How Shadows Form
Recognise that shadows are formed when light from a source is blocked by an opaque object, and find patterns in how shadow size changes
What a learner can do afterwards
- Explain that a shadow forms because an opaque object blocks light from reaching a surface
- Describe the pattern: shadow gets larger when object moves closer to the light source
- Predict the shape and relative size of a shadow given the position of light and object
The lesson
Light travels in straight lines until something stops it. When an opaque object sits in the path of light, it blocks that light, so no light lands on the surface behind it. That dark, blocked patch is a shadow.
Mia shines a torch straight at a toy dinosaur standing in front of a wall. The dinosaur is opaque, so it stops the light from getting through. A dark dinosaur-shaped patch appears on the wall behind it. That patch is the dinosaur's shadow.
Shadows do not stay the same size. Move the toy closer to the torch, and its shadow grows bigger on the wall. Move the toy away from the torch, closer to the wall, and its shadow shrinks back down.
To guess how big a shadow will be, check how close the object is to the light. Near the light means a bigger shadow. Near the wall means a smaller shadow.
An opaque object blocks light and makes a shadow, and moving it closer to the light makes that shadow bigger.
Watch it
Where it sits
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.