Stress–energy–momentum pseudotensor

Imagine you are playing with your toy car, and you push it forward. You feel the push you gave it, right? That's because you put some force or energy into it. When scientists talk about force, they use a fancy word: "momentum."

Now, imagine you put your toy car on a big trampoline or springboard, and you jump on it. The trampoline or springboard stretches and bends, but then it also springs back, which makes you bounce. That's because the trampoline or springboard can "store" your energy, kind of like how a rubber band stretches then snaps back when you let go. Scientists talk about how much energy something can store or how much it stretches or bends. They call it "stress."

When you put your toy car on the trampoline or springboard, it doesn't stay still, right? It moves a little because the surface is bending and stretching. Scientists talk about how things move, too. But when they talk about how things move because of stress and energy, they use a really fancy word that sounds almost like "pseudotensor."

So, when scientists talk about stress-energy-momentum pseudotensor, they mean a way of describing how much force or energy something has, how much it can bend or stretch, and how it moves because of that. It's like a really fancy way of explaining things that move, stretch, and store energy, like a trampoline or springboard. But it's just a fancy word and concept for something you already know and play with!