Why does magnetic declination change over the years

The angle between the direction of force and the direction of the geographic north pole is called the declination. As the earth's magnetic field varies over time, the positions of the north and south magnetic poles gradually change. The magnetic declination at a given location also changes over time.

You would be correct, boiling water does disinfect contamination.    the property of disinfecting means to kill  germs, bacteria and other pathogens or contamination  that might cause an infection or cause a person to become sickly. a couple methods of disinfecting are using soap, other cleaning supplies or by simply "boiling" the contaminate.  the reason why boiling water disinfects certain attributes is because some cells cannot survive the heat and pressure.

Ais stronge