All objects are made of matter.

Suppose your class takes a field trip to a museum. During the course of the day you see mammoth bones, sparkling crystals, hot-air balloons, and an astronaut’s space suit. All of these things are matter. Matter is what makes up all of the objects and living organisms in the universe. As you will see, is anything that has mass and takes up space. Your body is matter. The air that you breathe and the water that you drink are also matter. Matter makes up the materials around you. Matter is made of particles called atoms, which are too small to see. You will learn more about atoms in the next section. Not everything is matter. Light and sound, for example, are not matter. Light does not take up space or have mass in the same way that a table does. Although air is made of atoms, a sound traveling through air is not.

Mass is a measure of the amount of matter. Different objects contain different amounts of matter. MATTER- is a measure of how much matter an object contains. A metal teaspoon, for example, contains more matter than a plastic teaspoon. Therefore, a metal teaspoon has a greater mass than a plastic teaspoon. An elephant has more mass than a mouse.

Measuring Mass When you measure mass, you compare the mass of the object with a standard amount, or unit, of mass. The standard unit of mass is the kilogram (kg). A large grapefruit has a mass of about one-half kilogram. Smaller masses are often measured in grams (g). There are 1000 grams in a kilogram. A penny has a mass of between two and three grams. How can you compare the masses of two objects? One way is to use a pan balance, as shown below. If two objects balance each other on a pan balance, then they contain the same amount of matter. If a basketball balances a metal block, for example, then the basketball and the block have the same mass. Beam balances work in a similar way, but instead of comparing the masses of two objects, you compare the mass of an object with a standard mass on the beam.

Measuring Weight

When you hold an object such as a backpack full of books, you feel it pulling down on your hands. This is because Earth’s gravity pulls the backpack toward the ground. Gravity is the force that pulls two masses toward each other. In this example, the two masses are Earth and the backpack. is the downward pull on an object due to gravity. If the pull of the backpack is strong, you would say that the backpack weighs a lot. We ight is measured by using a scale, such as a spring scale like the one shown on the right, that tells how hard an object is pushing or pulling on it. The standard scientific unit for weight is the newton (N). A common unit for weight is the pound (lb). Mass and weight are closely related, but they are not the same. Mass describes the amount of matter an object has, and weight describes how strongly gravity is pulling on that matter. On Earth, a one-kilogram object has a weight of 9.8 newtons (2.2 lb). When a person says that one kilogram is equal to 2.2 pounds, he or she is really saying that one kilogram has a weight of 2.2 pounds on Earth. On the Moon, however, gravity is one-sixth as strong as it is on Earth. On the Moon, the one-kilogram object would have a weight of 1.6 newtons (0.36 lb). The amount of matter in the object, or its mass, is the same on Earth as it is on the Moon, but the pull of gravity is different. Volume is a measure of the space matter occupies. Matter takes up space. A bricklayer stacks bricks on top of each other to build a wall. No two bricks can occupy the same place because the matter in each brick takes up space. The amount of space that matter in an object occupies is called the object’s The bowling ball and the basketball shown on page 10 take up approximately the same amount of space. Therefore, the two balls have about the same volume. Although the basketball is hollow, it is not empty. Air fills up the space inside the basketball. Air and other gases take up space and have volume.

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Find out more about volume.

Calculating Volume: What is the volume of a pizza box that is 8 cm high, 38 cm wide, and 38 cm long? What do you know? length = 38 cm, width = 38 cm, height = 8 cm What do you want to find out? Volume Write the formula: V = lwh Substitute into the formula: V = 38 cm p38 cm p8 cm Calculate and simplify: 11,552 cm pcm pcm = 11,552 cm3 Check that your units agree: Unit is cm3. Unit of volume is cm3. Units agree. Answer: 11,552 cm3

1. A bar of gold is 10 cm long, 5 cm wide, and 7 cm high. What is its volume?

2. What is the volume of a large block of wood that is 1 m long, 0.5 m high, and 50 cm wide? Determining Volume by Formula There are different ways to find the volume of an object. For objects that have well-defined shapes, such as a brick or a ball, you can take a few measurements of the object and calculate the volume by substituting these values into a formula. A rectangular box, for example, has a length, a width, and a height that can be measured. To find the volume of the box, multiply the three values. Vo lume = length x width x height. V= lwh If you measure the length, the width, and the height of the box in centimeters (cm), the volume has a unit of centimeters times centimeters times centimeters, or centimeters cubed (cm3). If the measurements are meters, the unit of volume is meters cubed (m3). All measurements must be in the same unit to calculate volume. Other regular solids, such as spheres and cylinders, also have formulas for calculating volumes. All formulas for volume require multiplying three dimensions. Units for volume are often expressed in terms of a length unit cubed, that is, a length to the third power. 12 Unit: Matter and EnergyAB ABChapter 1: Introduction to Matter 13 Measuring Volume by Displacement Although a box has a regular shape, a rock does not. There is no simple formula for calculating the volume of something with an irregular shape. Instead, you can make use of the fact that two objects cannot be in the same place at the same time. This method of measuring is called displacement. Add water to a graduated cylinder. Note the volume of the water by reading the water level on the cylinder. Submerge the irregular object in the water. Because the object and the water cannot share the same space, the water is displaced, or moved upward. Note the new volume of the water with the object in it. Subtract the volume of the water before you added the object from the volume of the water and the object together. The result is the volume of the object. The object displaces a volume of water equal to the volume of the object. You measure the volume of a liquid by measuring how much space it takes up in a container. The volume of a liquid usually is measured in liters (L) or milliliters (mL). One liter is equal to 1000 milliliters. Milliliters and cubic centimeters are equivalent. This can be written as 1 mL = 1 cm3. If you had a box with a volume of one cubic centimeter and you filled it with water, you would have one milliliter of water. In the first photograph, the graduated cylinder contains 50 mL of water. Placing a rock in the cylinder causes the water level to rise from 50 mL to 55 m.

End of Lesson 1

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