Why did education become an important topic for reformers in the 1800s

The Industrial Revolution in the mid-1700s made it necessary for people to have the ability to do exactly what we still consider as educational necessity. You should be able to 

1 read well enough to convey messages and understand directions, sometimes complex directions and meanings in those messages. 
2 know some math well enough to measure, cipher numerical problems (add and subtract) and perhaps even project something (daily production of an assembly line, tonnage of freight, etc.) 
3 some basic science and chemistry so you didn't mix hot ashes with explosives or poison your customers because of fundamentally ignorant mistakes. 

This education has taken a finer point in recent years, but it stood well the test of time for about 150 years until science and computers made more education both desirable and practical. 

Because the 1800's were included within the age of enlightenment, individuals during that time period sought to advance human knowledge by using methods such as math, science, and philosophy. (This would be the simple answer, if you want a longer FRQ type answer I could do that too)