The House of Representatives is a 435-member body that meets in the south end of the Capitol building. Its members are chosen from districts apportioned by population - so, for example, California has many more Members than South Dakota, since the former has so many more residents - and are elected every two years. The Constitution specifically provides that the House has the sole power of impeachment, or of legal removal from office of federal officials that have committed "high crimes and misdemeanors," and also directs that any bills that raise revenue must originate in the House.
The Senate, on the other hand, is a 100-member body that meets in the north end of the Capitol building. Each state has two Senators, no matter how large or small the state might be, and Senators are elected for six-year terms. The Constitution directs that the Senate shall conduct impeachment trials, and that it should provide "advice and consent" to Presidential appointments and on treaties. The Senate is designed to be a bit more removed from the popular will than the House, to be, as Washington reportedly put it, the "cooling saucer" to the House's hot teacup.
