DENSITY Density and Buoyancy Key Points Density Density
DENSITY
Density and Buoyancy. Key Points Density • Density is the ratio of mass to volume • The solid state of a substance is usually denser than liquid state. The liquid state is denser than the gas state. • What is Density? Video
BUOYANCY • BUOYANCY = the ability to float in a fluid. • Examples of fluids = water, air • BUOYANT FORCE = the upward force that acts on a submerged object. – It acts opposite of gravity
Why do Boats Float? • 1 st-Boats are designed to minimize water entry • 2 nd The water density vs. the boat’s density (metal of the boat, people, etc) is less than the water Result: THE BOAT FLOATS
Mass = 90 kg A Mass = 90 kg B WHICH ONE IS MORE LIKELY TO FLOAT?
DENSITY d=m/v DENSITY OF WATER = 1 g/cm 3 • If the object has a higher density, it sinks. • If the object has a lower density, it floats. • if the object has the same density, it flinks (floats in the middle of the water).
Density and Temperature CHANGING DENSITY BY ADDING HEAT RESULT: 1. Particles move faster 2. Particles spread apart 3. Volume increases 4. Density decreases FREEZING A LIQUID RESULT: 1. Particles move slightly further apart 2. Increasing volume 3. Decreasing density
Measuring Units • Density of liquids = Grams per milliliter (g/ml) • Density of Gas = Kilograms per liter (kg/L) • Density of Solids = Grams per cubic centimeter (g/cm 3)
Calculating Density, Mass, Volume D= DENSITY M= MASS V=VOLUME Density= M V Mass= D x V Volume= M D
Sample Equation A 20 ml sample of oil has a mass of 1. 76 g. What is its density? Steps: G: V=2. 0 m. L M= 1. 76 g Given Required to find Analysis (Formula) Solution Statement R: Density=? A= D=M V S: 1. 76 2. 0 m. L = 0. 88 g/m. L S: The oil has a density of 0. 88 g/m. L
Sample Equation A liquid as a mass of 450 g and a density of 0. 90 g/ml. What is its volume? Steps: G: M=450 g D= 0. 90 g/m. L Given Required to find Analysis (Formula) Solution Statement R: V=? A= V=M D S: 450 g 0. 90 g/m. L = 500/m. L S: The volume of the liquid is 500/m. L
Homework Work on Questions 1 -5
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