The four pillars of the universe — mechanics, electromagnetism, thermodynamics, and the quantum — with labs you can touch.
Everything that moves obeys three laws. Force changes momentum. Energy is never created or destroyed — only moved around. Master F = ma and you can predict cannonballs, planets, and roller coasters.
Push something and it accelerates in proportion to the push, in inverse proportion to its mass. This one equation runs all of engineering.
A falling object trades height for speed. The books always balance — energy is the universe's one unforgeable currency.
The same inverse-square law that drops your coffee keeps the Moon in orbit. Falling is just orbiting interrupted by the ground.
Galileo's insight: horizontal and vertical motion are independent. Set an angle and speed, fire, and watch gravity do the only thing it knows.
Four equations unified electricity, magnetism, and light itself. Charges make fields, changing fields make each other, and the resulting wave travels at exactly c — which is how we discovered light is electromagnetism.
Same shape as gravity, but 10³⁶ times stronger. The reason you don't fall through your chair is electrostatic repulsion between electrons.
Voltage pushes, resistance pushes back, current is what gets through. Every circuit you've ever used is this sentence.
Two numbers measured in a lab with charges and magnets predicted the speed of light before anyone connected them. Possibly the greatest "oh." in science history.
Two waves overlap and simply add. Where crest meets crest: constructive interference. Where crest meets trough: cancellation. Slide the wavelength and source separation.
Heat is motion. Temperature is the average jiggle of atoms. And entropy — the universe's tendency to spread out — is why time has a direction and why you can't unscramble an egg.
Conservation of energy, restated for engines. You can't win — the house always balances the books.
You can't even break even. Disorder grows; that's the arrow of time. Every refrigerator, star, and thought you have pays this tax.
Carved on Boltzmann's tombstone. Entropy is counting: there are vastly more disordered arrangements than ordered ones, so disorder wins by sheer numbers.
At small scales nature stops being definite. Particles are waves of probability until measured, energy comes in packets, and knowing position exactly means knowing nothing about momentum.
Light isn't a smooth stream — it arrives in grains called photons. h is tiny (6.6×10⁻³⁴), which is why the world looks smooth to us.
Not a measurement flaw — a property of reality. A particle doesn't have a perfectly defined position and momentum at once.
Electrons diffract like waves. You have a wavelength too — about 10⁻³⁵ m. Unmeasurably small, so you get to stay solid.
A qubit can be in superposition: heads and tails at once until observed. Set the probability, flip, and watch the Born rule — |amplitude|² gives the odds.
The speed of light is the same for everyone — so time and space must flex to compensate. Moving clocks run slow. Gravity is not a force but the curvature of spacetime itself.
GPS satellites gain 38 microseconds a day from this (plus gravity). Without the correction, your maps would drift 10 km daily.
c² is enormous: one gram of mass holds the energy of a small nuclear weapon. The Sun burns 4 million tonnes of itself per second.
Gravity isn't a pull — you're following the straightest possible path through bent spacetime. Black holes are where the bending wins.