Explain why an egg cooks more slowly in boiling water in Denver than in New York City. (Hint: Consider the effect of temperature on reaction rate and the effect of pressure on boiling point.)

Have you ever wondered why a pot of water would boil differently on a mountain compared to sea level? The key factor at play is atmospheric pressure. Imagine the molecules in a pot of water heated on a stove. When the pressure is high, as it is at lower altitudes, these molecules need more energy to escape into the air. This means they have to reach a higher temperature before they can boil.
At higher altitudes, like in Denver, the atmospheric pressure is lower. The surrounding air pushes less on the water surface allowing molecules to escape at lower temperatures. Therefore, water in Denver boils at a lower temperature than it does in New York City. In practical terms, if you're trying to cook pasta or an egg, you may notice it takes longer because the boiling water isn't as hot as it would be at sea level, altering the typical cooking time needed to achieve the same results.

Chemical reactions occur all around us, including in cooking. The rate at which these reactions occur is fascinatingly sensitive to temperature changes. At its core, temperature is a measure of the kinetic energy, or the energy of movement, of molecules. In a dish you’re preparing, higher temperatures mean molecules are moving faster and colliding more often. These collisions increase the chances of the ingredient molecules reacting and transforming into your delicious meal.
Cooking an egg is essentially a series of chemical reactions. Proteins in the egg white and yolk change structure, or denature, when heated. At higher temperatures, this denaturation process happens more rapidly, which is why cooking an egg in boiling water in New York City, at a higher temperature, would be quicker than in Denver, where the lower boiling point means less heat for the reaction and a slower cook time.

It goes without saying that altitude can throw a wrench in your cooking routine. The lower atmospheric pressure at high elevations means lower boiling temperatures for water, and this has a direct effect on cooking time. For every 300 meters (or about 1000 feet) of elevation, the boiling point of water decreases by about 1 degree Celsius. This doesn’t sound like much, but it can significantly affect the cooking process.
For dishes that require boiling or simmering, the adjustment in cooking times can be crucial. Foods need to be cooked longer at high altitudes to achieve the same level of doneness as at sea level. This is particularly noticeable with items that are sensitive to temperature changes, like eggs or certain cuts of meat. Chefs and bakers often have to adjust their recipes to account for the impact of altitude on cooking times – something worth considering next time you find yourself in a high-altitude city like Denver preparing a meal.