In this animated object, learners examine the various connective tissue layers of the muscle organ. The terms "prime mover," "synergist," "antagonist," "origin," and "insertion" are defined.

Learners view several movie clips that demonstrate the use of an indicator to follow the neutralization reaction that occurs when an acid and a base are mixed. Students test their knowledge in a series of questions. Immediate feedback is given.

In this interactive object, the learner practices identifying charges on ions.

Students choose the hypothesis and practice describing bacterial colonies using the steps of the scientific method.

Roman numerals are used to identify the charges on metal cations having multiple oxidation states. Five examples are provided for practice.

This learning object demonstrates the process by which antigens are identified, processed, and presented to mediators of the cellular immune system.

In this interactive object, students examine a type of chemical bond known as the "hydrogen bond."

Viewers watch an introduction to monosaccharides, disaccharides, and polysaccharides. The processes for dehydration synthesis and hydrolysis.

Learners examine the periodic table to identify metallic elements that have either fixed or variable oxidation states.

Students examine standard pressure in this interactive object.

Ions are electrically charged particles obtained from an atom or from a chemically bonded group of atoms by adding or removing electrons. Eight examples illustrate the number of protons, neutrons, and electrons in positive ions (cations) and in negative ions (anions).

In this colorful, interactive object, learners examine nervous and epithelial tissue composition and function. A quiz completes the activity.

In this animated and interactive object, learners examine the location, structure, and function of the juxtaglomerular (JG) apparatus.

Learners view an animated presentation showing how the pH level of a cleaning solution is controlled in a closed-loop system in a manufacturing setting. A quiz completes the activity.

Learners observe that the volume of one mole of any gas is 22.4 L at standard temperature and pressure. An illustration shows that only the mass of the molar volume differs with the identity of the gas.

In this screencast, learners read how microbes in such items as yogurt, bread, insulin, and insect sprays improve our lives.

In this well-illustrated object, learners examine the structures and properties of the four types of solids: molecular, metallic, ionic, and covalent network. Five interactive questions are provided.

In this screencast, learners examine the function and location of the motor neurons and the damage that can result when they are injured.

Atomic weights are used to convert the mass of a sample into the number of moles of the element in the sample and vice versa. Four examples are provided for practice.

In this animated object, students examine the role that the solubility of water plays in various biological functions.

In this animated object, learners examine how gas volume varies directly with absolute temperature (K at constant pressure). An example of a sample of gas at two conditions of volume and temperature is used to illustrate the law.

Learners read a description of torque and study the factors that cause its magnitude to change.

Learners study the effect that pressure has on boiling temperatures. Once a liquid has reached a full boil, additional heat does not raise the liquid’s temperature; however, pressure can vary the boiling point of a liquid. A brief quiz completes the activity.

Learners view illustrations showing the direct dependence of the volume of a gas on temperature and consider the relationship between the Kelvin and Celsius temperature scales.

In this screencast, learners examine the steps of carbohydrate digestion.