Discuss that our earth has a magnetosphere that protects it from the sun, but when solar wind interacts with it, electrons form in the earth's atmosphere near the North and South Poles. Inform them that this makes atomic elements, such as oxygen and nitrogen, glow red, green and even purple and is what causes the Northern Lights.
Use magnets to explain the science behind the Northern Lights. Demonstrate magnetism by having your children create their own compass. Fill a bowl with water and wipe a T-pin along a magnet, such as one on your refrigerator, 25 times. Insert the T-pin partially into a cork from a wine bottle. Place the corked pin in the water and watch it rotate so it lines up along the earth's north-south axis. Use this exercise to help your children understand the concept of a magnetic field surrounding the earth.
Show pictures of auroras that you find online or in encyclopedias and science books. Ask your children questions from the information you just reviewed, such as where auroras occur, what causes them to happen and how their colors are made.