What happens to air when it heats up

The molecules in the air begin to move faster and further apart from each other. There is still the same amount of molecules in the air, it has just expanded as it heats up.

Warm air takes up more space than the same amount of cold air, it also weighs less than cold air occupying the same space.

For example, a hot air balloon. Without the heated air, it would't be able to float. 

in addition to spreading humanist ideas, erasmus has contributed to criticism of corruption in the church.

they had the law tat factories that produces smoke cannot be built near residential buildings.

building of proper sewage system was done to ensure that the waste is carried away from the humans so that they do not get diseases from it.

also they built water systems to provide water in those areas which are drought prone.