Density PowerPoint Notes

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Bell Ringer 10/1/10 - minutes
1.
2.
3.
4.
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6.
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12.
An object has a mass of 30 kg and a volume of 5 liters. What is its density?
An object has a volume of 11 mL and a mass of 419 g. What is its density?
A rock has a density of 20.0 g/cm3. What would the volume of 340 g of this rock be?
Watch sig figs, units, & circle answers!
A rock has a density of 20.05 g/cm3. Jesse fills a graduated cylinder to a volume of 25.0
ml. He drops a sample of the rock into the g.c. and the water level rises to 29.5 ml.
What is the mass of the sample? Show all work, round to the correct number of
significant figures, and circle your answer.
Give 3 units for volume.
Give 3 units for mass.
Give 3 units for density.
A stack of nickels has a density of 8.6 g/cm3 and a volume of 7.5 cm3. What is the mass
of the nickels?
A kiwi has a mass of 111.5 g and a density of 0.95 g/cm3. What’s it’s volume?
A 5.0 kg object has a volume of 3.0 liters. What’s its density?
An object with a density of 5.0 g/cm3 has a mass of 75.0 g. What is the object’s
volume?
A block has dimensions 5.0 cm by 3.0 cm by 2.0 cm and a mass of 75.0 g. What is it’s
density?
Today you are going to…
turn in syllabus
look over all of our ocean questions
do a couple practice problems
complete the Earth as a System Reading Guide
So you can…
better appreciate the size/scale of Earth
identify the parts of the Earth system & how they interact
convert from km to mi
You’ll know you’ve got it when you
can answer the questions on the reading guide
Bell Ringer 9/30/13
1.
2.
3.
4.
5.
1 km = _____ m
What is volume? Units?
What is mass? Units?
What is density? Units?
W5SAYWoS
Mass, Volume, and/or Density
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2.
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8.
Define mass in your own words.
Define volume in your own words.
Define density in your own words.
Fundamental or derived units?
What changes when you drink the pop out of a
can?
What changes when you crush the can?
What changes when you cut an ice cube in half?
Compare a Styrofoam peanut and a grain of sand.
Golf Ball in Graduated Cylinder
Density! What is it?
Pass Around Bottles
 Hg
& H2O
Density
Density is the ratio of an object’s mass to its volume.
 Density = mass/volume
 Units of g/ml, kg/L, g/cm3, lb/gal, lb/ft3


1 g/cm3 = 1000 kg/m3
Density

A pure substance always has about the same density, no
matter what size it is. (statue of liberty example)
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The composition was pure copper from 1793 to 1837.
From 1837 to 1857, the cent was made of bronze (95 percent copper,
and five percent tin and zinc).
From 1857, the cent was 88 percent copper and 12 percent nickel,
giving the coin a whitish appearance.
The cent was again bronze (95 percent copper, and five percent tin
and zinc) from 1864 to 1962.
(Note: In 1943, the coin's composition was changed to zinc-coated
steel. This change was only for the year 1943 and was due to the
critical use of copper for the war effort.)
In 1962, the cent's tin content, which was quite small, was removed.
That made the metal composition of the cent 95 percent copper and 5
percent zinc.
The alloy remained 95 percent copper and 5 percent zinc until 1982,
when the composition was changed to 97.5 percent zinc and 2.5
percent copper (copper-plated zinc). Cents of both compositions
appeared in that year.

A pure substance always has the same density!

The density is the same no matter how much or little of it you
have.
3
Metal
Density g/cm
Aluminum
2.7
Brass
8.4 – 8.7
Copper
8.9
Gold
19.3
Iron
7.9
Lead
11.3
Nickel
8.8
Platinum
21.4
Silver
10.5
Steel
7.5 – 8.0
Tin
7.3
Titanium
4.5
Zinc
7.1
Bell Work 9/29 – 5 min
1.
2.
3.
If you increased the mass of an object while
keeping it’s volume constant, what would happen
to it’s density?
If you increased the volume of an object while
keeping it’s mass constant, what would happen to
it’s density?
What does inverse mean?
 As
you pass around these objects, put them in
order of least to most dense.
 A.
shiniest block
 B. other silver colored block
 C. yellow block
 D. golf ball
 E. marble
 F. mouse ball
 G. gray cylinder of zinc
Density, Floating, & Sinking
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
If it’s more dense than a liquid, it’ll __________ in it.
If it’s less dense than a liquid, it’ll __________ in it.


Orbits, ping pong ball, golf ball
Something with the same density as a liquid will ______.

