The video explains how elements behave differently in compounds, focusing on fluoride's role in dental health. It recounts the accidental discovery of fluoride's benefits in preventing tooth decay, leading to the fluoridation of water in Grand Rapids, Michigan, in 1945. The video also details how fluoride chemically strengthens tooth enamel by forming fluorapatite, making it more resistant to decay.

What was the initial observation that led to the discovery of fluoride's benefits for dental health?

• Fluoride was used as a cleaning agent.

• Fluoride caused teeth to become brittle.

• Fluoride was found to be a natural sweetener.

• Teeth with brown stains were more resistant to decay.

Which city was the first in the United States to intentionally fluoridate its water supply?

• New York, New York

• Denver, Colorado

• Grand Rapids, Michigan

• Los Angeles, California

By what percentage did the number of cavities drop in Grand Rapids after water fluoridation?

• 60%

• 45%

• 30%

• 75%

What compound in tooth enamel does fluoride interact with to prevent decay?

• Hydroxyapatite

• Calcium carbonate

• Magnesium sulfate

• Sodium chloride

What is the name of the compound formed when fluoride combines with ions in the tooth enamel?

• Calcium fluoride

• Fluorapatite

• Sodium fluoride

• Phosphate fluoride