The telephone and the electric wires when are connected in summer between the two poles, they are kept loose so that they may not break when they contact in winter. on the other hand , if the wires are connected in winter between the two poles, they are kept tight because they will expand in summer and will sag.
The wooden wheels of a bullock-cart are fitted with a iron tyres. To ensure a tight fit, the tyre is made slightly smaller in diameter than the wheel. the tyre is first heated due to which it expands. The heated tyre is then fitted on the wheel. When the tyre cools, it contracts and make a tight fit on the wheel.
The cement floor is not laid out in piece, otherwise it would crack due to expansion in summer and contraction in winter.On the other hand, the floor is laid in small pieces with gaps in between to allow for the expansion during summer. However, glass strips can be placed in the gaps.