We all like games that have realistic effects and actions. In this chapter we will learn about the ways to make our games more realistic. Have you ever wondered how to provide realistic effect to game objects? It is physics that provides a realistic effect to the games and their characters. In this chapter, we will learn how to use physics in our games.

While developing the game using SpriteKit, you will need to change the world of your game frequently. The world is the main object in the game that holds all the other game objects and physics simulations. We can also update the gravity of the gaming world according to our need. The default world gravity is 9.8, which is also the earth's gravity, World gravity makes all bodies fall down to the ground as soon as they are created.

More about SpriteKit can be explored using the following link:

https://developer.apple.com/library/ios/documentation/GraphicsAnimation/Conceptual/SpriteKit_PG/Physics/Physics.html...