As a pendulum swings, the amounts of potential and kinetic energy change. does the amount of mechanical energy change?

No, the mechanical energy does not change if it is ideal.

We define mechanical energy as the sum of kinetic energy and potential energy

ME = PE + KE

When the pendulum swings, potential energy is converted to kinetic energy and vise versa. But the sum of both remains constant, which is the mechanical energy.

the aurora is formed when charged particles emitted from the sun during a solar flare penetrate the earth's magnetic shield and collide with atoms and molecules in our atmosphere. these collisions result in countless little bursts of light, called photons, which make up the aurora.

auroras are generated by charged solar particles hitting molecules in earth's atmosphere. this usually happens in high latitudes, because our planet’s magnetic field tends to funnel these particles toward the poles. that’s why it can be experienced in northern ohio.