Key idea
Flow and continuity
Fluide incompressible : A₁v₁ = A₂v₂
Start with the central idea, then test it against a concrete element or example. A scientific model is useful when we know what it explains — and where its limits are.
Flow and continuity
The key idea
For steady flow, conservation of mass constrains how density, cross-sectional area and flow speed vary along a stream tube.
Why it matters
For an incompressible fluid, narrowing the available area increases the mean flow speed.
A picture to remember
Key idea
Flow and continuity
Guided example
Flow and continuity
Start with the central idea, then test it against a concrete element or example. A scientific model is useful when we know what it explains — and where its limits are.
Put it into practice
Flow and continuity
Choose a concrete case linked to Flow and continuity. Write down the known information, what you are trying to find, and the units. Then state the rule, model or trend you will use. If a calculation is involved, keep the units visible at every line; if it is conceptual, state what changes and what remains fixed.
Check your answer
A strong answer contains four things: the starting situation, the variable that changes, the direction or numerical result, and one check. The check can be a unit, an order of magnitude, a limiting case or a comparison with a familiar example.