Describing Motion Around Us: common misconceptions

If your child says… “If something moves, it moves relative to everything.”

Ask together

Does the coin change its place on the tray?

What’s true

The same object can move relative to one reference and remain still relative to another.

If your child says… “Displacement counts every part of my route.”

Ask together

Does the Start-to-Finish arrow include the extra distance travelled to Turn?

What’s true

Only start and finish determine displacement, whose size cannot exceed the distance travelled.

If your child says… “Returning makes my average speed zero.”

Ask together

Did the walk cover any distance before returning to the start?

What’s true

Returning cancels displacement, but the distance travelled remains positive.

If your child says… “Negative acceleration always means slowing down.”

Ask together

Does changing from 2 m/s to 6 m/s make the cyclist slower?

What’s true

Speed increases when velocity and acceleration point the same way, even when both are negative.

If your child says… “A flat line means steady movement.”

Ask together

During the flat section, does the position change as time passes?

What’s true

A horizontal position-time line records an unchanged position as time passes.

If your child says… “The area gives acceleration.”

Ask together

What unit comes from multiplying m/s by seconds?

What’s true

Areas above the time axis add displacement, while areas below subtract from it.

If your child says… “These equations work even when acceleration keeps changing.”

Ask together

If acceleration changes during these 3 s, which single value could these equations use?

What’s true

These equations apply to straight-line motion only when acceleration stays constant throughout the interval.

If your child says… “Steady speed means there is no acceleration.”

Ask together

Does your fingertip keep moving in the same direction as it traces the rim?

What’s true

Changing direction changes velocity even when speed stays the same.