SHADOWS AND ECLIPSES HOW ARE SHADOWS FORMED Shadows

SHADOWS AND ECLIPSES

HOW ARE SHADOWS FORMED Shadows are formed when an opaque object is placed in the path of light Shadows are formed because light travels in a straight line and cannot bend around the opaque object thus a region of darkness where the light cannot reach is formed. The size of the shadow depends on how much light is being blocked by the opaque object.

POINT AND EXTENDED SOURCES OF LIGHT Point source - small source of light Extended source – large source of light

UMBRA AND PENUMBRA The region of total darkness in a shadow is known as the umbra The region of partial darkness is known as the penumbra A point source of light forms an umbra An extended source of light forms both the umbra and the penumbra.

SHADOW FORMATION WITH DIFFERENT SOURCES OF LIGHT Extended source Point source

SOLAR AND LUNAR ECLIPSE Solar and lunar eclipse are the result of shadow formation. A solar eclipse occurs when the moon’s shadow forms on the earth. A lunar eclipse occurs when the earth’s shadow forms on the moon. Remember the moon orbits the Earth and the Earth orbits the Sun.

SOLAR ECLIPSE Occurs when the moon is between the Earth and the sun. People located in the umbra will experience a total solar eclipse whereas people located in the penumbra will experience a partial eclipse

TOTAL SOLAR ECLIPE

PARTIAL SOLAR ECLIPSE

LUNAR ECLIPSE Occurs when the Earth is between the sun and the moon Occurs during a full moon A total lunar eclipse can be seen when the moon is directly behind the Earth A partial lunar eclipse occurs when only a part of the Earth’s shadow falls on the moon

TOTAL LUNAR ECLIPSE

PARTIAL LUNAR ECLIPSE

BLOOD MOON (TOTAL LUNAR ECLIPSE) Earth’s atmosphere extends about 50 miles (80 kilometers) above Earth’s surface through which the sun’s rays pass. This light causes the moon to appear red Next total lunar eclipse will occur on the 8 th October, 2014.

SUMMARY Shadows are formed when an opaque object blocks the path of light A point source of light forms an umbra An extended source of light forms both the umbra and the penumbra. A solar eclipse occurs when the moon’s shadow forms on the earth A lunar eclipse occurs when the earth’s shadow forms on the moon. Both solar and lunar eclipses can be total or partial

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