2. What Causes a Curveball? By Kairy Hernandez Introduction

3. Science

4. Explore More According to Bernoulli's principle where a fluid moves faster there is less pressure.On one side of the ball the air is moving faster.This means the other side has more pressure. The ball is then pushed in the direction with less pressure. The force that pushes it is the Magnus force. If it is thrown slower it will have more time to curve. If there is more rotation then there will be a greater imbalance in pressure which will make the ball move more.One reason that the curveball moves slow is Newton's third law."For every action, there is an equal and opposite reaction."(Newton) The ball is pushing the air forward but drag is pushing the ball back. this slows it down more.The Magnus effect is what makes the ball curve, it is very important. The stitches change the path of the ball because they make more streamlines where they are. These streamlines move faster. This is what causes Bernoulli's principle, which causes the ball to curve.Bernoulli's principle forceMagnus forceNewton's third (Newton)

5. Explore More This picture explains the effect of the Magnus effect on a baseball. The drag force or air resistance creates a the spin on the ball which causes it to curve. Without it the ball would not curve.

6. In this picture it shows a ball with spin and a ball without spin.The streamlines, or fluid flowing steadily, are shown as the lines going towards the ball. The ball with spin is a curveball. The Magnus force is a cross product of angular velocity and tangential velocity.When throwing a curveball, angular or rotational velocity is indirectly proportional to tangential velocity. The slower or with more rotation there will be a bigger curve.The direction this force is in is the way the ball will curve. It pushes the air around the ball. This makes the air move faster on the side of the Magnus force

8. Vocabulary Force -any influence that tends to accelerate an object: a push or a pull Mass- the amount of matter in an object: a measure of an object ’ s inertia Newton’s 3rd law-."For every action, there is an equal and opposite reaction.” Newton- Discovered all of Newton ’ s Laws Also discovered Magnus Effect but never carried through Bernoulli- determined speed of fluid is increased and pressure decreases Weight- the force of a body due to the gravitational attraction of another body Graph

9. When interviewing 20 adults,I asked them if they knew what causes a curve ball. Most did not know the answer. Related Links

10. Thinkquest-Thinkquest- Shows and explains the physics principles for a curving ball. The Physics Behind Baseball-The Physics Behind Baseball- Explains why a ball curves. It also includes great demonstrations. School of Physics and Astronomy-School of Physics and Astronomy- It fully explains the effects of the Bernoulli's Principal Magnus Force-Magnus Force- This site explains what the Magnus force has to do with the curve of a baseball.