Physics of Energy

Physics of energy explores how energy moves, changes, and powers everything—from atoms to engines to the entire universe. ⚡🌍🔬

What is energy? The most important thing in physics that nobody can point to

Illustrated featured image about energy showing a scientist examining the Sun, a battery, a kettle, a moving object, and an atom as different expressions of energy.

Energy powers stars, batteries, bodies, power grids, and basically everything that changes. But ask physics what energy actually is, and the answer gets strange fast. Energy is not a substance, not a force, and not simply “the ability to do work.” It is something deeper: a measurable property of physical systems, a conserved quantity tied to the structure of time itself—and, at the frontiers of physics, a concept whose full meaning is still surprisingly unsettled.

What is a heat pump? The heater that refuses to make heat

Illustrated winter scene showing a heat pump outside in the snow sending warm glowing heat into a cozy home where a family sits indoors.

A heat pump can deliver three or four units of heat while using roughly one unit of electricity. No, it is not breaking physics. The trick is that it does not create most of the heat—it moves heat that was already there. Here is why your refrigerator, air conditioner, and one of the biggest technologies in building decarbonization are basically members of the same family.

What is heat? The energy that refuses to sit still

Digital heat illustration showing a steaming mug transferring heat toward a cold ice cube, demonstrating heat flow from hot to cold.

Heat is everywhere—from your morning coffee and electric kettle to power plants, weather systems, factories, and the warming planet. But here’s the twist: heat isn’t actually something an object “contains.” It’s energy on the move. Let’s unpack what heat really is, how it travels, why temperature isn’t the same thing, and why this invisible energy transfer sits at the center of the modern energy system.

What is nuclear fission? The weird atomic trick that boils water and powers cities

Featured illustration of nuclear fision showing an atom splitting and releasing energy next to a boiler, steam system, and turbine generator producing electricity.

Nuclear fission sounds like the kind of thing you should only discuss in a bunker with three physicists and a lockbox. It is actually much simpler than that. Split a heavy atom, collect the heat, boil water, spin a turbine, make electricity. Here’s what nuclear fission is, why it exists, how it works, where it shows up in real life, and why it matters more right now than a lot of people realize.