What happened to Homer's bag of "rocket stuff" in October Sky?

Homer (Sonny) gets in a tussle with some boys (Calvin, Pooky's son). The boys just want to talk to Sonny, but he thinks they want to beat him up. There is a flood and Sonny has his rocket nozzles and nose cones in a sack. During the tussle, he drops the sack and loses it in the swirling, muddy water. Sonny thinks that he will never find his "rocket stuff" now. Calvin promises that when the waters go down, he and his friends will help Sonny look for the items, but Sonny replies that by then, it will be too late. He needs them for the science fair. The next morning, Sonny finds a wet sack on the back porch. In the sack are the nozzles and nose cones. Apparently Calvin and his friends looked for the sack, found it and returned it to Sonny.

What happened to Homer's rocket display in October Sky?

Homer and Tex went back to the hotel after the first day and had a good night, Homer remarked about the odd sensation of walking around Indianapolis and how busy it was, not just with traffic, etc., but also about how flat it was.  The absence of the mountains was very strange to him.

After they went back to the convention hall in the morning, it was the absence of everything in his display that was of far greater concern.  Apparently everyone locked up their gadgets overnight but no one told Homer so someone had come through and taken everything in his display.

Luckily they are able to get replacements for most things sent from home by bus after some serious work by the guys at the mine.

What serious event happened to Homer in October Sky?

About a week after they'd exposed their first pipe, the boys had really gotten good at harvesting the scrap iron and had quite a pile of it built up, Homer described it as being nearly as tall as their tent.  At one point, Homer slips and when he puts his hand back to catch himself, it goes into a pile of this scrap iron and it cuts him.  He doesn't realize at first how severe it is until the blood is gushing out and they realize that it has severed his artery.  Luckily the boys are smart enough to apply a tourniquet which ends up saving him from bleeding to death and he is patched up by the Doc and allowed to go home.