Electricity A If electricity hadn't been discovered people would probably still be using candles or gaslights. Thomas E developed the first incandescent on electric light bulb in 1879. Penicillin A If Dr. Alexander Fleming hadn't discovered penicillin in 1928, millions of people would have died from infections. However, the widespread use of penicillin as an antibiotic did not begin until the 1940s, during World War II.