Does the temperture affect the speed that food dye diffuses through water?

Question

Write a procedure to find out.

Answer 1

Hi, Rachelle.

 

The short answer to your question is "yes".  Since you may have recently dyed eggs for Easter, you would have seen food dye diffusing through room temperature water.  Now, think what would happen if the temperature of the water was reduced to 32 degrees F.  The water would be nearly frozen (i.e., solid).  Do you think that the food dye would diffuse through the water?  I think that it probably wouldn't.  Likewise, think about what would happen if the temperature of the water was raised to nearly 212 degrees F.  The water would almost be at a full boil, and the dye would diffuse very quickly because of that agitation.

 

So, for your procedure, I think that you want to take a number (8 to 10) of like-sized samples of water (I would suggest about 500 ml).  Take one of the samples, measure the temperature of the water.  Add a number of drops (you decide how many, but I would suggest about 4 or 5) of food dye to the water and time how long it takes for the dye to completely diffuse in the sample.  Record your results.  

 

Now, take another fresh sample lower the temperature of the sample by 10 to 15 degrees F.  Again, add the same number of drops of food dye to the sample and time how long it takes for the dye diffuse.  Record your results.

 

Repeat the above with additional samples, but lower the temperature of the sample by an additional 10-15 degrees F.  Add the same number of drops of dye and time how long it takes for the dye to completely diffuse.  Record the results.

 

When you have lowered the temperature to near 32 degrees, you have collected enough "cooling" data.

 

Now, collect "heating" data in the same way, take a fresh sample, raise the temperature of the sample by 10-15 degrees F.  Add the same number of drops of dye, and record how long it takes for the dye to diffuse.

 

When you run out of samples of water, and you should have collected enough data to demonstrate the effect of temperature on the diffusion of food dye in water.  Remember to plot your results.

 

For this procedure, you will need a number of beakers, sufficient distilled water for all of the samples, a thermometer, an ice bath (for cooling the sample - DON'T add ice to the sample as that will increase the volume), a hot plate or burner (for heating the sample), and a stop watch (to measure how long it takes for the dye to diffuse).

 

I hope that this helps.