"The law of conservation of energy states that energy cannot be created or destroyed, but it can be transformed"
The law of conservation of energy is one of the fundamental laws of physics, and it states that energy cannot be created or destroyed, however it can be transformed.
We have many examples in daily life that shows the application of this law. An example is when an object falls to the ground: initially, the object has gravitational potential energy, and when it falls down, this potential energy is converted into kinetic energy (because the object gains speed).
There are some situations, however, where energy seems to be created or destroyed: for example, during a car accident, it seems that the whole initial kinetic energy of the car has been destroyed when the car stops after the crash. This is not true: in fact, the kinetic energy of the car has just transformed into thermal energy and sound energy during the crash.