Kia Ora,
This week in R10 we have been learning about light and shadows. We had to write an explanation of light and shadows. We had to read about some light and shadows.
Shadows
Have you ever noticed a dark image next to you, following you wherever you go and sometimes it disappears? This is called a shadow that happens when light travels and can not pass through objects. This writing will be explaining about different types of shadows forming, parts of shadows, and why shadows change.Â
How Are Shadows Formed?
For a shadow to form, three things are needed: a light source like the sun or a lamp, an opaque object that blocks the light like your body, and a surface for the shadow to appear on like the ground. Light travels from its source in straight lines called rays. When an object gets in the way of these rays, it stops them from reaching the surface behind it. The dark area where the light cannot reach is what we see as a shadow.
The Parts of a Shadow
Shadows are not always uniformly dark. They often have two distinct parts: the umbra and the penumbra. The umbra is the darkest, central part of the shadow, where the light source is completely blocked by the object. If you are standing in the umbra of a solar eclipse, for example, the sun is totally hidden. The penumbra is the lighter, outer part of the shadow, where the light source is only partially blocked. This is why the edges of a shadow often look fuzzy or blurry.
Why Do Shadows Change?
Shadows don’t stay the same. You can see this by observing your own shadow throughout the day. Its size and shape change depending on the position of the light source. When the sun is low in the sky, during the early morning or late afternoon, it hits objects at a low angle, creating long shadows. However, when the sun is directly overhead around noon, the light hits objects from above, making shadows very short. The science behind this is that light always travels in a straight line, and the shadow is a projection of the object blocking that light. As the angle of the light changes, so does the shape and length of that projection.
In summaryÂ
So, as we’ve discovered, the way shadows appear and change isn’t a mystery, but simple science at work. We’ve learned that a shadow is created when an object gets in the way of a light source, that it has a dark middle and lighter edges, and that its size and shape depend entirely on the angle of the light. The next time you’re outside, have a look at your own shadow and see if you can spot the fuzzy penumbra around the edges. Â