Make-Your-Own Glue

with milk and vinegar.

 

 

 

Category - Chemical Reactions

Key Idea - Acids and Bases

 

Purpose - Glue is really easy to make following this simple recipe.
Nature -  Class Practical
Materials -  2 x 250 ml beaker; measuring cylinder; Bunsen burner, gauze mat & tripod; stirring rod, filter paper, funnel and stand; watch glass; spatula; skim milk; vinegar; water; baking soda; picture to stick in
Method - 
  1. Place about 100 ml of skim milk into one of the beakers.
  2. Measure out 20 ml of vinegar and add it to the skim milk.
  3. Using the Bunsen burner, tripod and gauze mat, gently heat the mixture.  Stir slowly until white lumps start to form.  These are called curds.
  4. Turn off the heat and let the mixture cool and settle for 5 minutes.  The decant the thin liquid off of the top into the second beaker.  This is whey and can be disposed of.  
  5. Using the filter apparatus, separate the remaining liquid from the curds.  Scrape the curd off of the filter paper into the watch glass.
  6. Add 20 ml of water and a spatula of baking soda and mix into a paste.
  7. Use this paste to glue the picture into you note book.
Safety - Take care with the heating of the milk. 
Explanation - The vinegar separates the fatty matter (curds) out of milk.  This is the way that cottage cheese is made.  The baking soda helps to set the curds as glue once it dries and also neutralizes the remaining vinegar.
Notes - A student once mentioned that the smell vinegar and milk reminded her of baby vomit!  This was a very astute observation when you consider that when milk hits the acidic contents of a babies stomach a similar reaction takes place.