Ball and Cup Contest
Activity Objective:
Students will construct a
traditional toy and determine how
Newton’s Laws and gravity apply
to the operation of the toy.
What is Microgravity?
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This is a term NASA uses to describe
the almost weightless condition in the
in-orbit environment.
Have you ever played with a
ball and cup?
What techniques did you use
to capture the ball?
Activity
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Materials: ruler, paper cup, wooden
stick, string, and a ping pong ball
Work in groups of 2
Complete Activity sheet 6
Questions 1-4 (do not go on to
question 5 until instructed)
How does gravity affect the
ball and cup?
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Gravity pulls the ball down into
the cup and keeps the ball
from bouncing out of the cup.
How do Newton’s Laws Explain
the Movement of the Ball?
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As you swing the ball around on the string,
the string pulls inward on the ball.
According to Newton’s first law, the ball would
continue in a straight path if a force is not
acting on it.
According to Newton’s second law, an object
moves in the direction of the force that it
experiences.
The ball moves in the direction that the string
pulls on it. (results in a circular motion)
Circular Motion and
Newton’s 3rd Law
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An inward force is required to continually
turn an object from its straight-line path.
Any inward-acting force is call
Centripetal Force.
In this activity, the string pulling inward
on the ball provides the centripetal force.
According to Newton’s 3rd Law, there is
an equal and opposite reaction (force of
the ball pulling back on the string)
Gravity and Space
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Gravity also plays a role in the ball and cup
toy.
As the ball reaches the peak of the toss, it
begins to free fall and is caught in the cup,
where gravity holds it.
The cup applies an equal and opposite
(upward) force to the ball, which is countered
by gravity on Earth (Newton’s 3rd Law)
In space, the ball would strike the bottom of
the cup and bounce out again. Newton’s 3rd
Law predicts this (there is an equal and
opposite reaction force)