Hi boys and girls, Miss Jess here, and today we're going to talk about: SHADOWS.
First of all, what is a shadow?
A shadow is the dark shape made when something blocks light from a light source like the sun, a flashlight, or a campfire. The earth's shadow is called an umbra, and it causes lunar eclipses when the conditions are right and the moon moves through it.
Sometimes objects can block light which means that no light is able to pass through that object. An object from which no light can pass through is called an opaque object. The easiest example is our body.
Stand in the way of a beam of light. Ask someone to stand behind you and spot the beam of light. The person behind you will see no light since your body did not allow it to pass. Whenever light is not able to go through an object, it creates a dark area around the object. This patch where the light can not reach is called a shadow. Opaque objects create clear dark shadows.
In this video, I show you what makes a shadow, a shadow and the difference between clear and opaque objects on the wall.
Why do shadows keep changing sizes?
The size of the shadow depends on the angle at which the light is falling on the object. Your shadow keeps changing throughout the day. It is longest in the early morning and the late afternoon? At noon, when the sun is overhead there is little or no shadow at all. Why? The position of the sun changes throughout the day, thus changing the angle at which the rays fall on the ground.
A long time ago people tracked the length of shadows throughout the day to keep track of time. The world’s earliest clock was a sun clock.
This video explains more about shadows:
Book: The Day I Met my Shadow
Shadow activities at home!
Make shadow art: If it's a sunny day, you can have a parent or brother/sister trace your shadow with chalk, or you can trace their shadow. You can also trace different objects like a leaf shadow!
2. Shadow puppets on the wall: For hundreds of years, people would practice story-telling often using shadows. You can use your hands in different ways or a few objects to make a puppet show or story for your family on the wall!
3. Dance with your shadow: Turn on some good music and dance outside with your shadow! You can also play shadow tag with family members to try to "catch" your shadow. It's great exercise and lots of fun!
4. Take shadow pictures: With the help of your parents, you can take cool shadow pictures! Get creative! If you do take some pictures, please share with us.
5. Human Sundial: To see how the sun moves throughout the day, you can do a science experiment with your shadow. What you'll need is chalk and a big enough area to do a few tracings. You'll mark a spot where you will stand on throughout the day, and someone will trace your shadow. As the day goes on, you'll go back to the spot and trace again. A few different times could be: 8:30 am, 10:30 am, 12:30 am, 2:30 pm, and 4:30 pm. You will see how the shadow will move!
We hope you had fun learning about shadows today boys and girls! Goodbye!
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