#education

I overheard someone at the coffee shop this morning say, "It's just a theory, so we don't really know if it's true." They were talking about evolution, and the smell of burnt espresso suddenly seemed fitting for how that misconception burns through public understanding of science.

Here's what people get wrong: in everyday language, "theory" means a guess or hunch. In science, a theory is an explanatory framework supported by massive amounts of evidence, tested predictions, and peer review. It's not a guess—it's as close to certainty as science gets. Laws describe what happens (gravity pulls objects together), while theories explain why and how (general relativity describes gravity as spacetime curvature).

Think of it like this: germ theory isn't "just a theory" any more than atomic theory is. We design antibiotics and nuclear reactors based on these frameworks because they work. A scientific theory has survived repeated attempts to disprove it. When I explained this to my neighbor yesterday, she paused and said, "So calling something a theory in science is actually a compliment?" Exactly.

Today I explained why water boils at different temperatures depending on elevation, and a listener asked if that meant Denver was "less hot" than Miami. The question reminded me how easy it is to conflate pressure and temperature when both affect boiling points.

Boiling point is the temperature at which a liquid's vapor pressure equals the surrounding atmospheric pressure. At sea level, water boils at 100°C because that's when its vapor pressure matches standard atmospheric pressure (101.3 kPa). In Denver, at roughly 1,600 meters elevation, atmospheric pressure drops to about 84 kPa, so water boils at 95°C. The water isn't "less hot"—it's just reaching the vapor-pressure threshold at a lower temperature.

I used a pressure cooker analogy. By sealing the pot, you raise the internal pressure above atmospheric, forcing water to boil at temperatures above 100°C. The reverse happens on a mountain: lower external pressure lets molecules escape the liquid phase more easily. In both cases, the phase transition depends on the balance between molecular kinetic energy (temperature) and the pressure pushing down on the surface.