What are fossil fuels?

The Latin word fossils means 'unearthed' or 'excavated' because we need to excavate these fuels. In other words, they are buried deep inside the Earth and we need to dig them out. Fossil fuels are made of plants and animals that died millions of years ago and were converted - by the processes inside the Earth - into coal, crude oil, or natural gas. The energy stored in these fossils can be released and used by burning them.
Searching for coal or crude oil, pumping out these fuels from the depths, and transporting them require a lot of effort and time. The crude oil must then be converted into petrol for cars.

How is coal formed?

Coal is essentially made from dead plant material. Around 300 million years ago, in the Carboniferous period, huge ferns grew in the tropical climate and dead plants sank in the swamp. The dead plant layers forced oxygen out and left rich carbon deposits.
The pressure of this layer pressed the water out of the remains of the plants slowly. This first gave rise to brown coal. Hard coal was formed when the pressure increased further. It is found in deeper layers and is a high-quality fuel. It is dug out in mines. Brown coal, on the other hand, is mined by using excavators.

(all the image taken from google image for educational purpose so credit goes to google image )