1. Aim: What is Density?
Do Now: What is the difference between mass, weight, and volume?
HW – R&H pp.5-6, A&E #10-18

2. Definitions
Mass- the amount of matter or the # of molecules in an object, cannot change, must be weighed to measure (grams).
Weight- the gravitational pull on an object, can change depending on where you are
Volume- the amount of space an object occupies. As temp. increases volume increases and as pressure increases volume decreases. Measure by water displacement (graduated cylinder), or lxwxh.

3. Density = Mass/Volume grams/cm3
Density- the concentration of matter in an object or how many molecules are squeezed into how much space.
Density = Mass/Volume grams/cm3
The density of a substance will always stay the same no matter the size or shape of the substance
The only way to change the density of a substance is by applying heat or pressure. However, if you change the density of a substance you have also changed what that substance is.

4. How to affect Density
Heat- if a substance is heated it makes the molecules move faster causing the substance to expand, therefore, decreasing its density.
Pressure- if pressure is put on a substance the molecules will be forced closer together, therefore increasing its density.
*If you do change the density with heat or pressure than you have also changed what the substance is.

5. Phases of Matter and Density
Most substances are densest when they are their coolest and in their solid form.
Water is the one exception. It is actually densest as a liquid of 4 deg. Celsius.
All substances will layer out by density with the most dense always going to the bottom and the least dense to the top.

6. Density and Floatation
Water has a density of 1 g/cm3 at 4 deg.c.
If an object has a density greater than 1 it will sink.
If an object has a density less than 1 it will float.
If an object has a density = 1 it will suspend in the middle of the water.

7. 9/19/14 Aim: How do we calculate Density?
Do Now:
A thumb tack is more dense than the human body, how is this possible?
How can you change mass, volume, density?
Calculate the density of a 3cm cube that weighs 50 grams.
HW: Track storms, Finish Lab

8. 9/22/14 Aim: What is a pollutant?
Do Now- R&H pp
1. What is a natural resource?
2. What is an environmental pollutant?
HW- Finish lab, A&E p.12, #29-39, Study all of Topic 1 for Quiz tomorrow.

9. Resources
Renewable Resource- a resource that will regenerate itself in the span of a human life.
Reusable Resource- a resource that can be used multiple times without having to discard it.
Recyclable Resource- a resource that can be reformed for a different use.