2 Matter…Makes up all of the objects and living organisms in the universeAnything that has mass AND takes up spaceLight and sound are NOT matter…why?Matter is made of particles called atoms…matter IS atoms.Atoms have massAir is made of atomsSound and light waves traveling through air do not have mass OR take up space
3 Three (of five) forms of Matter: Solid matter - has a fixed volume and shape of the object or substance.Liquid matter - has a definite volume but not a definite shape.Gas matter - does not have a definite shape and volume.
4 Mass… A physical property of matter Measure of how much matter an object containsStandard unit: Kilogram (kg)1 kg = 1000 grams (g)Ex: grapefruit: 500 g, penny: 2-3 gMeasure mass using a triple-beam balancecomparing a known amount of matter (standard mass) to an unknown amount of matter (measured mass)
5 Mass vs WeightMass is a measurement of the amount of matter something containsWeight is the measurement of the pull of gravity on an object.Mass is measured by using a balance comparing a known amount of matter to an unknown amount of matter.Weight is measured on a scale.The Mass of an object doesn't change when an object's location changes.Weight does change with location.
6 A triple beam balance compares a known mass to an unknown mass, so it is unaffected by gravity. A scale measures weight, the triple beam balance gives a true measure of mass.On the moon the mass on the left side of the balance may 'exert less force', but then less force will be needed to balance it.
7 Weight and Gravity Recall… Gravity is the force that pulls two masses toward each otherStandard unit: Newton (N)Common unit: Pound (lb)Force = mass * acceleration (F=ma)Newton = kilogram*meter/second^2 (N = kg m/s2)Weight is a force!Mass is amount of matter of an object, weight is how strongly gravity is pulling on that matter
8 F = G[M m/r2]What will cause the force of attraction to increase or decrease?If either mass increases the force of attraction increases proportionally. Since the moon has 1/6 the mass of earth, it would exert a force on an object that is 1/6 that on earth.Why is the 1/r2 factor so important?This is an inverse square relationship which seems to show up a lot in physics. How does it affect the force?When r=1 the value 1/r 2 is 1.0, but at r=10 it deceases to 1/100. That means gravity gets weak 'quick' as we move away from the earth.
9 Compute Mass and Weight If a cube has a mass of kilograms and a weight of 200 pounds on Earth, what will its mass and weight be on another planet?The Moon has a gravity that is of Earth's.The cube will have a weight of________________ poundsand a mass of_______________ kilogramsJupiter has a gravity that is 2.34 times greater than Earth's…weight? Mass?
10 Compute Mass and Weight On the moon:Weight = 33 lbMass = still kg!On JupiterWeight = 468 lbMass = kg
11 Volume Volume is the amount of space an object occupies. The volume of an object can be calculated geometrically using mathematical equations or by measuring liquid displacement.Measure the volume of a cube using the formula V=(side)x(side)x(side) (length times width times height) and by using a graduated cylinder to measure liquid displacement.
12 Volume = L x W x H (cm3 or in3 etc.) 1.22 in V = 1.82 in33.1 cm V=29.8 cm3Volume = L x W x H (cm3 or in3 etc.)The side of the cube is approximately 3.1 centimeters. How many inches does this convert to (use 2.54 cm. = 1 inch)?
13 Measure Volume by Displacement What was the amount of water displaced by the object? (1 ml = 1cm3) Before After
14 Density Each box has the same volume. If each ball has the same mass, which box would weigh more? Why?
15 DensityThe box that has more balls has more mass per unit of volume. D = m/VThe density of a material helps to distinguish it from other materials.Mass: grams (g) or kilograms (kg)Volume: cubic centimeters (cm3) or cubic meters (m3)Density: grams/cubic centimeter (g/cm3) or kilograms/cubic meter (kg/m3)1000g = 1 kgcm3 = 1 m3.001g/cm3 = 1 kg/m3Periodic Table masses:One gram is about 600,000,000,000,000,000,000,000 amu (a 6 followed by 23 zeros) = 6 x 1023 amu.
16 Density of a LiquidProblem: You are given two unknown liquids. Find the density of each. Materials: 100ml graduated cylinder, triple beam balance, calculator, 2 unknown liquids.Procedure:1) Find the mass of the empty graduated cylinder.2) Pour unknown liquid #1 into the graduated cylinder to the 50 ml. level.3) Find the mass of the graduated cylinder with 50ml of unknown liquid #1.4) Repeat steps 1-3 for unknown liquid #2.
17 Density of a Liquid Liquid #1: Given: Mass of empty graduated cylinder = 78 gramsMass of graduated cylinder with unknown liquid #1= 128 grams.Find:a) Mass of just the liquid = ____ b) Volume of liquid=_____ c) Density of liquid #1 =____Liquid #2:Given: Mass of empty graduated cylinder = 78 gramsMass of graduated cylinder with unknown liquid #2= grams.Find:a) Mass of just the liquid = ____ b) Volume of liquid =_____ c) Density of liquid #2=____1 g/mL g/mL
18 What is the Liquid?SubstanceDensity (gm/cu.cm)Water1.00Cooking oil0.92Sea Water1.025Carbon tetrachloride1.58Benzene0.87Glycerin1.26Methanol0.79What is each liquid? Using the table below it is now possible for you to determine what each liquid is.Densities for some common liquids are:
20 Extension: Air Pressure Air pressure is the force exerted by the weight of a column of air above a particular location.Imagine a sealed container full of air
21 Change the pressureIncrease the density of the air by either putting more air molecules into the container or reducing the volume of the container.Therefore, changes in air pressure can come about by changes in air density
22 Atmospheric pressure is defined as the force per unit area exerted against a surface by the weight of the air above that surface.If the number of air molecules above a surface increases, there are more molecules to exert a force on that surface and consequently, the pressure increases.The opposite is also true, where a reduction in the number of air molecules above a surface will result in a decrease in pressure.
23 Air Pressure & Altitude Air pressure decreases as one moves upward through the atmosphere because the length of the column of air shortens and hence there is less mass above a given location.Because air is highly compressible, the air is closely packed together near the surface (high density) and less densely packed aloft