No, toothpaste is not simply a liquid; it's more accurately described as a gel or a sol. While it flows and can be squeezed from a tube like a liquid, its composition includes solid particles suspended within a liquid base. This makes it a complex substance that exhibits properties of both solids and liquids.
Understanding Toothpaste's Composition
Toothpaste is a complex mixture, not a pure liquid. According to Chemistry Stack Exchange, it's classified as a sol: a stable suspension of tiny solid particles within a liquid. When the toothpaste dries, the solid components become more apparent. https://chemistry.stackexchange.com/questions/23899/is-toothpaste-solid-or-liquid
TSA Regulations and Toothpaste
The Transportation Security Administration (TSA) considers toothpaste to be a gel, subject to the 3-1-1 liquids rule for carry-on baggage. https://www.tsa.gov/travel/frequently-asked-questions/liquids-aerosols-and-gels-rule This means you can bring a container of toothpaste no larger than 3.4 ounces (100ml) in your carry-on bag. Larger quantities must be packed in checked luggage. Multiple sources confirm this classification:
- AFAR: "...Since toothpaste is considered a liquid, paste, or gel by the TSA..." https://www.afar.com/magazine/the-tsas-3-1-1-rule-for-liquids-in-carry-on-luggage
- Quora: "TSA considers toothpaste a gel. It confirms to the same rule as liquids." https://www.quora.com/Is-toothpaste-considered-a-liquid-by-TSA
In Summary
While exhibiting liquid-like properties, toothpaste's solid particle suspension categorizes it as a gel or sol, not a pure liquid. For air travel, the TSA's 3-1-1 rule applies, treating it similarly to liquids.
