Skip to main content

Why Do Shadows Happen?

Discover why light is essential for seeing and how our eyes transform light into vision. Perfect for young scientists eager to understand the world through fun, engaging content.

Listen to this Episode

Loading player...

February 25, 2025
3:54 listen
Fizz, Pop, Wow!

Shadows appear whenever something blocks light's straight-line path! These dark silhouettes form behind objects because light can't bend around them. The size and shape of shadows change throughout the day as the sun's position shifts, creating longer shadows in morning and evening and shorter ones at noon.

What Is a Shadow?

Have you seen your shadow following you around on a sunny day? Or made shadow puppets at night? Shadows aren’t invisible things—they happen because something blocks light. Light travels in straight lines, and when an object gets in the way, it stops the light, creating a dark spot behind it—a shadow!

How Do Shadows Form?

If you stand in the sun, your body blocks the light, and a shadow appears. If you put your hand in front of a flashlight, it blocks the beam and casts a shadow on the wall. No light = no shadow. Simple science!

Why Do Shadows Change Size?

Shadows grow and shrink based on the angle of the light. In the morning and evening, the sun is low, making long shadows. At noon, the sun is high, making short shadows. You can test this with a flashlight too—closer = bigger shadow, farther = smaller shadow.

Try It: Sun Shadow Tracker

See how your shadow changes during the day.

Try It: Sun Shadow Tracker

Materials Needed:

  • Chalk or rocks
  • Sunny outdoor spot

Steps to Follow:

  1. Stand in the sun in the morning and mark your shadow with chalk or a rock.
  2. Come back at noon and check again—your shadow should be shorter!
  3. Check once more in the evening—is it long again?
  4. This shows how the sun’s angle changes your shadow.

Try It: Hand Shadow Fun

Create cool shapes and explore how shadow size changes.

Try It: Hand Shadow Fun

Materials Needed:

  • Lamp or flashlight
  • Dark room

Steps to Follow:

  1. Turn on your flashlight or lamp in a dark room.
  2. Hold your hand up to make different shadow shapes—like a bunny or bird!
  3. Move your hand closer to the light. What happens to the shadow?
  4. Move it farther away. What changes?

Your Challenge

Try the Sun Shadow Tracker and see how much your shadow changes during the day. Or create a shadow puppet show with a flashlight—how many animals can you make?

Your Challenge

Try the Sun Shadow Tracker and see how much your shadow changes during the day. Or create a shadow puppet show with a flashlight—how many animals can you make?

Key Takeaways

  • Shadows form when something blocks light, which travels in straight lines.
  • The size of a shadow depends on the angle and distance of the light source.
  • Morning and evening sun makes long shadows; midday sun makes short ones.
  • You can experiment with light and shadows using flashlights and your hands!