# How SMOOTHNESS of a SOCCER BALL affects curve! | Summary and Q&A

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May 24, 2016
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Physics Girl
How SMOOTHNESS of a SOCCER BALL affects curve!

## TL;DR

The Reverse Magnus Effect is when a spinning ball curves in the opposite direction due to differences in boundary layers.

## Key Insights

• ⚽ The Magnus Effect, also known as curving or bending the ball, is a well-known phenomenon in sports.
• 💬 The Reverse Magnus Effect occurs when the ball curves in the opposite direction due to changes in the boundary layers of turbulent and laminar flow.
• 💐 The transition between turbulent and laminar flow in the boundary layers is crucial for understanding the Reverse Magnus Effect.
• 🥺 The sensitivity of the boundary layer transition can lead to unexpected changes in the ball's flight path.
• 🤕 Small modifications, such as roughness on the ball or the addition of a rubber band, can reverse the direction of the Magnus Effect.
• ⚽ The Reverse Magnus Effect has been observed in various sports where spinning balls are involved.
• ❓ The Reverse Magnus Effect demonstrates the intricacies of fluid dynamics and the impact of airflow on object trajectories.

## Transcript

NARRATOR: You've all seen the shot. Kick the ball with some spin, and it'll curve, if you're lucky, right into the goal. This is known as curving the ball, or bending the ball, or if you're from the 19th century, as a screwball. And in fluid dynamics, it's known as the magnus effect. And supposedly the magnus effect can be reversed. That is, kick t... Read More

### Q: What is the Magnus Effect?

The Magnus Effect is the curving or bending of a spinning ball in a given direction due to differences in air flow caused by the spin.

### Q: What causes the Reverse Magnus Effect?

The Reverse Magnus Effect occurs when the boundary layers of turbulent and laminar flow switch, causing the airflow to deflect in the opposite direction, resulting in a curve in the opposite direction.

### Q: How sensitive is the boundary layer transition for the Reverse Magnus Effect?

The boundary layer transition from turbulent to laminar flow is highly sensitive, and even small changes, such as roughness on the ball or the addition of a rubber band can affect the direction of the curve.

### Q: Can the Reverse Magnus Effect be observed in other sports?

While the Reverse Magnus Effect is commonly observed in soccer, it can also occur in other sports involving spinning balls, such as tennis, baseball, or golf.

## Summary & Key Takeaways

• The Magnus Effect, also known as curving or bending the ball, occurs when a spin is applied to a ball, causing it to curve in one direction.

• The Reverse Magnus Effect flips the direction of the curve because of changes in the boundary layers of turbulent and laminar flow.

• The transition between turbulent and laminar flow in the boundary layers of the ball affects the direction of the curve, and even slight changes can alter the ball's flight.