text: science stuff!!? if you add 1/2 teaspoon of vinegar or lemon juice to about 1/2 teaspoon of milk, what does it look like before and after? is it a chemical change? note: wait 24 hours 2 see if it changes did you know you can actually make glue from milk? the first step of the process is adding the vinegar to the milk, which will cause the milk to seaprate into solid curds and watery whey.  what's happening here? well, the vinegar is causing the proteins within the milk to bind together, forming the curds. the substance left over is that watery whey protein.  this of course is a chemical reaction because the substance (milk) is converted into a substance with different composition and properties (curds and whey).  for further reference, contact little miss muffet.  hope that helps!!