Casein Glue Lab

Purpose and Background 1.Prepare your notebook for recording observations at each step of the procedure. 2.Predict the characteristics of the product that will be formed when the acetic acid is added to the milk. Record your predictions in your notebook

Materials and Equipment 100 mL graduated cylinder100 mL graduated cylinder 250 mL beaker250 mL beaker 250 mL Erlenmeyer flask250 mL Erlenmeyer flask funnelfunnel BalanceBalance GogglesGoggles Glass stirring rodGlass stirring rod  Pipet  Hot plate NaHCO3 (baking soda)NaHCO3 (baking soda) Nonfat milkNonfat milk Paper towelsPaper towels ThermometerThermometer White vinegar (acetic acid)White vinegar (acetic acid) Wood splintsWood splints Sheets of paperSheets of paper

Preparation 1.Prepare your notebook for recording observations at each step of the procedure. 2.Predict the characteristics of the product that will be formed when the acetic acid is added to the milk. Record your predictions in your notebook

Procedure 1.Pour 125 mL of nonfat milk into a 250 mL beaker. Add 20 mL 0f 4% acetic acid (white vinegar). 2.Place the mixture on a hot plate and heat it to 600C. Record your observations in your lab notebook, and compare them with your predictions in Preparation step 2. 3.Filter the mixture through a folded piece of paper towel into an Erlenmeyer flask. 4.Discard the filtrate which contains the whey. Scrape the curds from the filter paper into the 250 mL beaker. 5.Add 1.2 g of NaHCO3 to the beaker and stir. Slowly add drops of water, stirring intermittently, until the consistency of white glue is obtained.

Procedure (cont.) 6.Use your glue to fasten together two pieces of paper. Also fasten together two wooden splints. Allow the splints to dry overnight, and then test for strength. 6.Clean all apparatus and your lab station. Return equipment to its proper place. Dispose of chemicals and solutions in the containers designated by your teacher. Do not pour any chemicals down drain or in the trash unless your teacher directs you to do so. Wash your hand thoroughly before you leave the lab and after all work is finished.

Observations Record your observations while performing your lab.

Conclusion Write a conclusion based on your observations.