Science 5: One More Look at the Fossil Fuel Cycle

But do we know the process it took to get from the original forms of life to fossil fuels? [Boy in a lab using a microscope]

It's a pretty complicated, delicate recipe.

Seriously, it's way more difficult than the recipe for even the fanciest of cakes.

Plus, it takes a few billion years, which is a lot longer than most kitchen timers can measure.

It all started billions of years ago, when the only living things on Earth were tiny

little bacteria that lived in the ocean. [Bacteria floating round in the ocean]

In time, those bacteria made their way to the surface of the ocean…

…and with the help of energy from the sun, they eventually evolved into green plants.

These plants made some big changes.

Unlike humans and other animals, who inhale oxygen and exhale carbon dioxide, plants do [Bear breathing in oxygen]

the opposite.

They take in carbon dioxide, and release oxygen.

So over millions of years, all of these green plants gradually released more and more oxygen…

…until there was enough oxygen for animals like us to survive. [Tree giving off oxygen with birds flying above]

You might not like Brussels sprouts, but you owe their ancestors your life.

Maybe send them a Hallmark card, or something.

These plants did more than just create oxygen, though.

They also made carbon chains, which animals would then eat.

So after a while, there were a whole bunch of carbon chains all over the place.

When these plants and animals died, some of them, and their carbon chains, would get buried [Dinosaur collapses onto the floor]

under stuff like rocks, dirt, or silt.

And over millions of years, a mix of pressure from above…

…and heat from below turned these carbon chains into fossil fuels.

And sure, a puddle of oil is nowhere near as appetizing as a birthday cake, but that's [Cake tray is removed from an oven]

why it's always important to check your recipe before you start baking.