Plutonium (Pu) plays a special role in the exploration of space. It is also used to create energy in nuclear power plants. Despite these useful abilities, plutonium is known to be a highly dangerous and controversial element. It is used to make nuclear weaponry. Exposure to plutonium can make people terminally sick. Despite the dangers, more than 2,000 tons (1,800 metric tons) of the element have been created over the past seventy years. Students learn about Glenn Seaborg, Arthur Wahl, and Joseph Kennedy’s discovery of plutonium for the first time by bombarding uranium-238 with deuterons (a proton and a neutron) in the cyclotron. They also explore plutonium’s place in the actinide series of the periodic table and its radioactivity, its allotropes, compounds, and alloys, and its nuclear applications and dangers.