Transcript PowerPoint - Shorecrest Preparatory School

What Causes a
Curveball?
By
Kairy Hernandez
Introduction
Introduction
Science
Science
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.
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.
Explore More
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
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
What Causes a Curveball?
12
11
Number of Responses
10
8
6
5
4
4
2
0
Don't Know
Incorrect
Correct
Adult Responses
When interviewing 20 adults,I asked them if they
knew what causes a curve ball. Most did not know
the answer.
Related Links
Thinkquest- Shows and explains the physics
principles for a curving ball.
The Physics Behind Baseball- Explains why a ball
curves. It also includes great demonstrations.
School of Physics and Astronomy- It fully explains the
effects of the Bernoulli's Principal
Magnus Force- This site explains what the Magnus
force has to do with the curve of a baseball.