Mathematics Stainless Steel Vacuum Flask
Here's a flask to fuel your next mathematic breakthrough. It'll keep your coffee steaming hot throughout the longest of problem sets and most complicated proofs.
Volume: 18 ounces
Opening: Wide Mouth
Material: High-grade stainless steel
Cap Material: BPA-Free Plastic
Care: Hand Wash (do not wash in dishwasher)
Fill it with your favorite mulled hot cider or cold brew, and even if you don't get around to drinking it for hours, you can expect to find your beverage ready and waiting for you at the right temperature. The BPA-free flip cap seals tightly, so it won't leak all over your bag, and you don't have to take the lid off in order to enjoy your drink.
Here's how it works: the space between the inner and outer flask wall is evacuated, creating a vacuum (well, a partial vacuum anyway...). In order for heat transfer to take place from the outside world into your cold drink, or from your hot drink to the outside world, it needs nearby molecules to excite. If there aren't many molecules nearby, as is the case in a vacuum, the heat's energy can't easily be passed along, so your drink stays close to the temperature it was when you put it into the flask for a really long time.
Simply stated, vacuums make great thermal insulation!
I work on a vegetable farm where cold water is hard to come by while you’re working the fields in the middle of summer. When it’s in the shade, it keeps my drinks NICE and cold - as if they were just in the fridge! I’ve left it in the sun for a few hours before, and even then the water was still drinkable. Not cold, but certainly not hot either! Worth every penny. Plus, the bright yellow color makes it easier to spot in the fields!
The design is very cool and the bottle just looks nice. Nothing misleading in the description, I just pictured it being a bit bigger than it is. Looks sharp, and feels solid. Haven’t used it with ice cold or hot drinks yet.