Cannonball in mercury
Sink n Float Stuff
 Golf
balls
 Metal sphere ball in rocks changes!
Review Anticipatory Set
 Now
we’ll calculate the density of the objects!
 For which objects did it seem extremely easy to
compare the density?
 To measure the volume of regularly shaped objects
(cubes & rectangles) we measure the sides.
 A.
shiniest cube
 B. other silver colored cube
 C. yellow cube
Bell Ringer 10/2/12
Put your homework upsidedown (facing me) on your desk.
1.
55.0 liters of a liquid has a mass of 41 kg. What is it’s density?
Would it float in water?
2.
A rock has a density of 20.0 g/cm3. What would the volume of
340 g of this rock be?
3.
What is the volume of a 2 cm x 3 cm x 5 cm rectangle?
4.
When you finish, work on the back of your density worksheet.
Today you are going to…
review density hw & finish the back
So you can…
solve density problems & complete tomorrow’s lab
recognize how problems are graded
You’ll know you’ve got it when you
can answer the questions on the back of the worksheet
3. A 58.00 mL sample of mercury has a mass of 784.74 g.
What is its density?
5. Pure gold has a density of 19.32 g/cm3. How large
would a piece of gold be if it had a mass of 318.97 g?
6. A 200 cm3 sample of silver has a density of 10.5 g/cm3.
What is it’s mass?
Like # 12: Josh notes that 40.0 cm3 of a certain metal has a
mass of 180.0 g. What would the mass of 295 cm3 be?
Object
Shiniest cube
Other cube
Yellow cube
Golf ball
Marble
Mouse ball
Zinc cylinder
Silverish wire
Mass (g)
Volume (cm3)
Density
density of gold is 19.3 g/cm3. What would
the volume of 1 oz of gold be? (1 oz = 28.3 g)
 The
 Good
tutors
 Explain
how and why, don’t just do the problem
 Ask questions to help lead to understanding
 Don’t give up!
 Good
 Ask
learners
questions when they don’t understand
 Don’t give up!
Calculating Density
 First,
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you must be able to identify your variables.
16.0 g
25 g/mL
0.56 kg/L
85 cm3
250 L
35 kg
20 mL
6.023 g/cm3
85 m3
Bell Work 9/27 – 5 minutes
1.
The sides of a rectangle measure 0.5 cm x 1.0
cm x 1.5 cm, and it has a mass of 2.25 g. What
is it’s density?
2.
Your trying to find the density of a 30.0 g
irregularly shaped object. You put some water
in a graduated cylinder and measure the water
level to be 20.0 mL. You drop the object in, and
the water level rises to 25.0 mL. What’s the
object’s density?
 Density
Triangle - Cover the letter of the variable
you want to find and you will have the formula!
 For
example, if you cover the "V", you will see the
formula for volume is mass/density.
 This can be done with any formula like this!
 25
mL (milliliters) of liquid has a mass of 50 g
(grams). What is the liquid’s density?
 25
mL (milliliters) of liquid has a mass of 50 g
(grams). What is the liquid’s density?
D = M = 50 g = 2 g/ml
V 25ml
1.
An object has a mass of 30 kg and a density of 5
g/mL. What is its volume?
1. An object has a density of 10.0 g/mL and a mass
of 419 g. What is its volume?
Bell Ringer
1.
A rock has a density of 20.05 g/cm3. Jesse fills a
graduated cylinder to a volume of 25.0 ml. He
drops a sample of the rock into the g.c. and the
water level rises to 29.5 ml. What is the mass of
the sample? Show all work, round to the correct
number of significant figures, and circle your
answer.
Archimedes' principle
 Archimedes'
principle: When a body is fully or
partly immersed in a liquid, that body
experiences an upward force (the buoyant
force) equal to the weight of the displaced
liquid. The displaced liquid is that volume of
liquid equal to the volume of the body below
the water surface.
 Density of Penny 3.11 grams [pre 1982]
 2.50 grams [post 1982]
 Density of nail = 8.04 g/ml
 Density of alcohol = 0.789 g/ml
Bell Work 10/4 – 6 minutes
(Include units & tell if each will sink or float)
1. A random solid has a mass of 24 g and a volume of 35
mL. What is its density?
2. An object has a mass of 18 kg and a volume of 3 liters.
What is its density?
3. An object has a volume of 10.0 cm3 and a mass of 73 g.
What is its density?
4. If 60 mL of liquid has a density of 0.70 g/mL, what is its
mass?
5. An object has a mass of 36 g and a density of 2.5 ml/g.
What is its volume?
Density Labs
 Show
all of your work for all 4 objects (16 pts)
 Finding
volume, equation, equation with substitution,
answer with units
4
points for behavior
 Stay
in own group
 Only take one item at a time
 Clean up
Find density of cylinder
 Show
setup/procedure for finding density
Density

