In your previous work on shadows you have found out that when light from a luminous source falls on an object, like a vase, that object blocks some of the light rays which then bounce off it. This means that they don't reach the area behind the object and that causes an area of darkness to form which we call a shadow.
In this worksheet we'll consider how the shadow formed is affected by where the object is in relation to the light.
Here's a picture of Fido and his shadow on the ground.
In what ways do you think his shadow would be different if Fido was stood on his garden wall looking at his shadow further away below him on the path?
Tick all the answers you think are right.
Shadows move their position as the direction of the light changes.
Here's a picture of a plastic duck being lit up by a torch:
Look at the three possible shadows compared to where the torch is.
Which one do you think is correct?
Imagine that the duck in question 2 was lit not by a torch but by two different things: the Sun and the Moon.
Do you think that the shadow would get sharper or dimmer compared to that made with a torch?
Match the result to the light source.
As you know the Sun moves across the sky during the day. As it does so the shape of the shadows it makes changes.
Here are five pictures of a house, its shadow changing with the position of the Sun in the sky:
Match the picture to the time of day you think it represents according to where the Sun is and the shape of its shadow. By the way, you're looking south!
Which of the following do you think will make the most distinct and clearest shadows?
Tick all the ones you think will.
Here's a picture of a torch being shone at a vase:
A shadow falls on the screen behind.
Here is a list of possible ways in which the shadow could be made to be BIGGER - tick all the ones you think are correct.
Mrs. Bates was investigating how the size of shadows changes with her science class. They were using a teddy bear and a torch:
Mrs. Bates asked her students to move the teddy bear towards the screen, measuring the distance to the screen and the size of the shadow as they did so.
Here are their results:
|Distance to screen/cm||50||40||30||20||10||0|
|Size of shadow/cm||55||48||41||34||27||20|
Looking at the results by how much does the image size change each time the students move the teddy bear 10cm closer to the screen?
Mrs. Bates helped her class to produce a line graph of their results:
She then asked her students to write down what they thought the graph showed them. Here is what three of them wrote.
Tyler: "as we moved the teddy bear towards the screen it got bigger."
James: "as the teddy bear moved further from the light the image got smaller."
Jessica: "the shadow was smaller when the teddy bear was closer to the screen."
Who do you agree with most?
Here is their graph again:
Looking at the graph what do you conclude about how the size of the shadow changes as the teddy bear is moved towards the screen?