I've read wiki but I'm still not clear about what convection is. I know it is the movement of particles in a fluid but movement caused by what? Diffusion for example is the dispersion of particles caused by random movement of particles due to their inherent energy.

What causes convection though? Is convection just a broad term encompassing all movement of particles within a fluid?

Temperature or gravity.

So it is just movement caused by anything? Thanks.

Does convection by definition imply that these particles in motion are being moved by an external force? For example lets say I swirl a glass of water then drop some red dye into the glass. The red dye will swirl with the water. Would it be correct to say that the red dye is being convected by the water which was already in motion?

Would it be incorrect to say that the water is being convected because although it was me stirring it that caused the water to swirl and although initially the water was being convected by my hand (or the spoon) once it is in motion and I'm no longer stirring then the kinetic energy is contained within the water molecules themselves therefore they are no longer being convected by an external force and are therefore no longer in convection?

Have I got the right idea here?

umm im not a physicist and i may be wrong, but dye doesnt convect into a solution. it diffuses from a high concentration (the point where the dye is added) to a low concentration (everywhere else)

think of this analogy: there were 10 people in a room. One person was given 20 heavy bags to carry. he would give the bags to people around him so each person only carries 2 bags. at this point, no one can give or take anymore bags without getting more than they need.

i have learned convection to be one of the three methods of transfering heat. convection is the movement of heated particles in a fluid medium.

where as conduction involves stationary objects, and the heat in one particle gets transfered to everything around it until everything is the same temperature, convection transports heat by moving heated particles.

i think movement occurs because hot fluids rise and cold fluids sink. in a closed environment, this would cause little loops to occur.

The dye doesn't diffuse instantly though. Takes a few seconds. I've seen it in action. Stir a glass of water and add a drop of two of dye and you will a swirling trail of dye before it dissolves into the water.

Its confusing because wikipedia says one thing, the dictionary says another and tutorials say other things. Wikipedia states that convection actually encompasses diffusion too as well as advection. I would be inclined to think of convection as particles being transported by the fluid medium its contained in but wikipedia states that that is actually advection and convection is a combination of diffusion (browns motion) and advection.

The dictionary seems to give alot of erroneous definitions when it comes to scientific subjects. The dictionary I checked stated that convection was only the transport of heat by a fluid such as a liquid or gas. Thats only one part of heat convection. Theres alot more to convection than that.

Wikipedia: not a very reliable source.
Dictionary: Not concise or indepth
Tutorials: Not indepth, if you are referring to what I think you are.
Solution: Go to your local library (school libraries have a more limited selection) and look at a book on physics. Preferably one on thermodynamics.

Perhaps my understanding of convection is shitty but yall seem to bee awfully far from what I call convection.

To me convection is the movement of gases liquids (and very gooy solids) because of heating. the substance is heated and because it is less dense and lighter it moves up, after reaching "up" is is cooled because it is away from any heat source. because it is cooler it sinks and returns to the heat source. its the idea employed by lava lamps

Ian thats heat convection. Theres alot more to convection than that.

study the ocean and give me a ring