Transcript Calculating Density - Powers Physical Science

Calculating Density
1. What is Density?
a. What is the same about these objects?
1a. What is the same about these objects?
Answer:
These soda
bottles all have
the
same volume.
1. What is Density?
b. What is different about these objects?
1b. What is different about these objects?
Answer:
These soda bottles
contain different
samples of matter
(cotton balls, water,
iron filings, and air.)
1c. What is Density?
Density is the amount of mass
(or matter) per volume.
2. Which of the bottles is the MOST DENSE?
2. Which of the bottles is the MOST DENSE?
Answer:
The soda bottle
full of iron filings
is the MOST DENSE.
2. Which of the bottles is the LEAST DENSE?
Answer:
The soda bottle
full of air is the
LEAST DENSE.
3. How is DENSITY calculated?
We use the formula:
Density = mass/Volume
4. The DENSITY formula can be
remembered using this trick:
Draw a T-Triangle on
your paper:
4. The DENSITY formula can be
remembered using this trick:
Inside the T-Triangle add the three
letters from the Density formula.
D = m/V
m
Think:
D
but put a D in place of the T.
V
5. Using the DENSITY T-Triangle
Cover the D on the
Density T-Triangle.
m
What is left is the formula
for Density!
D = m/V
D
V
5. Using the DENSITY T-Triangle
Cover the m on the
Density T-Triangle.
m
What is left is the
formula for mass!
m = DV
D
V
5. Using the DENSITY T-Triangle
Cover the V on the
Density T-Triangle.
m
What is left is the
formula for Volume!
V = m/D
D
V
6. Let’s solve a problem using the
DENSITY T-Triangle!
Example #1.
What is the density of an object with a mass of 50
g and a volume of 100 cm3?
m
What is the formula
for Density?
D
V
6. Here’s how you solve the problem.
Example #1.
What is the density of an object with a mass of
50 g and a volume of 100 cm3?
Formula
(1) D = m/V
Substitute
(2) D = 50 g / 100 cm3
Solve
(3) D = 0.5 g/cm3
7. Let’s solve another problem
using the DENSITY T-Triangle!
Example #2.
What is the mass of an object with a density of
1.2 g/mL and a volume of 0.3 mL?
m
What is the formula
for mass?
D
V
7. Here’s how you solve the problem.
Example #2.
What is the mass of an object with a density of
1.2 g/mL and a volume of 0.3 mL?
Formula
(1) m = DV
Substitute
(2) m = 1.2 g/mL X 0.3 mL
Solve
(3) m = 0.36 g
Notice: The like terms (mL) were cancelled
so only “g” was left for the answer!
8. Let’s solve another problem
using the DENSITY T-Triangle!
Example #3.
What is the volume of an object with a density
of 3 g/cm3 and a mass of 30 g?
m
What is the formula
for volume?
D
V
8. Here’s how you solve the problem.
Example #3.
What is the volume of an object with a density of
3 g/cm3 and a mass of 30 g?
Formula
(1) V = m/D
Substitute
(2) V = 30 g X 3 g/cm3
Solve
(3) V = 10 cm3
Notice: The like terms (g) were cancelled
so only “cm3” was left for the answer!
9. Important things to remember:
a. Water has a density of 1 g/mL
b. 1 gram of water has a volume of 1 mL
c. 1 g = 1 mL (Water only!)
d. cm3 and mL are the same thing
and therefore interchangeable!
10. Solve these problems.
Example #4:
What is the mass of an object with a density of
5 g/cm3 and a volume of 15 mL?
Example #5:
What is the density of an object with a mass of
300 g and a volume of 30 mL?
Example #6:
What is the volume of an object with a mass of 25 g and
a density of 5 g/mL?
When you are finished…
…turn this paper in to your teacher.
BONUS #1:
How do you know
the iron filings bottle
has more density?
HINT: What part of the Density
Formula changes from bottle to bottle?
THE END
BONUS #2:
If the feather and
the
elephant were the
same size, which one would
be less dense?
Why?