Lesson · Grade 6 · Science
Newton's First Law: Why Things Keep Moving
- Grade 6
- Science
- 1 min 11 s
- British Columbia
- BC6-SC-10
A box sits still on a floor because gravity and the floor's push are balanced. The same push then sends it a short way on the floor, much farther on ice where there is less friction, and on forever at the same speed in space. The video then gives Newton's first law: an object stays still, or keeps moving at the same speed in a straight line, unless an unbalanced force acts on it. It calls this the law of inertia, because objects resist changes to their motion.
Concept: Newton's first law: inertia
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In one sentence
The question this lesson answers
What makes things start moving, and what makes them stop?
A box sitting on the floor stays still.
Transcript
What the lesson says
What makes things start moving, and what makes them stop?
A box sitting on the floor stays still.
Gravity pulls it down and the floor pushes it up, so the forces are balanced.
A push from the side makes the forces unbalanced.
The box slides, but friction from the floor slows it to a stop.
Ice has less friction, so the same push makes the box slide much farther.
Far out in space, there is no floor and no air to slow it down.
Once it is pushed, it keeps moving at the same speed in a straight line.
This is called Newton's first law of motion.
An object stays still, or keeps moving at the same speed in a straight line, unless an unbalanced force acts on it.
It is also called the law of inertia, because objects resist changes to their motion.
So remember, motion only changes when an unbalanced force acts.
Curriculum
Where this fits
- British Columbia, Grade 6
Science, Physics: Newton's three laws of motionBC6-SC-10
Next: Newton's Second Law: Unbalanced Forces Cause Acceleration
The outcomes and strands follow the British Columbia curriculum.
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