The Osaka Science Museum (大阪市立科学館, Ōsaka Shiritsu Kagakukan) on Nakanoshima Island has four floors of interactive exhibits and displays. The museum was designed with children in mind and takes visitors through displays on the universe, chemistry, electricity and energy. A science show is held three times a day (in Japanese only).
In addition to the exhibits, the Science Museum has a planetarium with multiple daily shows and an Imax Dome Theater, called "Omnimax", with a rotating selection of Imax films at additional cost. The Imax films are only aired on weekends and national holidays.
The Osaka Science Museum is located on Nakanoshima Island directly adjacent to the National Museum of Art Osaka. Take the Yotsubashi Subway Line to Higobashi Station, from where the museum can be reached in a 5-10 minute walk. Nakanoshima Station on the Keihan Nakanoshima Line is even closer.
Right next to Dotonbori in Osaka.