Explore opposites and reciprocals through positive and negative numbers and fractions.

This website explains and defines basic subtraction. There are practice problems at the very end of this lesson.

With the help of simple, teacher-led demonstration activities, students learn the basic concepts of heat transfer by means of conduction, convection, and radiation. Students then apply these concepts as they work in teams to solve two...

Supernovae are divided into two basic physical types, including a description of supernova types and how they are classified based on the existence of hydrogen spectral lines. Definitions of key terms are provided.

The goal of this "visual sourcebook" is to add to the material teachers can use to help theirstudents understand Chinese history, culture, and society. It was not designed to standalone; we assume that teachers who use it will also...

A basic definition of OSI (Open Systems Interconnection), the standard reference model for transferring information from one point in a network to another. Link on the first line of the article to an illustration of the OSI Reference Model.