Using much and many is very confusing. Many Americans are confused too! We will learn how and when to use each word correctly.
Things can be counted. We call them Countable Nouns. Examples: students, books, pencils, dogs, flowers, kites, bananas, cars, apples, teachers, and etc.
Things cannot be counted. We call them Uncountable Nouns. Examples: sugar, dust, water, jam, flour, syrup, salt, coffee, ink, sand, air, money, tea, juice, oil, butter, and etc.
Countable nouns we use many.
Uncountable nouns we use much.
Many more exercises: http://www.agendaweb.org/exercises/grammar/countable-uncountable/many-much