Density of water (@ 4oC) = 1.000 g/ml = 1.000 kg/L

Gram was defined as “mass of 1 mL of water”
More dense than water  sinks
 Less dense than water  floats
 Same density  can be suspended anywhere in it
something with the same density as water will level out in
the middle. (show examples of each)

Mass, Volume, Density?
 1.
What changes when you drink the pop out of a
can?
 2. What changes when you crush the can?
 3. Define mass in your own words.
 4. Define volume in your own words.
 5. What has more volume, a Styrofoam peanut or a
marble?
 25
mL (milliliters) of liquid has a mass of 50 g
(grams). What is the liquid’s density?
 25
mL (milliliters) of liquid has a mass of 50 g
(grams). What is the liquid’s density?
D = M = 50 g = 2 g/ml
V 25ml
Grading of Problems
1.
2.
3.
4.
Identify variables – units are clues!
Write formula
Substitution
Circle answer with correct sig figs & units
 Density
Triangle - For whatever you're trying to
solve for, cover that letter with your finger and
you will have the formula! For example, if you
cover the "V", you will see the formula for volume
is mass/density.

(review how to find it)
Density Problems (Include units, correct # of sig figs, & tell if
each will sink or float in water)
1.
A random solid has a mass of 24.0 g and a
volume of 35 cm3. What is its density?
2.
A liquid has a mass of 18 kg and a volume of
3.00 liters. What is its density?
Density Problems (Include units, correct # of sig figs, & tell if
each will sink or float in water)
3.
A liquid has a volume of 10.0 mL and a mass of
7.30 g. What would the mass of 97 mL of the
liquid be?
Bell Work 10/5
1.
Sam measures the mass of a metal ball on a
balance and it reads 50.56 g. She drops the metal
ball into a graduated cylinder and the water level
goes from 25.5 mL to 28.8 mL. What would the
volume of a of 5.5 kg metal ball be?
Density Problems (Include units, correct # of sig figs, & tell if
each will sink or float in water)
4.
If 60 mL of liquid has a density of 0.70 g/mL,
what is its mass?
5.
An object has a mass of 36 g and a density of 2.8
ml/g. What is its volume?
Density Lab Problem
Dan masses a metal cylinder and the balance
reads 22.35 g. He drops it into a graduated
cylinder with some water in it, and the water level
goes from 34.5 mL to 39.0 mL. What is the
density of the metal cylinder?
Density Lab Problem Too
Abbey masses a wooden block and the balance
reads 22.35 g. She measures the sides & finds the
block to be 3.0 cm by 4.0 cm by 6.0 cm. What is
the density of the wooden block?
Density Problems (Include units, correct # of sig figs, & tell if
each will sink or float in water)
1. A random solid has a mass of 24.0 g and a
volume of 35 cm3. What is its density?
2. A liquid has a mass of 18 kg and a volume of
3.00 liters. What is its density?
3. A liquid has a volume of 10.0 mL and a mass of
7.30 g. What would the mass of 97 mL of the
liquid be?
4. If 60 mL of liquid has a density of 0.70 g/mL,
what is its mass?
5. An object has a mass of 36 g and a density of 2.8
ml/g. What is its volume?
Density Problems (Include units, correct # of sig figs,
& tell if each will sink or float in water)
1. A random solid has a mass of 24.0 g and a volume of 35
cm3. What is its density?
0.69 g/ cm3 Float
2. An object has a mass of 18 kg and a volume of 3.00
liters. What is its density? 6.0 g/L Sink
3. A liquid has a volume of 10.0 mL and a mass of 7.30 g. What
would the mass of 97 mL of the liquid be?
0.730 g/mL 70.8 g Float
4. If 60 mL of liquid has a density of 0.70 g/mL, what is its
mass?
4 g Float
5. An object has a mass of 36 g and a density of 2.8 ml/g.
What is its volume? 1300 mL Sink
STOP
The Saltiest Sea – The Dead Sea
Are nickels made of nickel?
Are nickels made of nickel?

The U.S. first struck 5¢ nickel coins in 1866. All nickels
from that date to the present except for the famous "war
nickels" (mid-1942 to 1945) are made of the same metal,
an alloy of 75% copper and 25% nickel. "War nickels"
were made of 35% silver, 56% copper, and 9% manganese
because nickel was needed for the war effort. These coins
are distinguished by the extra large mint mark over the
dome of Monticello. They have been worth up to 90¢ for
their silver content. In August 2009, the value of the metal
in the standard nickel was about 5 cents, due to the rising
costs of copper and nickel.
Happy Birthday Jeff!

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