For more than a century, schoolbook physics has divided matter into neat categories like solid, liquid, gas, and plasma. A ...

Conduct investigations to identify characteristics of gases, and learn about the gases that make up our atmosphere. Explore features of solids, liquids, and gases while noticing that substances can ...

THE tenets of physics can seem carved in stone. The speed of light is a constant. There are four fundamental forces. Theoretically, rules like these are open to revision. But new contenders had better ...