How light can trick us

 Apparent depth  Flattened sun and sunsets  Mirages  Shimmering  Rainbows

 The depth that an object appears to be due to the refraction of light in a transparent medium  Eg. Looking into water from above  Light will refract away from the normal travelling from water into air because air is faster  Our brains don’t acknowledge that the light is refracted, so we extend the refracted ray straight back, creating a virtual source of the light rays

OBJECTS IN WATER APPEAR CLOSER TO THE SURFACE PENCIL IN WATER APPEARS BENT

 When the sun nears the horizon, it appears to be flattened during a sunset  Light from the bottom of the sun is refracted more than light from the top  This is because the air lower in the atmosphere is more dense, slowing the light more  Rays from the bottom of the Sun have a greater angle of incidence

 A virtual image that forms as a result of refraction and total internal reflection in Earth’s atmosphere  This is the result of light travelling through different air temperatures  The index of refraction decreases as air gets warmer, causing the light to bend farther away from the normal  Total internal reflection occurs in the hottest layer, usually on the Earth’s surface  The ray travels back through to the cooler air and bends back toward the normal

 When the light reaches our eyes, we think it travelled in a straight line  This results in an image of the sky appearing to be on the pavement or sand

 Also caused by light refracting through different air temperatures  Air closer to the lake is warmer, so the light refracts in the same pattern as it does near hot pavement  Total internal refraction occurs in the lowest, warmest layer causing multiple virtual images on the water’s surface

 Rainbows are a result of the dispersion of white light into its 7 colour components  Remember: red light is refracted less than violet due to its speedROYGBIV  Rainbows are produced by water droplets 3 steps: Dispersion of white light by the rain drop Partial internal reflection at the back of the rain drop Refraction of the light exiting the rain drop

 Our eyes see the final refraction, and projects these rays backwards to form a virtual image of a rainbow  You can only see a rainbow when the sun is behind you

Apparent Depth Pencil_in_a_bowl_of_water.png Water Mirages Mirage.jpg simpson.jpg Mirage Diagram refraction/mirage.jpeg

Moon shimmering /Moon dcr.jpg ska_074.JPG Rainbow pictures.com/data/media/13/rainbow-over-the- muldrow-glacier_1127.jpg