Forces and Motion — Answer Key
Part A: Fix the Sentence
Each sentence has an error. Rewrite it correctly on the line.
1. Fix the sentence:
A pendulum swings in a pattern, so we can predicts where it goes next.
Corrected: A pendulum swings in a pattern, so we can predict where it goes next.
In Grade 3, the modal 'can' is always followed by the base verb 'predict', not 'predicts'.
2. Fix the sentence:
The ball roll down the ramp faster each second.
Corrected: The ball rolls down the ramp faster each second.
In Grade 3 science sentences, 'the ball' is singular, so the verb must be 'rolls' to match.
3. Fix the sentence:
The swing go back and forth in a repeating pattern.
Corrected: The swing goes back and forth in a repeating pattern.
In Grade 3 writing, 'the swing' takes the -s form 'goes' because it names one object.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. A pendulum swings in a repeating pattern that we can observe.
In Grade 3, a pendulum's motion is called a pattern because it repeats again and again.
2. A ball rolling down a ramp speeds up because of gravity pulling it.
In Grade 3 science, gravity is the pull that makes a ball on a ramp move faster as it rolls down.
3. A swing that is pushed once will slow down and finally stop.
In Grade 3, friction in the chains and air resistance take energy away, so the swing will stop.
4. If a pattern repeats, we can predict what will happen next.
Grade 3 students learn that patterns let us predict future motion, like where a pendulum will swing next.
Part C: True or False?
Read each statement. Circle True or False.
1. A pendulum in Grade 3 science moves in a repeating pattern we can predict.
True False
In Grade 3, a pendulum shows a clear pattern, so students can predict its next position.
2. A ball rolling down a steeper ramp moves slower than one on a flat ramp.
True False
In Grade 3 science, steeper ramps add more force from gravity, so the ball speeds up, not slows down.
3. A swing with no push will eventually stop because of friction and air.
True False
In Grade 3, friction in the chains and air resistance slow the swing until its motion stops.