The trees around me burst into colorful flames of yellow, red, purple, orange, brown, pink, etc. This is my first autumn and I love it. This pageantry of colors is such a pleasant scene to behold.
But why do the leaves change color in this part of the world? So i reviewed my science books and searched the internet and found amazing facts about trees and what makes autumn so beautiful.
COLORS OF LEAVES
Leaves are green because of the presence of CHLOROPHYLL. Chlorophyll is the molecule that absorbs sunlight and uses its energy to synthesize carbohydrates from carbon dioxide and water.
Some leaves also has CAROTENOIDS and ANTHOCYANINS but they are masked with the green coloration of the chloropyll.
CAROTENOIDS - produces yellow, orange and brown colors to leaves and fruits
ANTHOCYANINS - gives red color to leaves
WHY THEY CHANGE COLORS
Sunlight regulates the production of chlorophyll.
As the Earth rotates on it's tilted axis around the sun, different parts of the Earth receive higher and lower levels of radiant energy. This creates the seasons. In the tropics the sun doesn't shift up and down in the sky as much. This means that the length of day temperature doesn't vary as much. So countries near the equator only have two seasons - rainy and dry. That explains why trees there bear green leaves all year long - well, except when the leaves die they turn brown.
During autumn, the north pole moves away from the Sun. The Sun rises lower in the sky so the days continue getting shorter and temperature drops. (This happens in temperate regions like North America). The lower temperature and fewer hours of sunlight signal the tree to go into storage mode for the winter. The chlorophyll now starts to break down, causing the green in the leaves to disappear - allowing the carotenoids which was hidden due to the presence of chlorophyll to show through.
The range and intensity of autumn colors is greatly influenced by the weather. Low temperatures destroy chlorophyll, and if they stay above freezing, promote the formation of anthocyanins. Bright sunshine also destroys chlorophyll and enhances anthocyanin production. Dry weather, by increasing sugar concentration in sap, also increases the amount of anthocyanin - thus the red color of leaves we see.
References:
http://scifun.chem.wisc.edu/CHEMWEEK/fallcolr/fallcolr.html
http://chemistry.about.com/od/howthingsworkfaqs/f/fallleafcolor.htm
http://www.sciencemadesimple.com/leaves.html
But why do the leaves change color in this part of the world? So i reviewed my science books and searched the internet and found amazing facts about trees and what makes autumn so beautiful.COLORS OF LEAVES
Leaves are green because of the presence of CHLOROPHYLL. Chlorophyll is the molecule that absorbs sunlight and uses its energy to synthesize carbohydrates from carbon dioxide and water.
Some leaves also has CAROTENOIDS and ANTHOCYANINS but they are masked with the green coloration of the chloropyll.
CAROTENOIDS - produces yellow, orange and brown colors to leaves and fruits
ANTHOCYANINS - gives red color to leaves
WHY THEY CHANGE COLORS
Sunlight regulates the production of chlorophyll.
As the Earth rotates on it's tilted axis around the sun, different parts of the Earth receive higher and lower levels of radiant energy. This creates the seasons. In the tropics the sun doesn't shift up and down in the sky as much. This means that the length of day temperature doesn't vary as much. So countries near the equator only have two seasons - rainy and dry. That explains why trees there bear green leaves all year long - well, except when the leaves die they turn brown.
During autumn, the north pole moves away from the Sun. The Sun rises lower in the sky so the days continue getting shorter and temperature drops. (This happens in temperate regions like North America). The lower temperature and fewer hours of sunlight signal the tree to go into storage mode for the winter. The chlorophyll now starts to break down, causing the green in the leaves to disappear - allowing the carotenoids which was hidden due to the presence of chlorophyll to show through.
The range and intensity of autumn colors is greatly influenced by the weather. Low temperatures destroy chlorophyll, and if they stay above freezing, promote the formation of anthocyanins. Bright sunshine also destroys chlorophyll and enhances anthocyanin production. Dry weather, by increasing sugar concentration in sap, also increases the amount of anthocyanin - thus the red color of leaves we see.
References:
http://scifun.chem.wisc.edu/CHEMWEEK/fallcolr/fallcolr.html
http://chemistry.about.com/od/howthingsworkfaqs/f/fallleafcolor.htm
http://www.sciencemadesimple.com/leaves.html
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