Grade 8 Science: Fluids & Viscosity PDF

GRADE 8 SCIENCE UNIT 3: FLUIDS & VISCOSITY Chapter 8: Density describes the amount of mass in a given volume of a substance. DENSITY 🞆A measure of the mass contained in a given volume. 🞆A substance with a lower density will float on substan...

GRADE 8 SCIENCE UNIT 3: FLUIDS & VISCOSITY Chapter 8: Density describes the amount of mass in a given volume of a substance. DENSITY 🞆A measure of the mass contained in a given volume. 🞆A substance with a lower density will float on substances with higher densities. DENSITY AND THE PTM 🞆The PTM states that different substances have different sized particles. 🞆The PTM also states that there are spaces between the particles. 🞆The greater the spaces between the particles, the less particles therefore the lower the density. Ex. Water vapour has a lower density than liquid water. 🞆In general, gases are less dense than liquids and liquids are less dense than solids. CALCULATING DENSITY 🞆Youmust know the mass and volume of a substance first. Mass: the amount of matter in a substance. Volume: the amount of space occupied by the substance. To measure the volume of an irregular shape, you will need to determine the amount of water it displaces.  Formula: Density = Mass (m) Volume (V) m D V SAMPLE PROBLEMS 1. Find the density of a 10g mass of a substance that has a volume of 2.0 cm³.  SAMPLE PROBLEMS 1. Find the density of a 10g mass of a substance that has a volume of 2.0 cm³. D=m D=10g V 2.0cm³ D=? m = 10g D=5.0g/cm³ V = 2.0g/cm³ The density of the substance is 5.0g/cm³ 2. You want to put 10g of salt into a container. What is the volume of the container if the salt completely fills it? 2. You want to put 10g of salt into a container. What is the volume of the container if the salt completely fills it? V= m V= 10g D 2.16g/cm³ V=? M = 10g D = 2.16g/cm³ (from textbook) V= 4.63cm³ The volume of the container is 4.63cm³ What is the mass of 1500mL of helium? What is the mass of 1500mL of helium? m= D x V m=? D = 0.0002g/mL (textbook) V = 1500mL m= 0.0002g/mL x 1500mL m= 0.3g The mass is 0.3g. Density Assignment! Density Lab!  TEMPERATURE & DENSITY Increasing temperature will cause the particles in a substance in gain energy, spread out and take up less space. Results in decreased density.  EXAMPLES/ APPLICATIONS... 🞆Hot air balloons 🞆Warm vs. cool tire pressure 🞆Water in each of its three states (water as a solid is less dense as the particles move apart as they freeze) 🞆Drying wood 🞆Salt water is more dense 🞆Swim bladder (fish) 🞆Submarines