Here's why:
* Sunlight contains all colors: Sunlight is a mixture of all the colors of the rainbow.
* Prisms bend light: A prism bends different colors of light at slightly different angles. This is called refraction.
* Separation of colors: Because of this difference in bending, the colors in sunlight are separated, creating a continuous band of colors, from red to violet.
Let me know if you have any other questions!