What is Earth's main source of daytime light?

How are stars grouped as light sources?

What must an object do to be a light source?

How is a burning candle classified as a light source?

How are Christmas lights and stars classified as light sources?

Why does the Moon look bright?

Which pair contains both a natural light source and an artificial light source?

Mika looks through a hole into a completely dark box containing clay. What can she see inside?

What should Mika do to see the clay without removing it from the dark box?

What path lets Bea see a soccer ball under a lamp?

What shape is the path of light through air?

In what directions does a glowing bulb without a shade send light?

How must the holes in the cards be arranged for a flashlight beam to reach the wall?

In the hole experiment, Rico shifts one card. Why does the wall's bright spot disappear?

What happens when a flashlight beam meets an opaque object?

Why can you see a classmate's face through clear plastic but not through a thick folder?

The picture shows a lamp, card, and screen. What is the dark patch on the screen called?

A lamp is left of a card. Where should a screen go to show its shadow?

A tennis ball sits between a flashlight and a wall. What shape will its dark patch have?

Can a tree make a shadow on a bright day?