Simplify the following text for a Grade 9 native English-speaking person.
Original: It is thinner than continental crust , or sial , generally less than 10 kilometers thick , however it is more dense , having a mean density of about 3.3 g\/cm3 .
Simplified: It is thinner than continental crust , or sial , generally less than 10 kilometers thick , however it is denser , having a mean density of about 3.3 grams per cubic centimeter .