SCIENCE SKILLS 2.1 Chapter Two: Science Skills 2.1 Mass and Volume 2.2 Density 2.3 Graphing 2.4 Solving Problems Section 2.1 Learning Goals Explain the meaning of mass and describe the units for measuring mass. Distinguish between mass and weight. Define volume and explain how the volume of matter is measured. Investigation 2A Measuring Mass and Volume Key Question: How do you measure mass and volume? 2.1 Measuring mass Mass describes the amount of matter in an object. The SI unit for mass is the kilogram (kg). The kilogram is too large a unit to be convenient for small masses. One gram (g) is one-thousandth of a kilogram. What is the estimated mass of ONE zinc nut? 2.1 Matter Matter is anything that has mass and takes up space. All matter has mass. Steel, plastic, rubber, and glass are different kinds of matter. A car has a lot more of each kind of matter than a bike. 2.1 Mass and weight are different We tend to use the terms mass and weight interchangeably, but they are not the same thing. Mass is the amount of matter in an object. Weight is a measure of the pulling force of gravity on an object. 2.1 Mass and weight are different A 2.3 kg bag of flour has a mass of 2.3 kilograms no matter where it is in the universe. The weight of the bag of flour is less on the moon. The 5 lb bag of flour on Earth weighs only .8 lbs on the moon! 2.1 Volume Volume is the amount of space an object takes up. The fundamental unit of volume in SI is the cubic meter (m3). More convenient smaller units are cubic centimeters (cc or cm3), liters (L) and milliliters (mL). 2.1 Volume Measuring the volume of liquids is easy. Pour the liquid into a graduated cylinder and read the meniscus at eye level. 2.1 Displacement You can find the volume of an irregular shape using a technique called displacement. Put the irregularly shaped object in water and measuring the amount of water displaced. 2.1 Comparing mass and volume Mass and volume are two different properties of matter. Size does not always indicate an object’s mass! How the matter is packed into space is more important.