Learners observe how a blood drop in flight continually accelerates and increases in velocity over time. As the drop falls, resistance accumulates. The increase in stain diameter relative to distance of a typical 50 ml drop of blood is represented here. This activity has audio content.

You'll practice calculating the area of a circle given its diameter or radius.

Learners examine the basic types of dimensioning including unidirectional and aligned systems, and linear, aligned, angled, arrowless, chain, datum, chart, tabular, radius, diameter, typical, and reference dimensions.

Learners examine the drawing symbols used for counterbore, countersink, spotface, radius, diameter, and depth. In the quiz that completes the activity, they associate these symbols with machining applications.

You'll practice calculating the circumference of a circle given its diameter or radius.

This project gives a drawing with steps to complete the activity.

In this interactive object, learners examine standard and metric thread specifications used in engineering drawings. In a brief quiz, they identify various internal and external thread representations.

In this interactive object, students explore the basic elements and common terms associated with dimensions and leaders. A quiz completes the activity.

You'll practice defining terms related to spheres and identifing parts of spheres.

Learners practice reading prints of a hub. They identify information located on the print and calculate missing dimensions.

You'll define terms related to circles.

In this animated object, students view an example of how to convert rotational velocity to linear velocity. They then work practice problems.

Learners examine the proper way to set up standard and metric micrometers to measure the wear on a brake drum.

In this animated and interactive object, learners examine the definitions and formulas for radius, diameter, circumference, and area. Students also solve practice problems involving the circumference and area of a circle.

Students examine the four factors that affect resistance of a wire: temperature, length, diameter, and the type of material from which it is made. A short quiz completes the activity.

This video clip shows the outside diameter turning on an engine lathe.

In this animated object, learners examine the concept of gear ratios. The number of teeth, diameters, and velocity relationships are discussed and calculated using linear ratio equations. A quiz completes the activity.

In this interactive object, learners are given the RPM, the pulley diameter, and the force, and proceed to calculate belt velocity and horsepower.