11.29 What is Energy Conservation
Learn about energy conservation, what it means, and why conserving energy is a good practice. Discover how energy is used in the United States and how individuals can conserve energy in their daily lives.
9.30 Carbon Dating
Did you ever wonder how scientists know a fossil is 10,000 years old or a piece of paper is 2,000 years old? They use a method called carbon dating. In this lesson you'll learn about carbon dating and how it works.
9.29 Stalactites & Stalagmites
Some caves have cool-looking formations called stalactites and stalagmites. Although they grow in different directions and may be different sizes and shapes, they are all formed by the same basic process. In this lesson, you will learn about these formations.
3.29 The Respiratory System
Learn about the respiratory system, the system of organs and structures in the body responsible for breathing. Discover the parts of the respiratory system and how the trachea, lungs, alveoli, and other parts work together in the breathing process.
3.28 The Muscular System
The muscular system protects the body and is responsible for the body's movement. Explore the muscular system, and learn about the three types of muscles, such as the skeletal muscles, smooth muscles, and cardiac muscles.
1.29 Dependent Variable55
Dependent variables are one of three types of variables used in scientific experiments. Learn about the difference between dependent, independent, and control variables, and see how variables interact in an example of an experiment.