Grade 8 Science Chapter 8 Notes PDF

Grade 8 Science Chapter 8 Notes Mass 🡪 the amount of matter an object has. - does not mean weight - the unit for mass is grams (g) How do we determine mass? Solid - put the solid on a balance and record the mass Liquid - put an empty beaker on the balance and p...

Grade 8 Science Chapter 8 Notes Mass 🡪 the amount of matter an object has. - does not mean weight - the unit for mass is grams (g) How do we determine mass? Solid - put the solid on a balance and record the mass Liquid - put an empty beaker on the balance and press the “Tare” or “Zero” button. Remove the beaker, add the liquid and put the beaker back on the balance to record the mass. Volume 🡪 the amount of space taken up by an object or substance. - the unit for volume is mL (liquid) or cm3 (solid) How do we determine volume? Solid - use the displacement method Liquid - read the liquid level from the side of the beaker Displacement method - Put water in a graduated cylinder. Record the water leve. Put the solid in and record the water level again. The difference in water level is equal to the volume of the solid. Density 🡪 the amount of mass in a certain volume; how tightly packed together the material in a substance is. Ex: Oil will float on water because it is less dense. - The unit for density is g/mL or g/cm3 Question: How does temperature effect density? Ans: As you increase the temperature of a substance the particles move faster and farther apart. With more space between the particles, the volume of the substance increases but the mass still stays the same. This decreases the overall density. Ex: Hot air balloon - as you head the air, the particles move farther apart decreasing the density. This causes the air to rise taking the balloon with it. Calculating Density Density = Mass Volume M Volume = Mass Density D V Mass = Density x Volume Force - anything that causes a change in the motion of an object - the unit for force is Newtons (N) Balanced force - when opposite forces are equal. There is no change in the motion. Ex: your chair is putting an upward force on you equal to the downward force you are putting on it. This is why you do not break through your chair. Unbalanced force - when opposite forces are unequal. There is a change in the motion. Ex: if the upward force of the chair is not equal to the downward force then you will break your chair. Buoyancy - the upward force exerted on objects that are floating or submerged in a fluid. Pressure - force acting on an area. Measured in Pa (N/m2) Calculating Pressure: Use the Formula triangle to help determine your formulas: Pressure = Force Area F Area = Force Pressure P A Force = Pressure x Area