Q1.
We see vehicles move on our busy roads. What do cars and scooters need to keep running?
Answer
They need fuel — petrol or diesel. Fuel is to a vehicle what food is to us.
Food is the source of energy for us.
Petrol and diesel are the source of energy for vehicles.
Petrol and diesel are the source of energy for vehicles.
| Vehicle | What it usually runs on |
|---|---|
| Scooter, motorcycle, car | Petrol |
| Bus, truck, tractor | Diesel |
| Auto-rickshaw | CNG or petrol |
| Electric car, e-rickshaw, electric bus | Electricity, stored in a battery |
| Bicycle | The rider's own energy — that is, food |
Why fuel is needed: A vehicle is a machine, and a machine cannot move by itself. Burning a little petrol or diesel inside the engine releases energy, and the engine turns that energy into the turning of the wheels. When the tank is empty there is no energy left, and the vehicle stops.
Notice the bicycle: it is the only one in the list with no tank. The energy comes from the rider's legs, and the rider's legs got it from food. That is why a bicycle makes no smoke at all.