Turning Milk into Plastic

Turning Milk into Plastic

Abstract

This eighth grade Science Quest experiment explains how plastic can be made from a common household item such as milk. During the experiment each cup holds different amounts of vinegar: cup #1 contains 1 teaspoon of vinegar, cup #2 contains 2 teaspoons of vinegar, cup #4 hold 4 teaspoons, and cup #8 holds 8 teaspoons. By adding 1 cup of heated milk (49-50 degrees) to each cup a chemical reaction occurs, the milk curds form casein plastic. Casein plastic is a type of plastic that is used to make small things such as trinkets and Christmas ornaments. I noticed that the more amount of vinegar in the cup the more curds would form. My hypothesis stated that I will be able to turn the milk into curds, and then to plastic, I was correct in thinking this. My experiment showed how milk contains numerous amounts of casein, a protein, when the milk is heated and added to the acid, vinegar, the casein molecules unfold and reorganize into a long chain, called a polymer, made from monomers, creating curds when molded, later dried and hardened into plastic.

Purpose

The purpose of my experiment is to determine if milk, a common household item, can be transformed or changed into a type of plastic.

Hypothesis

Will I be able to turn milk into plastic using vinegar?

Yes I believe with the right materials and procedure I will be able to make plastic out of milk by pouring heated milk into different amounts of vinegar.

Introduction

Materials

This Science Quest experiment geared toward eighth grade students teaches about a chemical reaction that demonstrates the separation of casein, a type of protein, from milk to form a different form of plastic. Numerous things can be made out of milk such as cheese, ice cream and even plastic. In the early 1900s’ making plastic out of milk was very popular and common in belt buckles and children’s jewelry, but today not so much. Sturdier and more long lasting products are used for those purposes; however making plastic for fun is definitely widespread. A chemical reaction that occurs in this experiment is when a change in which one or more substances are converted into new substances. For example, in the experiment, milk is heated and combined with an acid, like vinegar, the casein molecules unfold and reorganize into a long chain. Each casein molecule is a monomer and the chain of casein monomers is a polymer. The polymer can be picked up and molded, which is why plastic made from milk is called casein plastic. This lab experiment helped me understand the uses and importance of the substance we call plastic.

• 4 Identical Heat-Resistant Cups or Mugs (should hold more than a cup of liquid)

• Masking Tape

• Permanent Marker

• Teaspoon

• White Vinegar (at least 8 cups)

• Milk (at least a gallon) : Skim, 1%, 2%, and whole milk will all work

• Microwavable liquid measuring cup (should be large enough to hold 4 cups)

• Microwave

• Candy Thermometer

• Spoons

• Cheese Cloth

• Rubber Bands

• 4 Clear Drinking Cups

• Kitchen Scale (accurate to 1 gram)

• Paper Towels (for spills)

• Wax Paper to cover Kitchen Scale

• Lab Notebook to Record Data

• Molds, Cookie Cutters, Food Coloring, Paint, Glitter or and Permanent Markers (optional)

Conclusion

In conclusion, this eighth grade Science Quest experiment taught me that it’s not so easy making your own plastic and the science behind it all. It helped me understand and finish the project on my own with no distractions and complete it well rather than just imagining the experiment while reading its procedure. Generally I learned and now understand why casein plastic isn’t used as much in household items but in kid’s activities and crafts, I can apply this lab to things in my daily life and at school.

Procedure

• Using a pen and masking tape, label the four mugs you have set aside as: 1, 2, 4 and 8.

• Take the measuring spoon and add 1 tsp. of white vinegar to the mug labeled “1”, 2 tsp. to the mug labeled “2”, 4 tsp. to the one labeled “4” and 8 tsp. to the one labeled “8”.

• Heat up the 4 cups of milk in a measuring cup in the microwave:

a. The time needed to heat up the milk depends on your microwave. Start by heating up the milk at 50% power for 5 minutes to keep the milk from burning.

b. The milk should be at least 49 degrees.

c. Make sure to right down data about heating up the milk.

• Pour 1 cup of the heated milk into each of the four mugs. Make sure that you pay attention because one of the mugs contents should be separated into white clumps called curds.

• Mix each mug with a spoon for a few seconds to make sure the vinegar reacts with the milk as much as possible.

• Take one cotton cloth square and tie it around the top of one of the clear cups with a rubber band so it completely covers the top of the cup. Repeat with the other cups.

• Once the vinegar mixture has cooled carefully pour it into the clear cup separating the curds from the juice.

• Over a sink remove the cloth from the top of the cup and squeeze all of the liquid out of the rest of the curds. Scrape the curds of the cloth and knead them together. This is casein plastic.

• Weigh each ball of casein plastic (set for grams) and record the data.

• Now you can mold your casein plastic into anything normally make from plastic like, Christmas ornaments and little knickknacks, you can even color it with food coloring. Then leave it on a towel to dry for 48 hours and enjoy your trinket made from milk!