The idea of energy conservation means that in a closed system, the total amount of energy stays the same.

For mechanical energy, which includes two main types—kinetic energy and potential energy—here's what you should know:

• Kinetic Energy (KE): This is the energy of something that is moving. You can find it using the formula: $KE = \frac{1}{2}mv^2$ Where m is the mass (how heavy something is) and v is the speed (how fast something is going).

• Potential Energy (PE): This is the energy that is stored. A common type of potential energy is gravitational energy, which is related to how high something is. You can calculate it using the formula: $PE = mgh$ Here, h represents the height from a certain starting point.

In a closed system, like a swinging pendulum, the total mechanical energy (which is the sum of KE and PE) stays the same. As the pendulum moves, it changes from potential energy to kinetic energy and back again.

This back-and-forth movement shows us how energy is conserved in a fun way!