Curve Of A Soccer Ball

This lesson introduces students to the concept of curving a soccer ball. Begin with a brief discussion to gauge their knowledge. Explain the technique using examples from famous players, then introduce the Magnus effect, which explains how a spinning ball curves due to differences in air pressure. Use simple diagrams to illustrate this. Finally, take students outside to practice different types of kicks, allowing them to observe and experiment with curving the ball. Conclude with a reflection on their experiences.

Objectives

Students will explore the physics behind how and why a soccer ball curves when kicked and attempt to curve a kicked soccer ball.

Materials

  • Worksheet
  • Soccer ball
  • Beach ball
  • Soccer goal or target
Curve Of A Soccer Ball

Academic Standards

6th Grade

Math 6.4.H The student is expected to convert units within a measurement system, including the use of proportions and unit rates.

PE 6.3.E The student is expected to demonstrate correct technique in kicking and punting with accuracy during dynamic activities and lead-up games.

7th Grade

Math 7.4.B The student is expected to calculate unit rates from rates in mathematical and real-world problems.

PE 7.3.E The student is expected to apply correct technique in kicking and punting with control, distance, and accuracy during game situations and sports.

8th Grade

Math 8.2.B The student is expected to approximate the value of an irrational number, including π and square roots of numbers less than 225, and locate that rational number approximation on a number line.

PE 7.3.E The student is expected to apply correct technique in kicking and punting during game situations and sports with control, distance, and accuracy.

Curve Of A Soccer Ball

Discussion Questions

  • What does it mean to curve a kick in soccer?
  • Why might a player want to curve the ball instead of kicking it straight?
  • How do you think the curve affects the goalkeeper’s ability to stop the ball?
  • What other techniques do you know of that are often used in soccer?

Reflection Questions

  • What did you notice about how different types of spin affect the curve of the soccer ball?
  • Why do you think it’s important for athletes to understand the science behind their sports?

Answer Key

  1. As the ball rotates, friction drags a layer of air around with it. This makes the air move faster on one side (where the spin and airflow go the same way) and slower on the opposite side (where they oppose each other).
  2. It offers the largest surface area for a clean contact and helps create a side spin by hitting the ball off-center instead of hitting it dead center.
  3. It creates an outward spin, forcing the ball to curve away from your kicking side.
  4. When you strike the ball on the side with your foot angled across the ball, what happens to the ball’s path?
  5. Spin is the most direct factor that bends the ball’s flight path. However, speed and angle work together with spin to control exactly how much it would curve.
Curve Of A Soccer Ball
Curve Of A Soccer Ball

Setup

  • Set up cones or markers to designate a target area where students will aim their kicks. This requires an outdoor space where students have enough room to kick a ball with force.

Vocabulary

Magnus Effect: A physical phenomenon characterized by the generation of a sidewise force on a spinning object moving through a fluid.

Curve Of A Soccer Ball

Activity

  • Start the lesson by leading students in a short discussion to assess what they already know about bending a soccer ball.
    • Use the questions provided as a jumping-off point, or come up with your own.
  • Explain curving in soccer:
    • Start by discussing how some of the most famous soccer players, like David Beckham or Cristiano Ronaldo, are known for their ability to curve the ball when taking free kicks.
    • Show the video clip of a curving free kick to capture students’ attention and set the context for the lesson.
  • Briefly explain the science behind the curve. Choose how much in detail you want to go with this topic.
    • Introduce the concept of the Magnus effect, explaining that when a soccer ball is kicked with a spin, the air pressure on one side of the ball becomes lower, causing the ball to curve.
    • Use simple diagrams on the whiteboard to illustrate how the spinning motion of the ball creates differences in air pressure, leading to a curved trajectory.
  • Show students the video below on how to curve a kick. Have students share what they noticed after watching the video.
  • Curved kicks activity
    • Take the class outside to a field or gymnasium. Set up cones or markers to designate a target area where students will aim their kicks.
    • Divide students into small groups, and provide each group with a soccer ball.
      • You can start by having students practice with a beach ball, then move to a soccer ball once they feel comfortable.
    • Challenge the students to kick the ball in different ways.
      • Kicking straight with no spin.
      • Kicking with side spin (inside or outside of the foot).
      • Kicking with backspin or topspin.
    • Have students record their attempt observations.
  • Lead students in a short reflection at the end of the activity using the questions provided or your own.

Additional Activity

  • Put up a video of penalty shootouts in a soccer game. Pause right before the striker kicks the ball and ask students to predict the path the ball will take based on the foot placement and any previous knowledge they have of the player. Compare the number of curved kicks amongst all penalties taken - do all players attempt it?
Curve Of A Soccer Ball