In this animated object, learners examine how a gateway server operates.

In this interactive lesson, learners study examples of the expressions "a few" and "a little" with count and noncount nouns. They practice using these expressions in a drag-and-drop exercise of 20 sentences.

This animated lesson shows how a ladder circuit causes the cylinder of a hydraulic circuit to continuously extend and retract after a Start button has been pressed.

This animated lesson shows how a pressure switch connected in a ladder circuit causes the cylinder of a hydraulic circuit to extend and retract.

This lesson provides a drawing with steps to complete the activity.

In this animated lesson, the learner examines how a ladder circuit causes the cylinder of a hydraulic circuit to make a single extension and retraction.

Students match images of insects and other pests with their descriptions in this lesson on keeping a food service operation free from contamination.

This animated lesson shows how pushing a start or stop button on a ladder circuit causes the cylinder of a hydraulic circuit to extend and retract.

Learners read about the vector diagram for a parallel RL circuit. This animated lesson presents information on current flow through each branch, total current, and phase angle.

In this interactive lesson, students examine the quantitative relationship between chemicals in a balanced mathematical equation.

In this interactive lesson, learners study the use of "many" and "much" with nouns that can be counted and nouns that cannot. They then practice using these words in a drag-and-drop exercise.

Learners read about the vector diagram for a parallel RC circuit. This animated lesson presents information on current flow through each branch, total current, and phase angle.

In this interactive lesson, learners read and hear instructions for sending an e-mail. Steps are given for composing an e-mail message and for sending it. Students have an opportunity to write their own messages. A quiz follows the instruction.

This animated lesson shows the operation and characteristics of thru-beam optical sensors.

In this animated activity, learners view the flip-flop and read about its outputs, the information it stores, and its storage conditions. A quiz completes the lesson.

In this animated lesson, students view the operation of an electromechanical relay. A brief quiz concludes the activity.

In this animated lesson, students read how reducing the thickness of a food is an important factor in cooling it. They also read FDA guidelines for food temperatures.

Users examine ways for students to give feedback to their instructor about what they have learned and what part of the lesson is not clear.

Students add suffixes to base words to form nouns in this interactive lesson.

In this animated activity, students view a step-by-step approach for how to connect an ammeter to a circuit. A brief quiz concludes the lesson.