Conservation laws are the fundamental rules of the universe that state certain physical quantities never change over time.

The Law of Conservation of Energy

The Law of Conservation of Energy states that energy cannot be created or destroyed. It can only change from one form to another. For example, when you switch on a light bulb, electrical energy turns into light and heat energy. The total amount of energy remains exactly the same before and after the change. This is why a pendulum eventually stops swinging; its motion energy (kinetic energy) slowly turns into heat due to air friction.

The Law of Conservation of Mass

This law teaches us that matter is neither created nor destroyed in a chemical reaction. If you burn a piece of wood, the wood seems to disappear. However, if you could capture all the smoke, ash, and gases produced, they would weigh exactly the same as the original wood plus the oxygen used to burn it. In nature, particles simply rearrange themselves into new substances.

The Law of Conservation of Linear Momentum

Momentum is a measure of how hard it is to stop a moving object. It is calculated by multiplying mass by velocity. The Law of Conservation of Linear Momentum states that if no outside force acts on a group of objects, their total momentum stays constant. Think of a game of billiards. When the cue ball hits a stationary ball, the cue ball slows down, and the other ball starts moving. The total amount of motion remains shared between the balls, balancing out perfectly.

• Energy: Changes form but stays constant.
• Mass: Total matter remains unchanged in reactions.
• Momentum: Motion is transferred, not lost.