7 Drilling for fire钻木取火 Collect information on the use of fire by ancient people and learn how to drill wood for fire.搜集有关古人利用火的资料,了解钻木取火的方法。 Prepare the following materials: wooden boards, sandpaper, wire, hand drill, matches, etc.准备以下材料:木板、砂纸、铁丝、手钻、火柴等。 Try to explain how the ancient people drilled wood to make fire by using the idea of energy transformation.试用能量转化的观点解释古人钻木取火的道理。 I think that friction produces heat.我认为摩擦会产生热量 This is how energy is transformed...能量是这样转化的… Let's do something to test our guesses动手做一做,验证我们的猜想 How to make fire by drilling wood钻木取火的道理 I have other ways,我还有其他方法, The transformation of mechanical energy into heat energy in life生活中机械能转化成热能的现象 The phenomenon of energy conversion can sometimes have a negative impact on our lives, what can we do about it?能量转化现象有时会给我们的生活带来不利影响,怎么办呢? High-speed cars are prone to flat tires高速行驶的汽车容易爆胎 When a hand drill is working, the drill bit gets very hot.手钻工作时,钻头会很热。 I know...我知道… What else can mechanical energy be converted into?机械能还能转化成什么能? In ancient times, people used to obtain fire by drilling wood, using fire scythes and flints, and using flint to obtain fire (a concave mirror to gather sunlight to obtain fire).古人利用钻木取火、火镰和火石取火、阳燧取火(凹面镜聚集太阳光取火)等方法获取火种。 Fire was the first natural force that human beings utilized.火是人类最早利用的自然力。 The use of fire announced the end of mankind's history of drinking blood and was a great step forward in the march of civilization.火的使用宣告了人类茹毛饮血历史的结束,是人类在文明的征途上迈进的一大步。 Look up the information and learn more about the methods and history of fire in ancient times.查阅资料,详细了解古代人用火的方法和历史。 |
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