Teacher professional development and classroom resources across the curriculum
Teacher professional development and classroom resources across the curriculum
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So think about why the shadows are there. A shadow is not a
thing in itself, but rather the absence of light. In this activity,
the "bright grass" is illuminated by four lights. In a shadow, it is
illuminated by only three; one is blocked by the player. You can see multiple shadows whenever you have multiple light
sources. If you have more than one light in a room, your hand will
cast more than one shadow. If you have a chandelier with only a few
bulbs, each bulb will cast a separate shadow, giving you a bouquet
of shadows in the same shape as the chandelier. (If there are lots of
bulbs, or large light sources such as fluorescent bars, the shadows
get washed out.) But why are short shadows darker? On the sports field here, if the
light is nearby, the angle will be higher and the shadow will be
shorter. Now here's the tricky part: the nearby light, being closer,
provides more of the illumination. The other three lights are weaker,
being farther away, so the field in shadow is darker than if the
player were in the middle of the field. You can see this effect in everyday (or every-night) life if you
live where there are streetlights. Go for a walk down the street at
night. As you proceed from light to light, you will see two shadows:
one from the light behind you and one from the light before you. As you
approach a light, the shadow behind you will darken and shorten,
while the one in front of you gets more and more faint. There are two phenomena here: the fact of multiple shadows and the
effect of distance on their darkness. The first is easy for young
children to understand; as they get older, they can come to
understand the second. Back to Where Is the Player? |
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