Did you know?

The horizontal fraction bar was introduced by the Arabs.

Did you know?

The familiar sounds of your heart are made by the heart's valves as they open and close.

Did you know?

Thyroid conditions cause a higher risk of fibromyalgia and chronic fatigue syndrome.

Did you know?

Lower drug doses for elderly patients should be used first, with titrations of the dose as tolerated to prevent unwanted drug-related pharmacodynamic effects.

Did you know?

Although the Roman numeral for the number 4 has always been taught to have been "IV," according to historians, the ancient Romans probably used "IIII" most of the time. This is partially backed up by the fact that early grandfather clocks displayed IIII for the number 4 instead of IV. Early clockmakers apparently thought that the IIII balanced out the VIII (used for the number 8) on the clock face and that it just looked better.

For a complete list of videos, visit our video library