1 After an insulator has been electrified, the electricity does not move through the insulator as it would through a conductor.2 These free electrons usually do not move in a regular way.3 Contrary to what is often thought, the earth does not move round in the empty space.4 It is imperative to emphasize that no patient with a marked stridor should be submitted to general anaethesia.5 In general, no new substance forms in a physical change.6 Every machine here is not imported from abroad.7 In the thermal power plant, all the chemical energy of the fuel is not converted into heat.8 Not every collision results in a chemical reaction, since many molecules do not possess the required energy.9 But friction is not always useless, in certain cases it becomes a helpful necessity.10 Both of the substances do not dissolve in water.