Energy is the ability to work, it is an instigator and cause of everything that surrounds us. We use energy to power motors and devices. It lights up our cities. We use it to warm our homes up and cool them down, to cook and boil water. Sun energy provides us with light during the day, it enables plants to grow. Herbivores obtain energy while feeding on the plants and carnivores when eating their prey. All we do is connected with energy.
A very important aspect of energy is that it can’t appear or disappear, but it can only be transformed from one form into another. This is the Law of energy conservation, which has been formulated in the 12th century.
PIECE OF BREAD WITH BUTTER CONTAINS 315 KJ ENERGY, WHICH IS SUITABLE FOR:
WHY IS IT IMPORTANT?
The modern lifestyle requires a rise in energy needs in order to be able to keep up with the ever growing life standards. Seeing how we need energy for everything we do and those resources are limited, we need to use what we have rationally. This particularly means swapping fossil fuels with renewable energy sources. Using energy wisely is a responsibility of each and everyone of us to ensure that enough energy will be left for future generations. People will always need energy to live and this is why we need to think about the needs of future generations when using it.
Energy is measured in many ways and many units. Basic unit of measure is joule (J), named after an English physicist James Prescott Joule (1818.-1889.). He has found that heat is one form of energy.Energy can be placed in other units such as calories or kilowatt-hours. Ratio between different energy units is constant: one cal is 4.18 J, 1 KWH is 3.6 million J.