The Flow of Energy – The Story of Photosynthesis

The Flow of Energy - The Story of Photosynthesis

The flow of energy

We take for granted the ease with which we can put on a light at home. Our refrigerators continuously run, and if we want hot water, we flick a switch, and the water heater does the work. Power plants that generate electricity may be hundreds of kilometers away, and yet through a chain of substations and distribution lines, energy from the power station comes right into our homes. 

When you put on an electric switch, there is a common misconception that somehow electrons flow from the power station into your device. We use what is called Alternating Currents. Imagine a long line of people standing very close to each other. If one person starts pushing people to the left and the right, all the people get affected, and everyone in the line begins shaking, left and right. Similarly, electrons all along the electric lines jiggle back and forth and what is transmitted to us is this back-and-forth energy.  

More than electricity, the incredible flow of energy and the source of all of our lives is called photosynthesis. We happily eat our food, vegetarian or non-vegetarian, without the slightest thought as to the fundamental process that gives us this gift. Photosynthesis (the ‘putting together with light’) is the flow of energy from the Sun into plants and then eventually into us. Ultimately, we are eating and being sustained by the energy of the Sun.

Trees are made out of the air

The author Marcus Chown writes that photosynthesis is “mind-bogglingly clever.” The great physicist Richard Feynman said, “People look at a tree and think it comes out of the ground, that plants [get their matter] out of the ground.” “But” he explained that the substance and matter trees “come out of the air!”

Trees are solid and heavy. How could they ever be made out of air? This is where photosynthesis comes into the picture. Plants get energy from sunlight. This energy is used by a protein in plants called chlorophyll (green in colour) that combines hydrogen from the water vapour in the air and carbon from the carbon dioxide in the air to build carbohydrates (the substance of the tree). This almost miraculous process results in almost 95 percent of a tree being made out of the air’s hydrogen and carbon atoms.

Its not only food – its oxygen

Whether we are vegetarian or non-vegetarian, the basic food source for life on earth is due to photosynthesis. However, we benefit from more than just food which we can eat. In the process of making carbohydrates, leaves give off oxygen as a by-product of photosynthesis. Oxygen allows us to breathe, and this is the second gift to us from a most incredible natural process.

So many interconnections

The story continues. In fact, the fuel we use in our coal-fired power plants and in the petrol for our cars comes from trees and other life that has died and composted over millions of years. Richard Feynman called this the “stored energy of the Sun.” We release this stored energy when we burn this fuel by flicking a switch and putting a light on in our homes. 

So, next time you sit down to eat your meal or, every time you take a breath or use electricity or travel in your car, remember and perhaps meditate on the story of photosynthesis. This shows how many are the beautiful interconnections of life.

© Kaikhushru Taraporevala

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