It makes sense that a balloon filled with a lightweight gas such as helium would float when surrounded by heavier air. But why does filling a huge balloon with hot air also make it float? This ...
Students will be able to explain that the density of a substance has to do with how heavy it is compared to the size of the object. Students will also be able to explain that density is a ...
Researchers have found a way to make ordinary aluminum tubes float indefinitely, even when submerged for long periods or ...