1. DO NOW
Which has more matter, a 10 cm piece of Styrofoam or a 10 cm piece of metal?

2. Metal Why? Metal has more matter in the same amount of space.
The matter must be closer together in the metal.
The matter in the metal is more dense.

3. What does Density measure?
Density: Measure of how compact (close) the molecules of a substance are.

4. Which is more dense? Mass = _______ molecules Volume = ______ cm3
Density = _______
Mass = ______ molecules
Volume = _____ cm3
Density = _______

5. Density Equation
Density is a measure of the objects mass in a particular volume.
Density = Mass D = M
Volume V

6. Example mass = 200 g D = m Volume = 25 mL V Density = ? D = 200 g
D = 8 g/ml

7. Rearranging the Density Equation
You can rearrange the equation to solve for mass or volume.
M = ?
V = ?
As long as you know 2 variable you can solve for the third.

8. Density Triangle 1. Cover what you are looking for with your finger.M D
1. Cover what you are looking for with your finger.
2. The remaining letters tell you what mathematical function to perform. M
D V
M =
V = DV

9. Practice
What is mass of a substance that has a density of 4.5g/ml and a volume of 20ml?
M=DV (4.5g/ml)(20ml) = 90g
What is the volume of a substance that has a mass of 675g and a density of 12.5g/ml?
V= M = 675g = 54 ml
D g/ml

10. DO NOW: On a new piece of paper
Problem: If I cut a block of wood in half what happens to the density of the wood?
Hypothesis: If I _____ then _____ because _________________.

11. Materials & Procedure List the materials you will need.
Write out the steps you will do to test your hypothesis.

12. Density Data Table Large block wood Mass = Volume = Density =
Half block wood
Mass =
Volume =
Density =

13. Conclusion Analyze your data. Does your data support your hypothesis?
What could you have done better in this experiment? (experimental error)
There’s always something!

14. Sum it up
The density of a substance will stay the same regardless of the size of the sample!
So, if it have a 2 cm cube of oak or an entire tree the density will be ____________.
the same!!!

15. DO NOW
Why did the density of half the block stay the same as the whole block?
(hint: look up definition of density)

16. Density Table Material Acrylic Aluminum Brass Copper Oak Pine
Polypropylene
PVC
Steel
g/cm3
2.70
8.96
7.9

17. Density of Solids
Are all solids the same density? No
Steel
Glass
Wood

18. Do all liquids have the same density
Do all liquids have the same density? Which do you think is more dense, water or oil?

19. Do all gases have the same density?
No.
Which gases are less dense than air?
Helium! It floats in air.
AIR

20. Which of these materials would you guess is the least dense and most dense?
A B C
Least
Most

21. DO NOW How can we estimate the density of an object?
If I mix oil and water what will happen?

22. Comparing Density
We can estimate the density of an object by comparing it to another object with a known density.

23. WATER Density of Water = 1 g/ml
If an object floats what can you say about its density?
If an object sinks what can you say about its density?

24. Density is < 1 g/ml Density = 1 g/ml Density is > 1 g/ml

25. DO NOW: Will block Sink or float?
1.0 g/ml
Oil 0.8 g/ml

26. If I put put a penny in the column what would happen?
Substance
Density (g/cm3)
Dishwashing soap
Ethanol
0.789
Glucose syrup
Vegetable oil
Water
1.00
If I put put a penny in the column what would happen?
If I put cork in the column what would happen?