《燃烧与灭火》ppt课件

燃烧与灭火人教版五年级《科学》下册物质的燃烧在日常生活中，哪些地方利用了燃烧？可以燃烧的物质利用的例子活动1液化石油气煮饭、炒菜木材、树叶蜡烛照明烧水、取暖锅着火了，赶紧盖上盖子！盖上锅盖就能灭火？√√√√√√×××能够燃烧的物质叫可燃物。可燃物是燃烧的首要条件。用烧杯罩住其中一支燃烧的蜡烛，用自己的话描述发生了什么现象？说明了什么？熄灭的原因活动2【实验现象】【结论】露在空气中的蜡烛一直在燃烧，而烧杯中的蜡烛火焰慢慢变小，最后熄灭了。没有氧气蜡烛就不会燃烧。燃烧需要氧气。燃烧需要一定的温度，即达到可燃物着火点。火柴实验活动3把一根火柴放在铁片上，用酒精灯加热，观察会发生什么现象。这说明什么？【实验现象】把铁片加热一会儿，铁片热了，火柴也被烫热了，它就燃烧起来。【结论】让木炭燃烧得更旺拓展要让炭炉燃烧得更旺，应该从那几个方面考虑？①增大氧气的浓度②增大可燃物与氧气接触的面积可燃物在一个有限的空间内急速燃烧会怎样？jincheng.99114.com/pifa-122/jincheng.99114.com/pifa-101/jincheng.99114.com/pifa-105/jincheng.99114.com/pifa-104/jincheng.99114.com/pifa-107/jincheng.99114.com/pifa-117/jincheng.99114.com/pifa-115/jincheng.99114.com/pifa-116/shuozhou.99114.com/pifa-128/shuozhou.99114.com/pifa-118/shuozhou.99114.com/pifa-125/shuozhou.99114.com/pifa-135/shuozhou.99114.com/pifa-131/shuozhou.99114.com/pifa-106/shuozhou.99114.com/pifa-136/shuozhou.99114.com/pifa-113/shuozhou.99114.com/pifa-140/shuozhou.99114.com/pifa-109/shuozhou.99114.com/pifa-103/shuozhou.99114.com/pifa-137/shuozhou.99114.com/pifa-129/shuozhou.99114.com/pifa-133/shuozhou.99114.com/pifa-124/shuozhou.99114.com/pifa-126/shuozhou.99114.com/pifa-102/shuozhou.99114.com/pifa-127/shuozhou.99114.com/pifa-110/shuozhou.99114.com/pifa-114/shuozhou.99114.com/pifa-119/shuozhou.99114.com/pifa-130/shuozhou.99114.com/pifa-123/shuozhou.99114.com/pifa-122/shuozhou.99114.com/pifa-101/shuozhou.99114.com/pifa-105/shuozhou.99114.com/pifa-104/shuozhou.99114.com/pifa-107/shuozhou.99114.com/pifa-117/shuozhou.99114.com/pifa-115/shuozhou.99114.com/pifa-116/jinzhong.99114.com/pifa-128/jinzhong.99114.com/pifa-118/jinzhong.99114.com/pifa-125/jinzhong.99114.com/pifa-135/jinzhong.99114.com/pifa-131/jinzhong.99114.com/pifa-106/jinzhong.99114.com/pifa-136/jinzhong.99114.com/pifa-113/jinzhong.99114.com/pifa-140/jinzhong.99114.com/pifa-109/jinzhong.99114.com/pifa-103/jinzhong.99114.com/pifa-137/jinzhong.99114.com/pifa-129/jinzhong.99114.com/pifa-133/jinzhong.99114.com/pifa-124/jinzhong.99114.com/pifa-126/jinzhong.99114.com/pifa-102/jinzhong.99114.com/pifa-127/jinzhong.99114.com/pifa-110/jinzhong.99114.com/pifa-114/jinzhong.99114.com/pifa-119/jinzhong.99114.com/pifa-130/jinzhong.99114.com/pifa-123/jinzhong.99114.com/pifa-122/jinzhong.99114.com/pifa-101/jinzhong.99114.com/pifa-105/jinzhong.99114.com/pifa-104/jinzhong.99114.com/pifa-107/jinzhong.99114.com/pifa-117/jinzhong.99114.com/pifa-115/jinzhong.99114.com/pifa-116/yuncheng.99114.com/pifa-128/yuncheng.99114.com/pifa-118/yuncheng.99114.com/pifa-125/yuncheng.99114.com/pifa-135/yuncheng.99114.com/pifa-131/yuncheng.99114.com/pifa-106/yuncheng.99114.com/pifa-136/yuncheng.99114.com/pifa-113/yuncheng.99114.com/pifa-140/yuncheng.99114.com/pifa-109/yuncheng.99114.com/pifa-103/yuncheng.99114.com/pifa-137/yuncheng.99114.com/pifa-129/yuncheng.99114.com/pifa-133/yuncheng.99114.com/pifa-124/yuncheng.99114.com/pifa-126/yuncheng.99114.com/pifa-102/yuncheng.99114.com/pifa-127/yuncheng.99114.com/pifa-110/yuncheng.99114.com/pifa-114/yuncheng.99114.com/pifa-119/yuncheng.99114.com/pifa-130/yuncheng.99114.com/pifa-123/yuncheng.99114.com/pifa-122/yuncheng.99114.com/pifa-101/yuncheng.99114.com/pifa-105/yuncheng.99114.com/pifa-104/yuncheng.99114.com/pifa-107/yuncheng.99114.com/pifa-117/yuncheng.99114.com/pifa-115/同时具备可燃物氧气着火点三个燃烧条件同时具备，则发生燃烧。破坏其一，则燃烧停止。分析P24图，分析人们是通过控制燃烧的哪个条件灭火？灭火的方法讨论1、移走其他的油桶2、断开电源，盖上沙子3、使用灭火器4、用水灭火（可燃物）（氧气）（氧气）（着火点）你能将以下灭火方式分类并归纳出灭火的原理吗？1、“盖棉被”、“沙子”、“喷CO2”——让氧气与可燃物隔离。2、“吹”、‘’湿布”、“扇”——降低温度至着火点以下。3、“搬走木柴”——可以去掉可燃物。灭火——破坏燃烧的条件【日常生活】1、如果炒菜时锅里的油起火，怎么灭火？盖上锅盖，隔绝空气而灭火。2、如果酒精灯不慎撞倒引起酒精在桌上燃烧，应如何灭火？用湿抹布扑盖，这样既可以让可燃物隔绝空气，同时水吸热降低可燃物的温度。3．扑灭森林火灾的有效方法之一，是将大火蔓延线路前的一片树木砍掉。你知道原因吗？清除可燃物。