# Unit F: Energy and Change

## How does a soccer player kick the ball to make it move in different ways?

### 1. Get Set to Explore

#### Vocabulary

• clockwise: From left to right around a circle, which is the direction that the hands on a clock face move.
• counterclockwise: From right to left around a circle, which is the opposite of the direction that the hands on a clock face move.
• direction: The path an object follows.
• energy: The ability to cause motion or other changes in matter.
• force: A push or a pull.

#### Building Background

• If possible, take students outside to practice kicking soccer balls. Encourage them to figure out how they need to kick the ball to make it go straight, curve to the right, and curve to the left. After you come inside, ask students to summarize what they learned. Record their ideas on the board.
• Review the vocabulary words and their definitions with the class. Make sure that students understand the difference between clockwise and counterclockwise motion. You can draw labeled diagrams on the board.
• Pose the Discover! question and let students refer to their own experiences to answer. Add any new ideas they have to the list that is already on the board.

### 2. Guide the Exploration

• Direct students to launch the Discover! Simulation. Go over the information about the force a player exerts when kicking a soccer ball. Also discuss how the way the ball spins can affect its motion. Encourage students to relate the idea of force and spin to their own experiences kicking soccer balls or playing other sports.
• Tell students to use the control near the bottom of the screen to position the foot to kick the soccer ball. The replay shows and explains the path the ball takes. Students will have several opportunities to make a goal, with the goalie in different positions.
• After students have had a few opportunities to try to make a goal, return to the Discover! question and to students' previous ideas about how to control a soccer ball, which are posted on the board. Let students revise the answers.
• Have students use the simulation to figure out how to make the ball go straight, curve to the right, and curve to the left, recording their ideas in a three-column chart.

### 3. Review/Assess

• Ask a volunteer to read Step 3's Wrap-up text, and direct students to look over their charts to see if they understood how to make a soccer ball move in the three different ways described. If possible, return to the playground to let students try kicking the ball in the ways described.
• Have students work in groups to answer the Extension question. Encourage students to think about how the game of soccer is played as they work on their answer. Following are some situations in which it might be useful to make a soccer ball curve:
• Passing the soccer ball downfield, around opponents.
• Fooling opponents about the direction the ball will travel.
• Fooling the goalie about where you've aimed the ball.
If time permits, present students with the following questions and activity:
• Critical Thinking Observe Watch the path a soccer ball takes from the time that it is kicked until it comes to a complete stop. Draw the path of the ball. Label the spots in the ball's path when the ball has maximum potential energy and maximum kinetic energy. Answer: The ball has maximum potential energy before it is kicked, at the top of its arc when kicked and at the top of each bounce it makes, and when it has stopped. It has maximum kinetic energy just as it is kicked and just before it bounces or lands on the ground.
• Inquiry Skill Analyze List the different forms of energy that is released when a ball is kicked. Answer: Kicking a ball releases kinetic energy, sound energy, and friction of the ball moving through the air.

### 4. Reaching All Learners

#### On Level: Logical and Visual Learners

Encourage logical learners to think about other sports in which a ball or another object is routinely sent on a straight path or a curved path, depending on how contact is made with the object. Have them list three or more such sports and write down how the principles discussed in the simulation apply. Pair these students with visual learners to make an illustrated presentation about one of the sports they discussed. The presentation should focus on different ways an object is made to move in that sport.