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What is Matter?. Mod.H Unit 1 L. 1. Matter is…. Anything that has mass and occupies space. ALL matter have two basic properties… Volume , and Mass. Property #1 - Volume. All matter has volume . How did we prove that air has volume?
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What is Matter? Mod.H Unit 1 L. 1
Matter is… • Anything that has mass and occupies space
ALL matter have twobasic properties… • Volume, and • Mass
Property #1 -Volume • Allmatter has volume. • How did we prove that air has volume? • Volumes of liquids are measured with what units? • Units for Volume of solids?
Volumes … • Can the volume of a gas be measured with a graduated cylinder? • So how can the volume of a gas be measured?
Find out! Write in your ntbk. What is AIR composed of? Is sound matter? What about light?
Math in Science! Complete in your ntbk. • A book has a length of 25 cm, a width of 18cm and a height of 4 cm. What is its volume? 2. a) What is the width of a suitcase with a length of 95 cm, a depth of 20 cm and a volume of 66500 cm3? b) What is the volume in m3?
Comparing liquid and solid Volumes • Remember: 1 mL = 1cm3 • Equipment: • Liquids are measured using a …? • Solids are measured using a … ? 2 Ways: • Displacement - Object itself occupies space • Capacity - Object has space within it
Property # 2 - Mass • Allmatter has mass. • Is air matter? • Do you think that air has mass? Proof?
Mass vs. Weight • Weightis NOT mass • Weight is a measure of gravitational force acting on a mass • Measured with a Spring Scale in Newtons
Gravity • Gravity is the force of attraction between objects • Gravity depends on • the amount of mass, and • the distance between masses
Newton’s Law of Universal Gravitation All objects in the universe attract each other through Gravitational pull The size of the force depends on: • The sizes(masses) of the objects, and • The distance between them.
Now, your Weight! • The Earth is very large and pulls on you. This pull decreases as you get further from the Earth. • So your weight depends on how close you are to the center of the Earth.
Comparing weights • A brick and a sponge: • Same size (volume)! • The brick weighs more because it is pulled down to Earth more (it has more mass) than the sponge • Weight decreases the further away you go from the Earth’s center
So… ! • Your weight depends on your mass PLUS how close you are to the Earth’s center. • Weight is measured in Newton's (N) or (kN - kiloNewtons) • 1 N≈Wt of a 100g
Weight is calculated by: Taking the mass of something and multiplying it by the gravity of the planet (9.8 or ≈ 10 m/s2) called acceleration due to gravity (g). Weight(Force) = mass x gravity W = mg (units=gm /s2) or F(weight) = m•a
Calculate! • What is the weight in newtons, of a set of text books that have a total mass of 3kg? • Convert to g • 3kg x 1000g/1kg = 3000 g • Then, Convert to N • 3000g x 1N/100g = 30N The book weighs ≈30N • F(w) = 30 kg • 9.8 m/s2 = 294 N
NOTE!! • The greater the mass of an object, the greater the gravitational force on the object and the greater the weight will be. • Mass stays the same for an object even when increased or decreased gravitational forces change the weight of the object.
Weight on the moon…. The moon is ≈1/6 the size of the Earth On the moon, an object weighs ≈1/6its weight on the Earth 72 N on earth = ? On the moon 72 N x 1 = 12 N on the moon 1 6 If mass = 50kg on earth = ? On moon Stays the same! = 50kg on moon
Density • Is a measure of amount of mass per unit volume • Is the same for a given substance no matter how much you have • Density = Mass Volume • D = M / V • Units: g/cm3 g/mL
Water has a density of ≈1 g/mL. • Thus, objects with density greater than 1 g/mL sink in water. • Objects with density less than 1 g/mL float in water.
HMWK: Math in Science 2 Find the following: • Mass and weight of object on the Moon, if on Earth a) its mass = 156 g, b) its weight = 204N, • Weight of object on the Earth if on the moon it weighs: a) 33 N
Answers 1 a) 156g .Mass doesn’t change! b) 204N x 1/6 = 34 N 2. a) 33N x 6 = 198 N
Mass is a measure of Inertia • Think “teenagers”!!!! • When something is at rest, it tends to stay at rest! • The larger the mass, the more inertia the matter has
Inertia is … • The tendency of an object to resist any change in motion. • The larger the mass, the harder it is to start a stationary object, or stop a moving object
HMWK • Guided Practice: Write a paragraph or make a small Graphic explaining : • How the weight of an object can change even though its mass does not change.
HMWK - in your Ntbk • Answer these questions: 1. What are the two basic properties of ALL matter? • How is volume measured? How is mass measured? • Analyze. Do objects with large masses have large weights? Explain your reasoning.