Presentation on theme: "DENSITY REMEMBER TO USE PLUS. A measure of how closely the mass of a substance is packed in a given volume Physical property Mass per unit of volume of."— Presentation transcript:
A measure of how closely the mass of a substance is packed in a given volume Physical property Mass per unit of volume of a substance Density= mass (g) volume (cm³) WHAT IS IT?
1.A substance has a volume of 2.0 cm ₃ and a mass of 38.6 g. What is the density? 2.If 17g of brass occupy 2 cubic centimeters, what is the density? TRY THESE PROBLEMS D M V
1.A substance has a volume of 2.0 cm ₃ and a mass of 38.6 g. What is the density? D=M/V Mass=38.6g Volume= 2 cm ₃ D=38.6g/2 cm ₃ D=19.3 g/cm ₃ ANSWERS
2. If 17g of brass occupy 2 cubic centimeters, what is the density? D=M/V Mass=17g Volume=2 cm ₃ D= 17g/2cm ₃ D=8.5g/cm ₃ ANSWERS
Compare the density of a substance with the density of water (always 1) Specific gravity= density of substance density of water Example: specific gravity of steel = 7.8g/ cm₃ 1.0 g/ cm₃ = 7.8 (steel is 7.8 times more dense than water) - If the specific gravity is less than 1, the object floats! SPECIFIC GRAVITY
SubstanceDensity (g/cm₃) Acrylic1.0-1.5 Aluminum2.5-2.9 Brass8.3-8.7 Copper8.7-9.1 Oak0.5-0.9 Pine0.3-0.5 Polypropylen e (plastic) 0.8-0.97 PVC1.2-1.6 Steel7.7-8.1 Water1.0 DENSITY BLOCKS
What will happen when a raw egg is placed in regular water? What will happen when it is placed in salt water? What will happen when to a lemon and a lime if placed in water? What will happen if the rind of the lemon and lime are removed and placed in water? SO WHAT’S GOING ON?
Egg in fresh water: an object that is more dense than water will sink Egg is salt water: salt is more dense than regular water and it can hold up the egg Salt ions bind with water molecules allowing the salt water to become more dense (increasing the amount of matter per space) SO WHAT’S GOING ON?
Lemon: floats Lime: sinks Lemon without rind: still floats Lime without rind: still sinks Mass of lemon: Mass of lime: Volume of lemon: Volume of lime: LEMONS AND LIMES?