Free fireworks aren’t as hard to come by as they used to be, due to a law passed in 2017 that allows Pennsylvanians to buy Roman candles, bottle rockets, mortars, aerial shells, and firecrackers. But nothing compares to a full-on fireworks show — the kind that makes so much noise, you can feel the sound waves. Most of the shows take place on the Fourth of July, but some start as early as this weekend (at Penn’s Landing) and go all summer (in Wildwood).