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 ...

Note: This video is designed to help the teacher better understand the lesson and is NOT intended to be shown to students. It includes observations and conclusions that students are meant to make on ...

Build literacy skills while making predictions with this sink-or-float activity. It's fun to learn about new concepts in a hands-on way. This family does just that with a sink-or-float activity you ...