Energy
The core of the sun is like a giant, continuously-exploding hydrogen bomb. Every second, five million tons of hydrogen is converted straight into energy—far more energy in a second than humans have used in 10,000 years! That energy starts out at millions of degrees as it crawls out to the surface. By the time it gets there it has fallen to 6000 °C. That's still hot enough that atoms are torn apart into a sea of particles called plasma. The plasma is electrically charged, and generates a ferocious magnetic field. The magnetic field lifts searingly-hot, twisted ropes of plasma off the surface, and when they finally get too high and snap, they spray plasma in all directions: a solar flare.
Star
As complex and dynamic as our sun is, it is actually quite stable and ordinary compared to other stars. It only looks like the largest star there is because it is the closest. In fact, almost all of the stars you can see in the night sky are larger than the sun. That doesn't mean it is a small star though. It is above average, but you need a telescope to see all the dwarf stars that are smaller.
Solar Power
Almost everything on Earth is powered by the sun's energy. Plants absorb and store it, and animals eat them to get what they need. Sometimes an organism's energy can be concentrated underground after it dies, and we call it coal or oil. The sun also evaporates ocean water and warms the air driving the weather, which, in turn, powers rivers. Cars, people, and appliances are all solar powered! Only five hundred-millionths of one percent of the sun's energy hits Earth, but that amount is still more than we could possibly use.
