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Water is important to all living things but some areas in the world are short of water a lot. So we should try to protect and save water.
A group of students from Zhejiang University have successfully developed an "air hand-washing
Machine". The machine uses an infrared ray induction system（红外线感应系统）, which can feel the presence of our hands. If it feels there are hands, the water with the air will come from the tap. And it has been proven that it is nearly as effective as traditional hand-washing. It uses only ten percent of the water that regular hand-washing does. The students have even set up a company to introduce the product to the public.
Li Qizhang, a member of the team that developed the machine, told a reporter that a model of their machine had already been placed in a classroom building at the university and it worked very well.
In 2014, a student called Chen Puyang first thought of the idea while he was washing his hands. Washing one's hands uses a lot of water, Chen thought. Would it be possible to replace the water with air?Others may not give the question a second thought. However, for Chen and Li, who were studying fluid mechanics（流体力学）at the time, this was considered to be an excellent idea.
Soon, Chen, Li and several classmates started on the project. After a year of research, the team came up with a gravity-driven（重力驱动）hand-washing machine successfully.
