Week_6_Online_Lab_Penumbra_Effect_Gizmo.

1. Look at the edges of the shadow. Are they sharp or fuzzy? __They are fuzzy________________________ 2. Move your hand up and down. How does this affect the fuzziness of the shadow? ________ ____The closer it gets the more fuzzy _____________________________________________________________________ 3. Why do you think the shadow has fuzzy edges? ___________________________________ ______The light sources are obstructed and by objects and appear fuzzy ___________________________________________________________________ Gizmo Warm-up The fuzzy edge of a shadow is the penumbra, a region where light is only partially blocked. The Penumbra Effect Gizmo™ demonstrates why penumbras form. To begin, check that the Number of lights is 1. Click the light to turn it on. The gray block casts a shadow. 1. The light is a point source, which means that all of the light rays emanate from a single point. Does the resulting shadow have sharp or fuzzy edges? ______It has a clear defined shadow __________________ 2. Increase the Number of lights to 2. How does this affect the shadow? ________________ ___________________It starts to become fuzzy______________________________________________________ 3. The central, dark part of the shadow is the umbra. Would you be able to see either of the lights if you were standing in the umbra? Explain.