Final answer:
Elements heavier than uranium are created in particle accelerators or nuclear reactors by bombarding target nuclei, leading to the synthesis of transuranium elements.
Step-by-step explanation:
Scientists create elements heavier than uranium using machines known as particle accelerators or nuclear reactors. In these machines, target nuclei are bombarded with smaller particles, such as neutrons or more massive nuclei. This process results in the creation of transuranium elements, which are those with atomic numbers greater than 92, the atomic number of uranium. For instance, neptunium (element 93) was the first of these to be synthesized in 1940 by bombarding uranium-238 with neutrons, leading to a chain of reactions that resulted in its creation.