When it's raining the only thing to do is go fishing. I prefer to fish with a fly but sometimes use a spinning rod as shown in the photo. This technique involves casting out a shiny metal lure then reeling it back in again. The speed at which you reel in is quite important as it determines the path of the lure through the water, too fast and the lure comes to the surface, too slow and it sinks. I thought I'd investigate this affect with interactive physics so made the simulation below. This is rather simplified as there is no drag from the water however the results are interesting and seem to support the practical results from my fishing trip. Could be a good EE topic for anyone still looking for one.

You may notice a big force acting upwards on the falling mass, this is there to balance the downward force of gravity so the mass falls with constant velocity, simulating reeling in the lure at a constant rate.

I thought that simulation was a bit plain so set about drawing in a fishing rod and some water, I think it looks much nicer now.