter

causing the volume to change.• Pressure– By squeezing an object the volume is changing.

• Think about it!– If I heat a rock up till it melts what happens?– If I squeeze a rock what happens?

Calculating and measuring

• Density is mass over volume• How do I measure Volume?– L*W*H (cm3)– Graduated Cylinder (mL)

• How do I measure Mass?– Scale (g) or triple beam balance

• So if D=m/v what are the correct units for density? M

---------D * V

Relate density to weather

• Warm air does what compared to cold air, because it is less dense?

• Object usually do what when they freeze?– Heat up?

Practice• Find the density if the mass is 10 g and the volume is 1

mL?– Formula?– Answer?

• Find the volume if the mass is 20 g and the density is 10 g/mL?– Formula?– Answer?

• Find the mass if the density is 5 g/mL and the volume is 10 mL?– Formula?– Answer?