Washoe County Library System

Sixty-six million years ago, an object the size of a city descended from space to crash into Earth, creating a devastating cataclysm that killed off the dinosaurs, along with three-quarters of the other species on the planet. What was its origin? Lisa Randall proposes it was a comet that was dislodged from its orbit as the Solar System passed through a disk of dark matter embedded in the Milky Way. In a sense, it might have been dark matter that killed...

In simple text, presents the three states of matter, solid, liquid, and gas, and describes their attributes.

Investigate the amazing world of physical science and find out for yourself about solids, liquids, and gases through experiments that you can do at home.

Students working on a science project learn about atoms and molecules, the states of matter and how they change, and the differences between mass, volume and density.

Examines the properties of matter, discussing the different states, densities, and making new kinds of matter.