What are e-cigarettes?

E-cigarettes are battery powered vaporizers originally used to inhale liquid nicotine. 
Inside of an E-cigarette is a battery that heats the liquid, which then produces "vapor"
These "vapors" are actually, aerosol! In other words...when your inhaling aerosol you are essentially inhaling hairspray (which is an aerosol). So, what is the difference between the two?
Vapor is a liquid that becomes a gas, whereas aerosol is a liquid that remains a liquid in tiny droplet form. 

Since they were first invented in 2003, E-cigarettes have evolved over the years. They used to look like real cigarettes called cig-a-like. These early E-cigarettes were disposable after a one time use.  When they started to gain popularity they morphed into different variations like vape pens, mods, and pod-based e-cigarettes (like Juul). As they morphed, E-cigarettes became more convenient and appealing for young users . This birthed the rechargeable and refillable models used today. They are even sold now to look like everyday items like USB's to normalize the use of these products & help disguise them when using in school and work.

Resources for this article are in part by the CDC, FDA and the NHIS