Problem

You need to make knobs on your site immediately obvious.

Solution

Use a consistent style of knobs.

Discussion

There are many styles of knobs, but the best designs are reminiscent of real-life knobs and switches, are convenient to use, and are similar to other widgets used on the site. Successful styles include brightly colored gum drops and embossed blocks.

Sometimes, the knob should take the form of an object. For example, the visitor might move a rocket up and down, to see how the strength of gravity changes with distance from the earth. In such a case, the knob is not self-evident, and it must be clearly indicated, “drag the rocket to different heights” or “change the position of the rocket.” Consider using false color to highlight the icon.