Science & Math Terms, Explained
Textbook definitions manage to be accurate and useless at the same time. These pages take the concepts that come up in chemistry, physics and calculus and explain what they actually mean, why they behave the way they do, and where they show up outside an exam hall. Written for anyone who wants the idea, not just the definition.
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What is a Derivative?
The rate of change at one exact instant — the speedometer to the odometer's total.
What is Entropy?
Why heat spreads, ice melts, and rooms never tidy themselves — counting arrangements, not forces.
What is pH?
The 0–14 acidity scale where every step is ten times — and why blood guards its number.
All 13 terms
What is Activation Energy?
The energy hill every reaction climbs before it starts — and how catalysts shorten it.
What is Continuity?
No jumps, no holes: why some graphs can be drawn without lifting the pen, and what breaks it.
What is a Derivative?
The rate of change at one exact instant — the speedometer to the odometer's total.
What is Electronegativity?
How hard an atom pulls shared electrons — the tug-of-war behind polar bonds and water's powers.
What is Entropy?
Why heat spreads, ice melts, and rooms never tidy themselves — counting arrangements, not forces.
What is an Integral?
Adding up endless tiny slices to get a total — distance from speed, area from a curve.
What is Le Chatelier's Principle?
Disturb a balanced reaction and it shifts — settling at a new balance, not the old one.
What is a Limit?
Where a function is heading as it closes in on a point — even when it never arrives.
What is Momentum?
Mass times velocity — the motion an object carries, and why crumple zones save lives.
What is Newton's Third Law?
Every push comes with an equal push back — on a different object, which is why things move.
What is pH?
The 0–14 acidity scale where every step is ten times — and why blood guards its number.
SN1 vs SN2 Reactions: What's the Difference?
One-step shove or leave-then-fill: how crowding on a carbon picks the substitution route.
What is Torque?
Force times distance from the pivot — why long handles beat strong arms.