Light: Mirrors and Lenses: common misconceptions

If your child says… “The rim tells me the mirror type.”

Ask together

Did the rim change when you turned the ladle?

What’s true

The reflecting surface’s curve decides the type.

If your child says… “An upright image means a flat mirror.”

Ask together

Does the spoon’s outward side give an upright image?

What’s true

Curved mirrors can also give upright images.

If your child says… “We measure both angles from the mirror.”

Ask together

Would straight-on light make a zero angle with the surface or the normal?

What’s true

Both angles are measured from the normal.

If your child says… “Equal angles tell us everything about reflection.”

Ask together

Which rule keeps the outgoing ray inside the shaded plane?

What’s true

The shared-plane rule also fixes which way the reflected ray travels.

If your child says… “The hollow side always spreads light apart.”

Ask together

Do the reflected arrows from the concave mirror approach each other or separate?

What’s true

A concave mirror brings parallel light near its central line together.

If your child says… “Convex lenses spread parallel light apart.”

Ask together

Do the outgoing arrows behind the thick-centred lens approach each other?

What’s true

Ordinary convex lenses in air bring parallel rays near their central line together.

If your child says… “Convex lenses always enlarge.”

Ask together

What changes between the nearby and distant objects’ image boxes?

What’s true

A convex lens’s image depends on object distance.

If your child says… “My eye’s lens stays the same shape.”

Ask together

Which lens is rounder when light reaches the same back surface?

What’s true

Muscles change the lens’s shape as focusing distance changes.