Why might a hiker prefer a plastic bottle to an old-fashioned aluminum canteen for carrying his drinking water?

First, we need to compare the weight of a plastic bottle with an aluminum canteen. In general, plastic bottles tend to be lighter than aluminum canteens. When hiking, carrying less weight is crucial for comfort and energy conservation, so a hiker might prefer a lighter plastic bottle.

Next, compare the thermal properties of both materials. Aluminum is a good conductor of heat, resulting in a faster change of water temperature inside the canteen depending on the outside temperature. On the other hand, a good quality plastic bottle can provide better insulation than an aluminum canteen - it can keep the water cooler for a longer period in hot temperatures and prevent it from freezing in cold environments. This might be another reason why a hiker would prefer a plastic bottle.

Aluminum canteens can sometimes leave a metallic taste in the water, especially if the water has been stored for some time. Meanwhile, good quality plastic bottles are usually made from food-grade materials that don't affect the taste of the water. So a hiker might prefer a plastic bottle to avoid altering the taste of their drinking water.

Although aluminum canteens are typically more durable than plastic bottles, they can be prone to denting when dropped or hit hard, which can lead to leaks. Also, aluminum canteens might crack when exposed to very low temperatures. Plastic bottles, on the other hand, are less likely to crack or dent, offering more flexibility. A hiker might choose a plastic bottle to avoid possible damage caused by accidents or temperature changes.

Lastly, the hiker might take environmental considerations into account when choosing between a plastic bottle and an aluminum canteen. While both materials have associated environmental impacts, choosing a reusable plastic bottle made from recycled materials might be considered a more environmentally friendly option than an aluminum canteen, depending on the manufacturing process and materials used in each. It should be noted that using a reusable bottle, whether plastic or aluminum, is more sustainable than continuously using disposable plastic bottles that contribute to plastic pollution. In conclusion, a hiker might prefer a plastic bottle for carrying their drinking water due to its lighter weight, better thermal insulation, preservation of taste, flexibility, and potential environmental benefits. However, the choice ultimately depends on personal preferences, the specific qualities of each bottle, and environmental factors considered by the hiker.