The task assigned to engineering students at Johns Hopkins University was to reinvent the leaf blower: maintain its powerful performance while drastically reducing its noise. Their goal was to eliminate the ear-splitting whine that has led to leaf blowers being banned in some areas and widely criticized in others. Surprising their sponsors, advisers, and even themselves, the students succeeded. Their redesigned leaf blower reduces overall noise levels by nearly 40% and virtually eliminates the most grating frequencies. Read on.