The problem tested in the experiment is whether the protein-osmolyte-water solution stabilizes or destabilizes the unfolded state of proteins. This problem was used to test the mechanism by which osmolytes, small organic compounds, interact with the protein to influence its stability. The proposed hypothesis stated that the free energy of transfer of protein structure from water to a water/osmolyte solution, Δgtr, is negatively correlated with the fractional polar surface area of ​​an osmolyte. Δgtr is the unit used to measure the degree to which an osmolyte stabilizes the protein given that if Δgtr>0 (stabilized) and Δgtr<0 (destabilized). The independent variable was the fractional polar surface area (SA) and the dependent variable was the change in energy or stability (Δgtr). The model had two other adjustable parameters or independent variables: the polar and nonpolar SAs and the interaction between solvent and protein structure. The Δgtr was calculated using all adjustable parameters. The first experiment involved the quantitative solvation model in which the interaction energy of the solvent is a function of the polarity of the interactor. The other experiment concerned the number of energetically equivalent ways to achieve a given interaction as a function of the surface area of ​​the interactor. To perform the experiment the researchers used a 1 M osmolyte solution. Calculations were performed using the X-ray structure of eight stabilizing osmolytes. Although comparisons between osmolyte structure and Δgtr values ​​indicate no obvious correlation, there was a clear correlation between Δgtr and fractional surface polar area (R = 0.88). The second experiment used the quantitative model for solvent (water and osmolyte) to test interactions with main chain polar groups. This indicated that the backbone/osmolyte interactions became increasingly favorable as the osmolyte became increasingly polar. The declared result for 1 M osmolyte concentration, calculated and measured Δgtr values ​​are in good agreement. Especially as the polar fractional surface area increases, the interaction of osmolytes with the protein structure becomes increasingly favorable, i.e. their Δgtr values ​​decrease. The free energy change for folding/unfolding will depend linearly on the osmolyte concentration. The statistical mechanics model was used to calculate the average protein structure energy in osmolyte solutions. Approximately 90% of the calculated Δgtr have a correlation greater than 0.80. The success of the second experiment was consistent with their hypothesis. For solvent interactions, the interactions of the single nitrogen amide and two oxygen carbonyls were used. Each of these sites had a positive, neutral, or negative ether charge presented by the solvent (water or osmolyte).