How Does The Fan Work?

The Fan is an electronic device that everybody use it in their house. People use the fan to make the air in the room cooler, especially in hot day. And how does the fan work?
An electric fan is an electric motor with some fan blades attached to its rotating shaft. As the motor spins, the fan blades rotate. Each blade is angled a bit, and as the inclined plane of the blade moves through the air, it forces the air ahead of it forward. Each blade does this on a continuous basis, and the result is a moving air stream. The fan is taking air from the area behind itself and blowing it out the front. 
The fan generates a movement of air, causing the warm dense air to descend, and the cool dense air to rise, thus creating a feeling of coolness in the air.
How a Spider’s Web Forms
A Spider web looks delicate but it is very strong. It can hold 4000 times a spider’s weight. But how does it form.
First the spider spins a thread of silk. The thread gets blown over to a branch by teh wind. Then she makes another two threads and makes a Y shape. Next she makes more threads and they look like spokes off a wheel. Then the spider goes in a spiral, out and back in, sits in the middle and waits for food.
This is how a web is formed.