In this colorful and interactive object, learners examine the structure and function of muscle and connective tissues. A quiz completes the activity.

In this brief object, learners examine the direct relationship between the volume of a gas sample and the number of moles of gas. A problem is presented so students can test their knowledge of Avogadro's Law.

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 follow a four-step process to determine the empirical formula of a compound from the masses of its constituent elements. The molecular formula is determined in a fifth step using the molecular weight of the compound.

The definition of an isotope is illustrated using the three isotopes of carbon. The three isotopes of hydrogen are discussed as exceptions.

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

Learners complete an exercise to match chemical formulas with the names of binary compounds, tertiary compounds, and ions.

Learners examine the meaning of theoretical yield, actual yield, and percent yield. They test their knowledge by solving two problems.

In this interactive object, learners identify a person's regional body parts.

Learners view movie clips to determine the solubility of two ionic compounds. They also examine a solubility chart and predict the solubility of compounds.

In this interactive object, learners examine how to properly dilute hydrochloric acid.

In this interactive and animated object, students distribute the valence electrons in simple covalent molecules with one central atom. Six rules are followed to show the bonding and nonbonding electrons in Lewis dot structures. The process is well illustrated with eight worked examples and two interactive practice problems.

Learners calculate gas density from the standard molar volume and observe how the density increases with the increasing molecular weight of the gas.

In this interactive and animated object, learners use solubility rules to predict when an insoluble ionic compound will precipitate in a double replacement reaction. Four step-by-step examples are given.

In this learning activity you'll observe two vehicles moving across the screen at different rates then describe the motion. Additionally, you'll select the corresponding graphs of distance vs. time, velocity vs. time, and acceleration vs. time for each vehicle.

Equilibrium plays a vital role in our lives. We'll show you how the equilibrium formula works in real life using our friend the chicken.

In this animated object, learners view hydrogen and hydroxide ions in a solution. A brief quiz on the basic principles of the term pH completes the activity.

Learners read how microbes in such items as yogurt, bread, insulin, and insect sprays improve our lives.

Students read about the basic organization and structure of the periodic table of elements. By clicking on the symbol, they can read that element's atomic number and weight. In an exercise, students identify elements as belonging to a group, a period, or neither.

In this animated and interactive object, learners examine ABO blood antigens and Rh antigens and their compatibility.

In this animated activity, learners examine hearing and balance. Detailed drawings of the outer, middle, and inner ear structures are included.