It wasn't easy. First, the crew tried to blow up a watermelon using a smaller capacitor -- one that contained over 1,000 joules of energy. For context, a capacitor of about 200 joules is enough to power a professional camera's flash. A 1,000-joule capacitor is enough to blow a hot dog (or a human heart, the dude in the video mentions with a cocked eyebrow and far too much enthusiasm) to pieces. But once they set it up with a watermelon, even a burst of 1,000 joules wasn't enough to destroy the mighty melon.
So they added more power, building a capacitor bank the size of a small kitchen island with more than 20,000 joules in it. "That's like shooting four .50-caliber sniper rifles at the exact same time," the Backyard Scientist explains. Then they attached a watermelon to it and ran 20,000 volts of electricity through the damn thing. Watch the video to see what happens. Words don't really do it justice, but a neighbor did threaten to call the cops.