Many cleaning products, such as soap and oven cleaner,
are bases. Bases neutralize (cancel out) acids. Alkalis are bases that dissolve
in water. Strong bases, such bleach, are corrosive and burn skin. Bases contain
particles called hydroxide ions. The more hydroxide ions a base contains, the
stronger it is.
Limestone is an important base that is dug from the earth in
quarries. It comes from calcium carbonate, which formed millions of years ago
from the compressed remains of sea-shells and other marine life. Once quarried,
limestone is crushed and used to make cement, fertilizers, paints, and
ceramics.
