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The Albedo Effect. Lab Data Table. Lab Question. The color of paper with the highest MAX temp. is said to have a lower ALBEDO - it can absorb more heat so therefore it reflects less. Which color had the lower albedo? ANSWER: Black. The Albedo Effect - Notes.
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Lab Question • The color of paper with the highest MAX temp. is said to have a lower ALBEDO - it can absorb more heat so therefore it reflects less. Which color had the lower albedo? • ANSWER: • Black
The Albedo Effect - Notes • Albedo is a Latin word which means whiteness. • We use it to describe how bright something is. • We need to understand albedo in order to understand the climate of the Earth.
When light hits an object, three things can happen to it: • Reflected (bounce off) • Transmitted (go through) • Absorbed (stay in)
Scientific Definition • Albedo is the ratio of the light reflected by an object compared to the total amount of light it receives. • The albedo of an object ranges from zero (no light reflected) to one (all light reflected). (0-1) • Albedo can also be expressed as a percentage %.
A white object reflects light more/absorbs less • A black object reflects less light/absorbs more
The albedo of the Earth • The average albedo of our planet is around 0.3 • This means that 30% of the sunlight that strikes the Earth is re-emitted (reflected) back into space.
Percentage albedo for different types of surfaces SURFACE TYPE % Albedo • Fresh snow 80-85 % • Dirty snow 50-60 % • Grass 20-25 % • Forest 5-10 % • White paint 80 % • Black paint 5 %
The average temperature of the Earth's surface is ~ 15 0C at present • What the temperature would the Earth be if it were…. Forest only Desert only Ice only Ocean only
The albedo of clouds • Clouds affect the albedo of the Earth • Clouds reflect more sunlight back to space than blue sky • The albedo of a cloud depends on many factors including: • height of the cloud • overall size of the cloud • number of water droplets inside the cloud • The color of a cloud, from bright white to dark grey, depends on the number, size and color of water droplets in the cloud.
Albedo of Clouds Cont’d • Big droplets have a large surface area and reflect more light than small droplets. • Large numbers of water droplets leads to bright white clouds. • If you are under a big cumulonimbus cloud, it's dark out because the sunlight can't pass easily through the clouds. • From space, however, the same cloud would look bright white because it actually has a high albedo. • In contrast, a cirrus cloud is nearly transparent to sunlight but looks grey from space because it has a low albedo.
Answer • Because asphalt is darker, it has a lower albedo and therefore absorbs more heat.