SC.5.P.8.1 Lesson 1: What is Matter?

SC.5.P.8.1: Compare and contrast the basic properties of solids, liquids, and gases, such as mass, volume, color, texture, and temperature.

What is Matter?

When you walk into a room, your feet step across the floor. Does the floor change shape when you step on it? It does not: the floor is a solid. When you sit in your chair, does the chair change shape? It does not: the chair is also a solid. Solids are objects, made of matter, that don’t change shape as the result of a change in position or container. A piece of paper is a solid: if you put the piece of paper on your desk, it doesn’t change shape. When you pick it up, it might bend, but when you put it back down, it still has the same shape. These are all properties of solids.

An ice cube is a solid. It is solid water. When you take an ice cube out of the freezer, it doesn’t change shape when you put it in your cup. You could put the ice cube on your desk, and its shape will stay the same. Solids do not change shape based on changes in their containers.

When the ice cube starts to melt, it will turn into a liquid. The ice cube will drip liquid water, which will start to make a small puddle on your desk. It is easy to change the shape of the puddle with your finger. Your finger will easily slide through the liquid water as it changes shape. It you put the ice cube back into a cup to melt, the melted water will take the shape of the cup. When you pour the water from one cup into another cup, it will move and flow and take the shape of the new cup. This is a property of liquids: they can move and flow and take the shape of their container.

When you walked into the room, did you feel the air in the room on your skin? Maybe you waved hello to a friend and felt the air on your hand. Air is a gas. Like liquids, gases will move and flow to take the shape of the container. Gases are different from liquids in a very important way. Gases will fill all the space they are in. The air in the room doesn’t puddle on the floor like liquid water would. Air expands to fill the entire space it is in. If there is an opening, the gas will even expand to spread outside the container.

Water left in the bottom of a cup will begin to evaporate or change to a gas. As liquid water becomes water vapor, it will expand to fill the container. If there is no top on the container, it will expand outside the container.

What are the Properties of Gasses?

All objects and materials are matter. Matter is anything that has volume (takes up space) and mass (weight). All matter us made up of smaller particles, or pieces, called atoms. Some atoms combine with other atoms to form larger particles called molecules. For example, one molecule of water is made up of one oxygen atom and two hydrogen atoms. Water vapor, or water in its gas form, is made up of individual molecules of water that float in the air. Air in the atmosphere is made up of a mix of gasses such as nitrogen, oxygen, carbon dioxide, and other gasses, including water vapor.

Gasses are materials that take up space (volume) and have mass, or weight. This can be demonstrated with two balloons and a pan balance. When two empty balloons are placed on the pan balance, they weigh the same. When one of the balloons is filled with air, we can observe that air takes up space: it is filling the inside of the balloon and taking up that space. If we leave the balloon open, the air inside will squeeze back out through the opening and the balloon will deflate. This demonstration shows that air, a gas, takes up space.

When the balloon is filled a second time and then tied closed, the gas inside has no place to go. If the filled balloon is placed back on the pan balance with an empty balloon, we will observe that the scale is now out of balance: the filled balloon is heavier than the empty balloon. Why is the filled balloon heavier than the empty balloon?

Air inside the balloon takes up space. Air is a gas. It has volume: it takes up space. It also has mass, or weight. When the filled balloon is placed on the pan balance with an empty balloon, we observe that the filled balloon is heavier. We can conclude, based on this observation that air, a gas, has mass.

All objects and materials are made of matter. All matter, whether a single atom or a block of stone, has mass and takes up space. This is a property of all matter. Solids take up space, but don’t change their shape when moved from one container or location to another. Liquids take up spaces, but they will move and flow and change their shape when they change container. Gasses take up space, but they will expand to fill the space they are in, and, as we saw in the balloon demonstration, will expand outside their container if it is open.

Measuring Mass and Volume

All matter has mass (weight) and volume (takes up space). Matter can be solid, liquid, or a gas. Some matter, such as water, can change back and forth between states. The mass and volume of solids and liquids can be measured and recorded. The mass and volume of gasses can also be measured and recorded, but that is not a measurement we will do in elementary science.

The mass of a solid can be measured using a digital scale. Turn the scale on, place the solid on the scale, and record the mass of the object as grams (g) or kilograms (kg). The mass of a liquid can also be measured, but it takes a couple additional steps.

Because the liquid being measured would spill all over the place if we tried to place it on the scale, we have to put the liquid in a container. For example, we have found a volume of 100 ml of water using a graduated cylinder. To find the mass of the water, we have to know the mass of the empty graduated cylinder.

First, we place the empty graduated cylinder on the scale. Find measure and record the mass of the empty cylinder as 25 g. Next, we pour the liquid into the cylinder, and find the total mass of the cylinder and the liquid inside. If we put 100 ml of water into the graduated cylinder that weighed 25 grams, the total mass of the cylinder and the water would be 125 grams. 

Now we subtract the weight of the cylinder, 25 g, from the total, 125 g, and find that the mass of the liquid alone is 100 grams. 

125 g – 25 g = 100 g

We can use a similar procedure to find the volume of a solid. If we begin with a graduated cylinder with 100 grams of water in it, we can use this to find the volume of a rock, for example. Simple add the rock to the water and record the volume of both the water and the rock. If we find a total volume of 140 ml, we can subtract the volume of the water, 100 ml, from the total volume, 140 ml, and find that the rock alone has a volume of 40 ml.

140 ml – 100 ml = 40 ml

There are other tools used to find mass, or weight. Digital scales are the easiest to use.Pan balancesare sometimes used, as arebeam scales. A bathroom scale is used to find your weight, and if you go fishing, you might use aspring scaleto find the weight of the fish you catch. We’ll look at each of these scales in other investigations. Graduated cylinders, measuring cups, and spoons are the most common tools to find the volume of solids and liquids. You may even be familiar with finding the volume of rectangular prisms from math class. All of the objects and materials take up space and weight something, and we can measure and record their volume and mass.

Temperature

Temperature is another property of matter that can be observed and measured. All measurements in scientific investigations provide empirical data. Empirical data is simply data that has been measured. Finding the mass and volume of a container of water, for example, provides empirical data about the water: its mass and volume.

Temperature is the amount of heat in an object. Heat always flows from warmer objects to cooler objects. The flow of heat can be affected by whether the object or material is a conductor or an insulator. For example, if a metal pot of water is being used to boil water, the heat from the stove is conducted through the metal pot to the water. When we pick up the pot, we don’t want heat to flow into our hands, so we use an insulated hot pad to pick up the pot. Some pots have plastic handles on them that act as insulators.

Right now, you may be sitting in a classroom in an air-conditioned school. The temperature of your classroom is probably somewhere around 74° Fahrenheit. We call this temperature, somewhere between 70° and 76°F “room temperature.” If a cup of water was left out on a table in the classroom overnight, it would have time to come to the same temperature as the air in the room: 74°F. In science, we record temperature in degrees Celsius, or °C. A room with a temperature of 74°F would have a temperature of about 26°C. Any thermometer that you will be asked to measure temperature with will have both Fahrenheit and Celsius scales.

If you add ice to the cup of water sitting on the table, what would you predict would happen to the temperature of the water? Would you predict the water temperature to rise, fall, or stay the same? This is a simple investigation you can carry out on your own at home or at school.

What would your prediction be if that same cup of room temperature water was placed outside in direct sunlight? Would the temperature increase (rise), decrease (fall), or remain the same? Again, this is an investigation that you can do at home or at school.