[Free Registration/Login may be required to access all resource tools.] Ever notice blue-green mold growing on a loaf of bread? Do you like your pizza with mushrooms? Has a physician ever prescribed an antibiotic for you? Learn more...

[Free Registration/Login may be required to access all resource tools.] What does the heart look like? How does it pump blood? Learn more about the heart in this learning module produced by CK-12.

[Free Registration/Login may be required to access all resource tools.] Sperm, the male reproductive cells, are tiny. In fact, they are the smallest cells in the human body. Some people think that they look like tadpoles. Learn more...

[Free Registration/Login may be required to access all resource tools.] Overview of the different colors in visible light and how they relate to its wavelength, how a prism separates visible light into its different colors, the colors of...

[Free Registration/Login may be required to access all resource tools.] Definition of a lever and the three different classes, and how each one changes force.

[Free Registration/Login may be required to access all resource tools.] Visible light and the different waves that make it up, infrared light and ultraviolet light.

[Free Registration/Login may be required to access all resource tools.] Power and how it relates to work and time, how to calculate power and the unit called horsepower.

[Free Registration/Login may be required to access all resource tools.] What a screw is, how it works and its mechanical advantage.

[Free Registration/Login may be required to access all resource tools.] Definition of speed and its SI unit, instantaneous speed and how to calculate average speed and distance or time from speed.

[Free Registration/Login may be required to access all resource tools.] What a wedge is and its mechanical advantage, how it changes force to make work easier.

[Free Registration/Login may be required to access all resource tools.] Humans are in the same domain as trees and algae. What could they possibly have in common? It is the location of their DNA inside their cells. Their cells all have a...

[Free Registration/Login may be required to access all resource tools.] As you age, you might start noticing pain in your knees or elbows. These are examples of joints. Joints are the part of the skeletal system that connect your bones....

[Free Registration/Login may be required to access all resource tools.] Discusses the definition of energy, the SI unit, and the seven different forms of energy.

[Free Registration/Login may be required to access all resource tools.] What a lens is and what it does, concave and convex lenses.

[Free Registration/Login may be required to access all resource tools.] Definition of weight and how to calculate the weight of an object.

[Free Registration/Login may be required to access all resource tools.] What an acid is and its properties and uses. How to detect and measure the strength of acids.

[Free Registration/Login may be required to access all resource tools.] What a base is and its properties and uses. How to detect and measure the strength of bases.

[Free Registration/Login may be required to access all resource tools.] What a pulley is and the three basic types, and the mechanical advantage of a pulley.

[Free Registration/Login may be required to access all resource tools.] X-rays and their uses, xrays as high-energy rays and their dangers.

[Free Registration/Login may be required to access all resource tools.] Aquatic biomes can be generally classified based on the amount of salt in the water. Freshwater biomes have less than 1% salt and are typical of ponds and lakes,...

[Free Registration/Login may be required to access all resource tools.] HIV, or human immunodeficiency virus, causes AIDS. AIDS stands for "acquired immune deficiency syndrome." It is a condition that causes death and does not have a...

[Free Registration/Login may be required to access all resource tools.] Insects, with over a million described species, are the most diverse group of animals on Earth. They may be found in nearly all environments on the planet. No matter...

[Free Registration/Login may be required to access all resource tools.] The kidneys are important organs in maintaining homeostasis, the ability of the body to maintain a stable internal environment despite a changing environment....

[Free Registration/Login may be required to access all resource tools.] During mitosis, the DNA in a nucleus must replicate. The copied DNA is divided into two genetically identical sets, so that after cytokinesis or cell division, each...