Physics
Water is not suitable as a calorimetric substance because it :

Is a good conductor
Has high specific heat
Low latent heat of vapourization
Has high boiling point

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Physics
Skating on ice is possible because

The surface of ice is smooth
The pressure on the ice due to skate raises its melting point
Ice is cold
The pressure on the ice due to skate melts the ice by lowering its melting point forming a thin film of water

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