CK-12 Foundation
Ck 12: Life Science: Fermentation
[Free Registration/Login may be required to access all resource tools.] Sometimes cells need to obtain energy from sugar, but there is no oxygen present to complete cellular respiration. In this situation, cellular respiration can be...
CK-12 Foundation
Ck 12: Life Science: Cell Transport
[Free Registration/Login may be required to access all resource tools.] Cells are found in all different types of environments, and these environments are constantly changing. For example, one-celled organisms, like bacteria, can be...
CK-12 Foundation
Ck 12: Scientific Method (Basic)
[Free Registration/Login may be required to access all resource tools.] This is a basic introduction to the scientifice method that includes links to instructional videos, grade-level texts, interactive activities, and review materials.
CK-12 Foundation
Ck 12: Earth Science: Soil Erosion
[Free Registration/Login may be required to access all resource tools.] How human activities cause soil erosion.
CK-12 Foundation
Ck 12: Life Science: Bacteria in the Digestive System
[Free Registration/Login may be required to access all resource tools.] Yogurt is a good source of calcium. Yogurt also contains active cultures of "good" bacteria. Foods that contain these beneficial bacteria are sometimes called...
CK-12 Foundation
Ck 12: Life Science: Hearing and Balance
[Free Registration/Login may be required to access all resource tools.] What do listening to music and riding a bike have in common? It might surprise you to learn that both activities depend on your ears. The ears do more than just...
CK-12 Foundation
Ck 12: Life Science: Passive Transport
[Free Registration/Login may be required to access all resource tools.] The cell membrane is semi-permeable. Sometimes molecules need the help of special transport proteins or an input of energy to help them move across it. When an input...