Earth didn't always have oxygen, so what caused the change that allows humans to live here? Learn about the change in O2 levels throughout geological history through an interactive graph. Each section offers greater detail on the changes...

Take it all the way back! Young scientists discover the changes that took place from the time Earth became solid to present day through an interesting interactive. The resource guides users through key events that have shaped our world...

Chromosomes contain keys to history including links from royalty to Neanderthals. Young scientists learn about Ivan Wallin's research into chromosomes with an animation and videos. Then, the concept connects to mysteries related to...