Force Detectives
A student pushes a toy wagon with one hand. Is the force a touching force or a non-touching force?
Touching force
Two students push a box from opposite sides with equal strength. The box stays still. Are the forces balanced or unbalanced?
Balanced
Two magnets are placed with a north pole facing a south pole. Will they attract or repel?
Attract
A balance tilts down on the side with a heavier object. Are the forces on the two sides balanced or unbalanced?
Unbalanced
A magnetic crane holds a magnet with its south pole facing a metal cart’s magnet. Which pole of the cart’s magnet must face the crane to attract it?
A north pole facing the crane’s south pole will attract it.
A dropped leaf moves toward the ground. Which force pulls it downward?
Gravity
4th graders are playing tug of war at recess. The rope suddenly is pulled to one side, and that side won. What happened to the rope? Use the words balance or unbalanced, forces and motion in your response.
The side that won pulled the rope to the other harder and made the forces unbalanced, which caused the motion of the rope to go to one side.
A magnet picks up a metal paper clip when it is close. The washer is moved much farther away. What is likely to happen to the magnetic attraction?
The magnet will no longer attract the paperclip.
A large boulder rests on level ground and does not move. Are the forces on the boulder balanced or unbalanced?
Balanced
The crane magnet’s south pole faces the cart’s north pole. What will the cart do?
It will attract.
A students puts two magnets near each other. They begin moving by pushing away. What force makes them push away?
Repel
A very heavy brick is on the brick winner's desk. Gravity is holding it in place. What should you do if you want to move it? Include the word force, balanced or unbalanced in your response.
I need to pull the brick up to make the forces unbalanced.
Two magnets are placed with their north poles facing each other. Will they attract or repel?
Repel
Two teams pull equally hard in opposite directions during a tug of war, and the rope does not move. What does this tell you about the forces?
The forces are balanced
The crane magnet’s south pole faces the cart’s south pole. Will the cart move toward or away from the crane magnet?
It will move away because the magnets will repel.
A magnet pulled a paperclip to make it stick. Is this a touching force or a non-touching force?
Non-touching force.
A toy car is rolling straight across the floor. It bumps into a block and turns to the left. What changed: the car’s speed, direction, or both?
Both
A recycling center wants to separate steel bottle caps from paper and plastic. How could workers use a magnet to help?
Put a magnet on top to move the metals towards the magnet
A student lifts a box off the floor. What must the student’s upward force do compared with the downward pull of gravity for the box to rise?
The student’s upward force must be greater than the downward pull of gravity for the box to rise.
A metal cart blocks a narrow cave path and is difficult to reach by hand. How could a magnetic crane help move it?
The crane can use its magnet to attract and move the metal cart out of the path.
A student designed a device that made a paperclip float in the air by a magnet above it. What two forces are acting on the paperclip?
Gravity pulls it down. The magnet attracts it up.
A ball is resting on the ground. A student gives it a strong kick. Make a claim about what happens to the ball and give a reason using the words force and motion.
The ball will start moving because the kick applies a force that changes the ball’s motion.
A metal key has fallen into a narrow space where it is hard to reach by hand. How could a magnet help retrieve it?
A magnet placed near it could pull the key up
A box is pushed to the right by one student. Make a claim about whether the forces are balanced or unbalanced, and give a reason.
The forces are unbalanced because the box moves to the right, so the push to the right is greater than the push to the left.
A cart attached to a magnet moves toward a second magnet held nearby. Make a claim about whether the facing poles attract or repel, and explain how the cart’s motion supports your claim.
The facing poles attract because the cart moved toward the second magnet.