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Images of Immersed Objects
Name: Ja
Status: student
Grade: 6-8
Location: OH
Country: USA
Date: 4/1/2005
Question:
Why does objects in water sometimes look smaller and then
sometimes look bigger? I know it is due to the water refracting light, but
sometimes, if there is a golf ball in the middle of the globe, and then
there is a empty space of air, then there is a layer of glass with water
and finally, there is the last layer of glass, the golf ball inside
appears to be smaller than real life than normal, or even bigger. Why is
that?
Replies:
I assume in this case you are talking about looking through the bowl at the
golf ball. In this case, the entire bowl of water is acting like a
magnifying glass. The increased density (and the associated difference in
actual speed of light) causes light to diffract (bend) creating this
illusion.
Ryan Belscamper
Ja,
When light passes through materials with curved shapes, the light can change
direction. Your eyes tell how tall something is by light from the top and
light from the bottom of the object. If light from the top and the bottom
are both coming from almost the same directions, the object looks small. If
they come from very far apart directions, the object looks large. When the
light changes directions, light from the top and light from the bottom can
appear to come from very far apart directions, or very close together
directions, when really they do not. This makes the size look different
than what it really is.
Dr. Ken Mellendorf
Physics Instructor
Illinois Central College
This is a questions from:
Paul Hewitt "Conceptual Physics" Addison-Wesley
The helicopter leaves the ground with the ground's eastward velocity. It
maintains that velocity unless acted upon by an external force. So the
point of departure and the helicopter are both moving eastward at the same
rate. The aircraft appears to hover.
---Nathan A. Unterman
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Update: June 2012
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