curling and sweeping

I've been corresponding with one of my nieces about the Beatles film Help! and it reminds me of the first time I saw the sport of curling. It's still a rather obscure sport here in the States, but I have a better idea of it now having watched it during the Olympics.

My first exposure to curling was the film Help! and if you are familiar with the curling scene, you can imagine how silly it looked! And that's without the added [spoiler alert] part about replacing one of the curling stones with a bomb. I remember wondering especially what all the sweeping with brooms was all about. What the heck are they doing? They're sweeping ice for gosh sakes! And what are they doing sweeping near the sliding whatchamacallits for? What's with that? This makes no sense!