- active transport
- the process in which a living membrane expends energy to move substances across

- Bernoulli’s equation
- the equation resulting from applying conservation of energy to an incompressible frictionless fluid:
*P*+ 1/2*pv*^{2}+*pgh*= constant , through the fluid

- Bernoulli’s principle
- Bernoulli’s equation applied at constant depth:
*P*_{1}+ 1/2*pv*_{1}^{2}=*P*_{2}+ 1/2*pv*_{2}^{2}

- dialysis
- the transport of any molecule other than water through a semipermeable membrane from a region of high concentration to one of low concentration

- diffusion
- the movement of substances due to random thermal molecular motion

- flow rate
- abbreviated
*Q*, it is the volume*V*that flows past a particular point during a time*t*, or*Q = V/t*

- fluid dynamics
- the physics of fluids in motion

- laminar
- a type of fluid flow in which layers do not mix

- liter
- a unit of volume, equal to 10
^{−3}m^{3}

- osmosis
- the transport of water through a semipermeable membrane from a region of high concentration to one of low concentration

- osmotic pressure
- the back pressure which stops the osmotic process if one solution is pure water

- Poiseuille’s law
- the rate of laminar flow of an incompressible fluid in a tube:
*Q*= (*P*_{2}−*P*_{1})*πr*^{4}/8*ηl*

- Poiseuille’s law for resistance
- the resistance to laminar flow of an incompressible fluid in a tube:
*R*= 8*ηl*/*πr*^{4}

- relative osmotic pressure
- the back pressure which stops the osmotic process if neither solution is pure water

- reverse dialysis
- the process that occurs when back pressure is sufficient to reverse the normal direction of dialysis through membranes

- reverse osmosis
- the process that occurs when back pressure is sufficient to reverse the normal direction of osmosis through membranes

- Reynolds number
- a dimensionless parameter that can reveal whether a particular flow is laminar or turbulent

- semipermeable
- a type of membrane that allows only certain small molecules to pass through

- terminal speed
- the speed at which the viscous drag of an object falling in a viscous fluid is equal to the other forces acting on the object (such as gravity), so that the acceleration of the object is zero

- turbulence
- fluid flow in which layers mix together via eddies and swirls

- viscosity
- the friction in a fluid, defined in terms of the friction between layers

- viscous drag
- a resistance force exerted on a moving object, with a nontrivial dependence on velocity