Until very recently women of the house used the traditional method of washing clothes. The job of washing clothes was thus assigned for one or two days of the week. With the invention of the washing machine, the lady of the house can now wash her clothes daily, without having to store dirt and smelly clothes for a couple of days. A typical washing machine looks like this. It is like a big steel bin. Very much like the tin or brass bins in which our mothers stores rice, wheat, or flour. There is a lid on the top. Inside the tub, there is a wheel that is either attached horizontally to the floor or vertically to the wall. There are two openings one to let the fresh water in and the other to let dirty water out. On one side of the machine, there is a control panel. On it, there are many switches. One of them is the on and off switch. The others are to control the flow of water inside and outside the machine. Some machines have a timer, which controls the duration of the washing, and a water temperature control switch also. One has to put dirty clothes, water, and some detergent inside the tub of the machine and switch it on. After some time the machine through its rotation of the wheel inside the tub cleans the clothes.