Answers

2015-02-10T18:34:24+05:30
U can make models on rainwater harvesting , volcano , thermal power plant..!! 

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2015-02-10T18:36:44+05:30
You could make an fire alarm you would need a board a resistent a transistor a capiciter a buzzer and a sensor firstly attach the resistent transitor and capiciter to the board and then attach there sensor buzzer and battery
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