Category Units

Our own units to inspire investigation, develop research skills, and encourage independent learning. Units make it easy to learn together as a family, dig in deep, and spur individual interests.

The Vacuum Tube: A Unit Study

The Vacuum Tube: A Unit Study

On October 20, 1906, the American Lee De Forest demonstrated what is now called a triode, a type of vacuum tube. This device opened the way to practical radio communications and led to the invention of the transistor. How the…