Remember, as a member of the Science Bus Club you can ‘Ask Albert’ a question about any of the topics. So if you’re not already a member join today!!
Shadows
Shadows come about when light travelling from a light source is blocked.
Have you ever read the book Peter Pan? He thought he could catch his own shadow but that we know is impossible!!
Have you ever seen your shadow on a sunny day? The light from the sun is blocked and the area you are blocking appears as a shadow on the ground. The sun is the source of light and you are the object blocking it.
Can you think of any other sources of light? How about a torch? That’s a source of light and will still cast a shadow.
Have you ever heard of a lunar eclipse? That is when the earth blocks the light from the sun and casts a shadow that stretches all the way to the moon.
When your shadow is caused by the sun, it will change during the course of the day. This is because the earth rotates and varies the angle the light hits you. As the angle becomes more obtuse (wide) the longer your shadow will become.
Try this experiment:
On a sunny day go out into your school playground or garden and stand so that your shadow appears on the ground. Now mark out either with chalk or with sticks, (a) exactly where you are standing & (b) mark out your shadow. Continue doing this every hour remembering to stand exactly in the same place, repeatedly marking your shadow each time. At the end of the day, you will see how your shadow moved across the ground. As the earth moved so did your shadow, this is because as each hour went by the source of light was arriving and hitting you at a different angle.
To complete this experiment use a chart to plot the time of day and the length of your shadow.
Where Does The Sun Shine
The sun shines and gives off its energy all the time. When it gets dark on earth, you are facing away from the sun. However, the sun is still shining!! The other side of the earth is still in light.
Did you know that when it is 6pm here in the UK it is only 1pm in the afternoon in New York (in other words they are five hours behind us)!!
Try this:
Get an orange and put a dot on it, anywhere on the orange … that’s you!! Now shine a torch on one side representing the Sun. Do this experiment in a dark room. As you can see, some of the earth is in light and some is in dark. Cool!!
Sundials
Before clocks were invented, people used an ingenious method to tell the time. They used the sun and the shadows it created, this was a sundial. As the earth spun throughout the day, the shadow always pointed at a different spot on the dial.
It was an ingenious way to tell the time.
Remember, as a member of the Science Bus Club you can ‘Ask Albert’ a question about any of the topics. So if you’re not already a member join today!!
