In our solar system the planets revolve around the sun or "orbit" the sun. For all practical purposes the sun is in a "fixed" position or in other words, stays in the same place. Not only are we orbiting the sun, the earth also rotates or spins on its axis (like if you spun a basketball around). Because the earth is "spinning" and the sun is fixed, sunlight only strikes the side of the earth that is facing the sun. As we turn or spin (from left to right) we see the sun come into view (east or morning) and as we continue to spin we see the sun leaving our view (west or evening). To help you see what happens try this; shine a flashlight on a ball or globe. As you turn the ball or globe you will see the light shines on a different part as you turn it. Pretend the flashlight is the sun (fixed) and the ball is the earth (spinning) and you'll get the idea.
Why the sun rises in the east?
It's due to the direction of the rotation of the Earth. If you were looking down on the solar system from "north" of the Sun, the Earth would be spinning anti-clockwise, so at any given point on the planet it seems that the Sun is appearing from the East.
Because the earth spins in space (like a ball) in an anti-clockwise direction. Put a dot on a tennis ball and spin it anti-clockwise, relative to the room light and you will see the dot go into shade (night) and then light (day). The dot is you; the sun doesn't move relative to you -- you are doing the moving.
