Why did nazi Germany bomb Britain?

Following the retreat of the British and other allied forces from Dunkirk the Germans (Hitler etc.) felt they could overtake the British mainland as they had the Continental countries, by similar blitzkrieg tactics, Because the British channel stood in the way of invasion by land forces the Germans thought they could soften up the UK population by indiscriminate bombing. In the first fifteen months from the start of bombing 40,000 people were killed and by the end of hostilities a total of 60,000 had died. The RAF in the period called the Battle of Britain caused such a high casualty rate in German personnel and aircraft they were forced to restrict their subsequent activities. This of course was well before the US entered the war ! Hieler can't occupy England ,so he want use bomb let England submit