Scientist Nina and her young experimenters discover the amazing ways that things can change and react in our everyday world. Nina investigates why boats float with the help of Luke, her sight neuron. Experimenters Harvey and Sonny visit Nina in her lab and test whether different things float or sink. Using their senses, they discover that things can weigh different amounts if they are made from different things, even if they look the same shape and size. Then they visit a big heavy ferry boat, floating in the sea. Below decks, they discover that the boat is hollow inside and full of air. Finally, back in the lab, they prove that hollow things are more likely to float than solid things, even if the hollow things feel heavier!