Osmosis vs diffusion

[Exantuate]

I teach junior high. Could someone clarify, would soaking paper towel in food coloring water be diffusion or osmosis or both? Explain which aspect is considered osmosis? Diffusion?

I.e. celery stalk in food coloring water is osmosis, because water particles are travelling through semipermeable membrane. What about the solute (food coloring), travelling upwards along with water particles, area of high to low concentration. Would this be considered diffusion?

How to distinguish the two. 

[Dagl1]

Is there a semipermeable membrane left in the paper towel? 

What is osmosis? What makes the water move, what is it based on?

What is diffusion?

(the rules of this part of the forum are not about straight up answers, and I am not sure if the fact that you are teaching junior high changes that)

[swansont]

The key, I think, is "what is flowing/moving?" in the two cases. Is it the solvent or solute?

[Exantuate]

The basic definitions are of course comprehended here. 

Osmosis, travelling of water particles through selectively permeable membrane. From a place of low solute to high solute.

Diffusion, travelling of solute and or solvent from high to low concentration gradient.

My question is, considering that food coloring is solute. Water as universal solvent. Would it be fair to assume, food coloring travelling up paper towel is considered diffusion, and water travelling to paper towel is osmosis? (Paper towel essentially acts as a semi permeable membrane because of material difference)

There are conflicting answers on the internet. Some clarification here would be wonderful, so I don't need to post at an alternative forum. 

[swansont]

23 minutes ago, Exantuate said:

The basic definitions are of course comprehended here. 

Osmosis, travelling of water particles through selectively permeable membrane. From a place of low solute to high solute.

Diffusion, travelling of solute and or solvent from high to low concentration gradient.

My question is, considering that food coloring is solute. Water as universal solvent. Would it be fair to assume, food coloring travelling up paper towel is considered diffusion, and water travelling to paper towel is osmosis? (Paper towel essentially acts as a semi permeable membrane because of material difference)

There are conflicting answers on the internet. Some clarification here would be wonderful, so I don't need to post at an alternative forum. 

I'm not sure how paper towels would be a good example of either, since the paper towel is not a solvent. Water moves in a paper towel because of capillary action. For either diffusion or osmosis I think you need to have the solvent (or medium) already in place.

 

[Exantuate]

There are other great examples of diffusion and osmosis for sure. The reason I asked in specific reference to the paper towel, because I would like to explain the science behind the paper towel and food colored water - in accordance to the two concepts: osmosis and diffusion. 

Capillary action is indeed part of this explanation (as is the celery example as well), but would osmosis and or diffusion be able to explain this concept? Or are we ruling out that there is osmosis and or diffusion happening altogether here. 

I can go on and talk about various other aspects such as facilitated diffusion, bonding of water molecules to food coloring...etc. But I only want to ask in reference to osmosis and diffusion for this specific example.