There are so many little things I didn't think of before the first time I went to Antarctica that make a difference. I like having clean teeth, so brushing twice a day is very important to me, even in the field. I can handle dirty hair, but not dirty teeth. It's hard to brush your teeth when your toothpaste is frozen into its tube. That small hole at the top requires the toothpaste to deform to get out. And that part gets cold the fastest, often getting clogged with a plug of toothpaste ice. This isn't so much a problem in December in the Dry Valleys, nor was it a problem at Lake Untersee, because although the temperatures are often below freezing, sunlight heated my tent sufficiently during the day that the temperatures inside could be up to 20°C (70°F!). However, in October at Lake Joyce, I couldn't get any toothpaste out of a big tube without warming the top of the tube against my stomach. There is a little secret, though: small tubes warm up faster. Wit
