Casein Glue LabCasein Glue Lab

Purpose and BackgroundPurpose and Background

1.1. Prepare your notebook for recording Prepare your notebook for recording observations at each step of the observations at each step of the procedure.procedure.

2.2. Predict the characteristics of the Predict the characteristics of the product that will be formed when the product that will be formed when the acetic acid is added to the milk. Record acetic acid is added to the milk. Record your predictions in your notebookyour predictions in your notebook

Materials and EquipmentMaterials and Equipment• 100 mL graduated 100 mL graduated

cylindercylinder• 250 mL beaker250 mL beaker• 250 mL Erlenmeyer 250 mL Erlenmeyer

flaskflask• funnelfunnel• BalanceBalance• GogglesGoggles• Glass stirring rodGlass stirring rod Pipet Pipet Hot plateHot plate

• NaHCO3 (baking NaHCO3 (baking soda)soda)

• Nonfat milkNonfat milk• Paper towelsPaper towels• ThermometerThermometer• White vinegar White vinegar

(acetic acid)(acetic acid)• Wood splintsWood splints• Sheets of paperSheets of paper

PreparationPreparation

1.1. Prepare your notebook for recording Prepare your notebook for recording observations at each step of the observations at each step of the procedure.procedure.

2.2. Predict the characteristics of the Predict the characteristics of the product that will be formed when the product that will be formed when the acetic acid is added to the milk. Record acetic acid is added to the milk. Record your predictions in your notebookyour predictions in your notebook

ProcedureProcedure1.1. Pour 125 mL of nonfat milk into a 250 mL beaker. Pour 125 mL of nonfat milk into a 250 mL beaker.

Add 20 mL 0f 4% acetic acid (white vinegar).Add 20 mL 0f 4% acetic acid (white vinegar).2.2. Place the mixture on a hot plate and heat it to 600C. Place the mixture on a hot plate and heat it to 600C.

Record your observations in your lab notebook, and Record your observations in your lab notebook, and compare them with your predictions in Preparation compare them with your predictions in Preparation step 2. step 2.

3.3. Filter the mixture through a folded piece of paper Filter the mixture through a folded piece of paper towel into an Erlenmeyer flask.towel into an Erlenmeyer flask.

4.4. Discard the filtrate which contains the whey. Scrape Discard the filtrate which contains the whey. Scrape the curds from the filter paper into the 250 mL the curds from the filter paper into the 250 mL beaker.beaker.

5.5. Add 1.2 g of NaHCO3 to the beaker and stir. Slowly Add 1.2 g of NaHCO3 to the beaker and stir. Slowly add drops of water, stirring intermittently, until the add drops of water, stirring intermittently, until the consistency of white glue is obtained.consistency of white glue is obtained.

Procedure (cont.)Procedure (cont.)6.6. Use your glue to fasten together two pieces Use your glue to fasten together two pieces

of paper. Also fasten together two wooden of paper. Also fasten together two wooden splints. Allow the splints to dry overnight, splints. Allow the splints to dry overnight, and then test for strength.and then test for strength.

6.6. Clean all apparatus and your lab station. Clean all apparatus and your lab station. Return equipment to its proper place. Return equipment to its proper place. Dispose of chemicals and solutions in the Dispose of chemicals and solutions in the containers designated by your teacher. Do containers designated by your teacher. Do not pour any chemicals down drain or in the not pour any chemicals down drain or in the trash unless your teacher directs you to do trash unless your teacher directs you to do so. Wash your hand thoroughly before you so. Wash your hand thoroughly before you leave the lab and after all work is finished.leave the lab and after all work is finished.

ObservationsObservations

Record your observations while performing Record your observations while performing your lab.your lab.

ConclusionConclusionWrite a conclusion based on your observations. Write a conclusion based on your observations.