Engage: States of Matter

Look around. Are there any solids, liquids, or gases in your area? What are their characteristics? How do you know the difference between states of matter?

Copy the chart into your notebook, and fill it in with characteristics and examples of each physical state.

Explore, Part 1: Heating or Cooling

What happens when you leave chocolate in a car on a hot day?

Why does the chocolate become messy? What changes?

How could you make warm chocolate less messy?

Click on the image. Follow the directions in the light blue box located at the top of the screen to observe what happens to the chocolate.

What occurred when you added heat?

What did you observe when you pushed the “Test” button?

What occurred when you cooled the chocolate?

What did you observe when you pushed the “Test” button?

Predict what will happen with the other materials. Record your observations on Explore: Part 1. You will need to download and print this page; click on Related Items at the bottom of this page, and then select Related Documents.

Continue working through the activities and recording your observations of each material.

Explore, Part 2: Melting, Freezing, and Evaporating

Download and print Explore: Part 2 by clicking on Related Items and then Related Documents at the bottom of this page.

Click on the image. Follow the directions in the light blue box located at the top of the screen to observe what happens to the water.

What do you observe when you heat ice?

What do you observe when you cool water?

What do you observe when you heat water?

What do you observe when you cool vapor?

Explain: Molding Jewelry

Click on the animation, and copy the flow chart into your notebook. Fill it in with the terms solid, liquid, and gas.

 

What happens when heat is added to ice and then water?

What happens when vapor and then water are cooled?

What can be done with gold jewelry that is no longer worn?

Click on the image to watch the video.

How is the gold jewelry turned into a gold bar? Consider changes in states of matter and how that happens.

How is gold jewelry made?

Why are heating and cooling important to these processes?

Elaborate: Infected Ice

How else are changing states of matter important in real life? Click on the image to work through the animation.

Why were the researchers in the arctic?

Why did you need to help them collect supplies?

After working through the animation, answer and discuss the following questions.

Why must ice be melted to water if a person is thirsty in the arctic?

1.  Why couldn’t a person just eat ice?

2.  How many ways could ice be melted?

3.  Why does boiling the water kill the bacteria?

Evaluate: Heating and Cooling Matters

To retake the quiz, reload the page, and then select "no" when the "Resume Quiz" dialog box appears.

 

Teacher Notes

Engage
Students should be familiar with solids, liquids, and gases (TEKS 3.5B). Solids keep their shape and have a definite volume. Examples include books, chairs, and cups. Liquids take the shape of their container and also have a definite volume. Examples include milk, water, and juice. Gases take the shape of their container, and their volume expands to fill it. Examples include air, oxygen, and helium.

Refer to solids, liquids, and gases as states of matter or physical states to familiarize students with alternate terminology. These phrases are synonyms for solids, liquids, and gases.

Notebooks are required tools for students (TEKS 3.4A) and help them record, organize, and process their work. Students can use their notebooks as study guides, too. 

Explore
Provide students time to think and discuss the answers to the questions regarding what happens to chocolate when it gets warm and what to do to make it less messy. Some students may have prior knowledge with melted chocolate in a car on a hot day. The chocolate becomes messy because it changes from a solid to a liquid with the addition of heat.

In order to make it less messy, the chocolate could be placed in a freezer to solidify it again.

Download and print Explore: Part 1 for each student. Click on Related Items, and look under Related Documents to locate this recording sheet.

When heat was added to solid chocolate, the temperature increased, changing the chocolate to a liquid. The liquid chocolate took the shape of its container. By pushing the “Test” button, the tongs reached out and shook the container. This caused the liquid to move or slosh around the container.

When students pushed the “Cool” button, the liquid chocolate changed back to a solid. The melted chocolate took the shape of the container and the chocolate retained that shape when it solidified, so the only way for students to know a change in state occurred was to push the “Test” button again. The tongs reached out and shook the container, but this time the solid chocolate did not move like it did when it was a liquid.

Ask students to predict what they think will happen with the other materials.

Distribute Explore: Part 1 to each student. Ask students to record their observations as they work through the activities for candle wax, aluminum can, and butter.

Download and print Explore: Part 2 for each student. Click on Related Items and look under Related Documents to locate this recording sheet.

When ice is heated, it melts into water. A solid changes to a liquid when heated to a certain temperature.

When water is cooled to 0 ℃, it freezes into ice. A liquid changes to a solid when cooled to a certain temperature.

When water is heated to 100 ℃, it boils and changes into vapor. A liquid changes to a gas when heated to a certain temperature.

When vapor is cooled below 100 ℃, it condenses into water. A gas changes to a liquid when cooled to a certain temperature.

If vapor is heated above 100 ℃ in a closed system, the particles will expand enough to blow the lid off the system to release pressure.

Explain
Instruct students to click on the animation to fill in the flow chart. They will drag the state of matter words to the appropriate boxes. “Gas” belongs in the far left box, “liquid” belongs in the middle, and “solid” goes on the far right. Upon completion, students should copy the flow chart into their notebooks.

When heat is added to ice, it melts to water. When heat is added to water, it changes to water vapor at 100 ℃.

When water vapor is cooled, it condenses and changes into water. When water is cooled to 0 ℃, it changes to ice.

Gold jewelry and gold scraps can be melted into gold bars at an extremely high temperature. The melting point of gold is 1064 ℃ (as compared to 100 ℃ for water). After the gold jewelry is melted from a solid to a liquid, it can be poured into a mold and allowed to cool. Once sufficiently cool, the gold bar changes from a liquid back to a solid and can be removed from the mold.

Gold jewelry is made the same way. Gold is heated at an extremely high temperature, melted into a liquid, poured into a mold, cooled back into a solid, and extracted from the mold.

Without the use of heating and cooling, we could not repurpose unused gold or create new gold jewelry.

Elaborate
Instruct students to pay close attention to the directions. Students will use the arrow keys on the keyboard to change the direction of the van as they navigate the maze.

The researchers were in the arctic gathering information and data on arctic foxes. In order to get drinking water, they needed to melt ice. Once the ice was melted, researchers discovered bacteria in the water. To kill the bacteria, the researchers needed to boil the water.

Ice must be melted to water so that it can be heated to kill any potential bacteria; ingested ice would further lower body temperature in an environment that is already cold.

Ice could be melted by boiling if a person had a fire of some sort. Students may brainstorm as many other ideas as possible. They may want to research those ideas, so the Internet, library books, or science materials may be needed.

Most bacteria cannot withstand the high temperature associated with boiling water; therefore, they break down or die. By killing the bacteria, a person is much less likely to get sick from drinking the water.

Evaluate
The quiz has five questions. Students will have three chances to correctly answer a question before the next question is introduced. Each question provides the student with immediate feedback. Following the completion of the quiz, students may review the quiz to view correct and incorrect answers.

Answer Key
1. “Gas” belongs in the blue box farthest to the left, followed by “liquid” in the middle, and “solid” on the far right.
2. Evaporation occurs, heat is added, and a liquid changes to a gas when water boils.
3. The statement is true.
4. Melting is what occurs when a solid changes to a liquid with the addition of heat.
5. A crayon melting in a hot car is an example of a solid changing to a liquid.