Which Cup Will Sugar Dissolve Faster In? Why?

  • Context: High School 
  • Thread starter Thread starter BakyX
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Discussion Overview

The discussion revolves around the question of which cup will allow a sugar cube to dissolve faster when one cube is fixed above the bottom of the glass while the other rests on the bottom. Participants explore the reasons behind their observations and propose various factors that may influence the rate of dissolution.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested, Experimental/applied

Main Points Raised

  • One participant notes that the sugar cube in the first cup, resting on the bottom, has only five sides exposed to water, while the cube in the second cup has all six sides exposed, potentially leading to a faster dissolution.
  • Another participant suggests that the motion of the sugar cube falling to the bottom may contribute to a quicker dissolve, and raises the possibility that variations in water volume and glass shape could affect results.
  • Concerns are raised about the influence of environmental factors, such as humidity, on the dissolution rate of sugar cubes, with a suggestion that a sugar cube exposed to moist air might dissolve more quickly than a dry one.
  • One participant speculates that sugar molecules, being heavier than water, may sink and create a higher concentration of sugar around the cube resting on the bottom, potentially slowing its dissolution rate.
  • A suggestion is made to conduct further experiments by suspending sugar cubes at different heights within the glass to test the effects on dissolution rates.

Areas of Agreement / Disagreement

Participants express differing views on the factors influencing the dissolution rate of sugar cubes, with no consensus reached on which cup will definitively allow for faster dissolution or the reasons behind their observations.

Contextual Notes

Participants acknowledge various assumptions, such as the uniformity of water temperature and volume, and the potential impact of different environmental conditions on the dissolution process. The discussion remains open-ended regarding the specific effects of these factors.

Who May Find This Useful

This discussion may be of interest to individuals exploring the principles of solubility, experimental design in chemistry, or those curious about the effects of physical conditions on dissolution rates.

BakyX
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I have two same glasses. In both glasses I have water with the same temperature. I put sugar cube to the first cup and in the second cup I fix sugar cube so that the cube doesn’t touch bottom of glass. In which cup will sugar dissolve before ? Why ?

Hello..Next problelm..At first, sorry for bad english. At second..I try it and sugar dissolve before in the second cup..But there is still question WHY

Thanks everyone for help
 
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i assume the sugar cube in first cup fell to the bottom and came to rest with bottom surface flush with bottom of the glass..correct
the cube wit hall 6 sides exposed to the water will dissolve simply because more area is exposed ..the sugar cube resting on the bottom has only five sides exposed to the water
 
Last edited:
No SURE way to tell...maybe the motion abrasion of falling all the way to the bottom of the glass results is a quicker dissolve...if the volumes of water are different and the shapes [depths] of the glasses that could also affect the results...

but keeping things simple I agree with the logic above...

How much of a difference did you observe?? How often did you repeat the measurements??

One sugar cube exposed to humid moist air before immersion might dissolve more quickly than a dry one in an air tight container...I would guess...

Different brands may differ in dissolution characteristics...how artificial creamer particles dissolve was apparently a big issue with those products...and reportedly took lots of experimentation...
 
Besides the more surface area in the second case, I wonder if, as sugar molecules are heavier than water, they will tend to sink to the bottom of the glass. This would mean the sugar cube on the bottom of the glass will be surrounded by a solution with a higher sugar concentration as it dissolves, perhaps near saturation. So the rate of dissolving (per surface area) would be lower for the sugar cube at the bottom of the glass.

But I could be wrong, and the dissolved sugar might distribute pretty uniformly thoughout the glass.

To test this, you could do the experiment with both sugar cubes suspended; one near the bottom of the glass and one near the middle or top.
 

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