Planes and small submarines attacked Pearl Harbor at 7:51 a.m. on Sunday, December 7, 1941. They chose this time because most people were at church. At 08:30, a second wave of 170 Japanese aircraft, mostly torpedo bombers, attacked the fleet anchored in Pearl Harbor. The battleship Arizona was hit with an armor-piercing bomb which penetrated the forward ammunition compartment, blowing the ship apart and sinking it within seconds.
Overall, nine ships of the U.S. fleet were sunk and 21 ships were severely damaged. Three of the 21 would be irreparable. The overall death toll reached 2,350, including 68 civilians, and 1,178 injured. Of the military personnel lost at Pearl Harbor, 1,177 were from the Arizona.
Japan attacked because they thought they could take over the pacific islands, and if they attacked Pearl Harbor we would give up Hawaii.
Before the attack we stayed out of the problems with Germany and Japan but after the attack, we decided to declare war.