A 3-way bulb contains two filaments, and these filaments have differing wattages. Depending on the setting, the filaments operate separately or together to create the appropriate amount of light. Learn more about 3-way bulbs in this HowStuffWorks podcast.
Learn more about your ad-choices at https://www.iheartpodcastnetwork.com

BrainStuff Classics: How Did Alchemy Create Chemistry?
07:11

How Did Sundown Towns Say the Quiet Part Out Loud?
11:35

Why Do We Yawn, and Why Is It Catching?
12:02