What do banks do with money we deposit?

Well, the bank primarily does two things: loan the money we put into the bank, and pay interest annually to your account. The interest is basically to say: since we are loaning your money to other people, we'll pay (and this is just an example) 10% interest of what you put in your bank account.

the causes of the dust bowls were severe droughts,   lands became dry and hard, temperature was higher than usual, hot and dry conditions killed crops, high winds. because of those factors, the winds kicked up dry soil and created clouds of dust.