Physics
A solid needle placed horizontally on the surface of the water floats due to

Viscosity of water
Surface tension of water
Capillary action
Water pressure

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Physics
Lightning is produced when

Clouds strike against impurities in air and the friction burns up these impurities
Similar charges of electricity rush towards each other and then get repelled
Water vapour produces electricity in the clouds
Strong opposite charges in different clouds break down the resistance offered by the intervening air

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