Environment & Human Behaviour

We all use energy all the time. We use energy to drive a car, cook a meal or even to eat that meal. But the energy we use does not really go away after we use it. The law of conservation of energy states that energy is always conserved. Energy only changes its form when we use energy. In more practical terms, energy changes from a more useful form to a less useful form when we use energy.

When we drive a car, the useful fuel in the car’s tank burns to provide kinetic energy for moving the car. Our action of driving also creates a waste or loss of energy, largely heat energy. But the total energy does not change in this process.

Now, a question: how much of fuel’s energy gets used as useful kinetic energy when we drive a typical car?

A. 25%

B. 50%

C. 75%

D. 90%

Without googling, what do you think is the correct answer?

After all, cars have been mass-produced for more than a century and invented much earlier. By now, perhaps engine technology has improved so much that most of the chemical energy is converted into useful energy? Maybe 75% for most cars and 90% for the latest gasoline cars?

Are you surprised that the correct answer is A? Yes, most of the energy embedded in fuel’s chemicals is lost to the environment as heat. It’s like we are pumping heat energy into the atmosphere whenever we drive a car or any vehicle for that matter.

And before you go, where do you think that the useful kinetic energy ends-up?

Sources:

Energy losses from Energy Education and European Environment Agency

A history of the evolution of cars