Photographing Fireworks - Brambleton, VA

So last Saturday my neighborhood had their annual Red, White and Bram (Brambleton) Festival which included a day of concerts, food and fireworks. I decided to experiment and shoot fireworks at different shutter speeds and aperture settings to see what I would get. I didn't have a tripod on me so most of these shots were handheld while leaning the camera against a rail.  These were shot with my Nikon D90.  Can you tell which ones where shot with a slower shutter speed?