8.6 Properties of Matter
Tuesday, December 1st, 2015, EQ#8 Block#4
EQ: What does the concept of density represent? Is it a direct measurement or a calculation?
It represents mass and volume. It is a calculation.
AA: A box has a mass of 10 kg. How much does it weigh on Earth where the acceleration of gravity is 9.81 m/s2?
Fg =ma
Fg = 10 x 9.81
Fg = 98.1 [N]
98.1 N
Vocabulary
Matter: the amount of mass that is in an amount of space (both needed)
Inertia: an object’s resistance to a change in motion (“how much an object doesn’t want to accelerate”)
Mass: the amount of matter in an object and the amount of inertia an object has
Weight: the force of gravity acting on an object
Volume: the amount of space an object takes up
Ratio: the amount of something compared to something else Ex. $3.00/gallon, $4/dozen
Density: the measure of the amount of mass that occupies an amount of space (mass & volume). Density measures matter.
Fluid: any liquid or gas (anything with a changeable shape)
Scales (electronic or spring): devices that measure weight
Balances: a device that measures mass
Graduated Cylinder: devices that measure volume
Trundle Wheel:a device that measures distance
Wednesday, December 2nd, 2015, EQ#9 Block#1
EQ: What are the four basic properties of matter?
Mass, weight, volume, and density
AA: Explain how the density of a golf ball is different form the density of a ping pong ball.
The golf ball is denser because there is more mass, but the volume is the same.
Thursday, December 3rd, 2015, EQ#9 Block#2
EQ: There is a rock on a mass balance. It takes 4 lemons, 6 limes, and 5 cherries to balance out the system. What is the mass of the rock?
Masses: Lemon = 150 g, Lime = 100 g, and Cherry = 20 g.
Rock = 1300 [g]
AA: Compare a bucket of water to a bucket of whip cream. Which has more: A) mass, B) weight, C) volume, and D) density?
Water has more mass, water weighs more, they have the same volume, and the water has more density.
The Four Main Properties of Matter
- Mass
Symbol = m
Unit =[kg]
- Weight
Symbol = Fg
Unit = [N]
Equation = Fg = mag
- Volume
Symbol = V
Unit = [L], [m3], [mL], [cm3]
Equations =
- A cube: V = l x w x h
- A cylinder: V = πr2h (π = 3.14)
- A sphere: V = 4/3πr3
- Density
Symbol = D
Unit = (small) g/cm3, (large) kg/m3
Equation = D = m/v
Measurement Tools:
- Distance
- Meter stick
- Ruler
- Trundle Wheel
- Odometer
- Time
- Watch or Clock
- Sun or Sun Dial
- Stopwatch
- Hourglass
- Mass
- Mass balance
- Doctors balance
- Triple beam balance
- Weight
- Spring scale
- Electronic scale
- Bathroom scale
- Volume
- Graduated cylinder
- Beaker
- Measuring cups
- Speed
- Speedometer
- Radar gun
- Acceleration
- Accelerometers
- Temperature
- Thermometer
Measuring Devices
A. Mass Balance
Steps:
1. Make sure the system is balanced
2. Put the object of unknown mass in one of the baskets
3. Put objects of known mass in the other basket, until the system is balance
4. Add up the known mass for the value of the other mass
Example:
You put a candy cane in one basket
You put green beans in the other basket until it is balanced, which was 6 green beans
Green beans mass = 2 g
6 green beans x 2 g = 12 g
Therefore, the candy cane = 12 g (m = 12g)
B. Triple Beam Balance
Steps:
1. Slide the three masses to the left (If not balanced, turn the screw to balance it)
2. Put the unknown mass on the tray
3. Move the large mass until the scale tips, then back it up one space
4. Repeat with the middle mass
5. Move the small mass until the system balances
6. Add the three masses together for the unknown mass
C. Electronic Scale
Steps:
1. Press the “on” button
2. Select the correct unit
3. Press the “tare” button
4. Put the object on the tray
5. Read the value for the object
Wednesday, December 9th, 2015, EQ #9 Block#3
EQ: What are the three different ways to measure the volume of an object?
Calculation, water displacement, and overflow can
AA: You only have a triple beam balance, a roll of masking tape, and a ball. You want to find the mass of the ball, but it keeps rolling off the balance. Write a procedure to successfully find the mass of the ball with these materials.
Roll tape to have it sticky on all sides. Place on the balance. Find the mass of the tape. Put the ball on the tape and find the mass of both. Subtract the mass of the tape.
How to Measure Volume?
Volume :the amount of space something takes up
[cm3] – used to measure volumesof solid objects
[mL]–used when finding the volumes of liquids
- 1 [cm3] = 1 [mL]
Methods for Measuring Volume:
1. We can measure volume by calculation
*Only good for perfect shapes
a)Cube – V = l x w x h
b)Sphere – V = 4/3πr3
c)Cylinder – V = πr2h
2. Water Displacement
*When an object is not a perfect shape
Steps:
1. Put water in a graduated cylinder
2. Measure the water in the cylinder
3. Submerge the object under the water
*If it floats, push the object under water
4. Measure the volume again
5. Subtract the two volumes
3. Overflow Can
1. Overfill can with water
*Allow to drain out the spout
2. Position a graduated cylinder under the spout
3. Submerge object
4. Read the volume on graduated cylinder
Ex: 63 [mL] of water, Yoda Volume = 63 [cm3]
Thursday, December 10th, 2015, EQ#9 Block#4
EQ: How can you tell if an object will sink or rise when placed in water?
If the density of an object is greater than the surrounding fluid, the object sinks
If the density of an object is less than the surrounding fluid, the object floats
If the density of an object is equal to the surrounding fluid, the object suspends
AA: Find the volume occupied by a lab station. Show your work below. Work in small groups. Do this calculation in [m3].
Example:
V = l x w x h
V = (1.65) (1.05) (.93)
V = 1.61 [m3]
What is Density?
Density: a measure of how close the particles in an object are
Equation: D = m/v
Unit: liquid = g/mL solid = g/cm3
How Density Changes
- If mass goes up, density goes up
- If mass goes down, density goes down
- If volume goes up, density goes down
- If volume goes down, density goes up
Rules of Density
1. If the density of an object is greater than the surrounding fluid, the object sinks
*Ex: people in air, rocks in a pond
2. If the density of an object is less than the surrounding fluid, the object floats
*Ex: aircraft carrier in ocean, clouds in the air
3. If the density of an object is equal to the surrounding fluid, the object suspends
The Ice Exception
1. Most objects are more dense when they are in the solid form
2. Ice is an exception to this rule
- Ice is less dense than water
3. Water floats on ice
4. The density of ice is 0.91 [g/cm3]
5. The density of water is 1.0 [g/mL]
6. 10% of ice is above the water line and 90% below