Tommy and Suzy (brother and sister) went to the playground one afternoon with their mom and dad, Jan and Dean. They were playing a game of tag and having the best time ever running after each other and laughing. They liked to play tag instead of building sandcastles or swinging. They liked tag because they liked to run. They like to play hopscotch or jump rope but that day they wanted to play tag. Other games aren't as fun. They met Tony and Ally (who are best friends) and invited them to play tag too. Tony and Ally like to play other games like hopscotch or jump rope but that day they joined the game of tag. Making new friends is important. Tony and Ally would rather make friends than play their favorite games.

Whom did Tony and Ally make friends within the playground?

What if you could drain all of Earths oceans? What would it look like? You might be really surprised. You see that the surface has two main features. It has continents and ocean basins. Continents are large land areas. These are the areas that are mostly above sea level. Ocean basins extend from the edges of continents. They include the ocean floor and Earths deep ocean trenches. You will also notice the ocean floor is not flat. It too has many Continents are much older than ocean basins. Some rocks on the continents are billions of years old. Ocean basins may only be millions of years old. Because the continents are so old, a lot has happened to them! As we view the land around us, we see landforms. Landforms are physical features on Earths surface. These features change over time, but how? There are actually two types of forces at work.

What are the ages of ocean basins and continents?

You may wonder if there are other examples of static discharge. The answer is yes. Lightning is a form of static discharge. It is much more dramatic than what happens between you and the door knocker, but it is the same principle. You can see how it occurs in the following diagram and animation. You have no doubt seen lightning in a rainstorm. What does lighting have to do with static electricity? As it turns out, everything! During a rainstorm, clouds develop regions of different charges. This happens due to the movement of air molecules, water drops, and ice particles. The negative charges are concentrated at the base of the clouds. The positive charges are concentrated at the top. The negative charges repel electrons on the ground below. The ground then becomes positively charged. Over time the differences increase. Eventually the electrons are discharged. This is what we see as lightning. You can watch an awesome slow-motion lightning strike below.
How does ground become positively charged?