National Agricultural Literacy Curriculum Matrix
FoodMASTER Middle: Cheese
6 - 8
Two 1-hour activities
Students will learn about the Law of Conservation of Mass by exploring environmental factors that can impact protein coagulation in milk (cheese-making process). By making qualitative and quantitative observations they will test three possible methods of making curds and whey.
- Acid Adventure student handout, 1 per student
- Maintaining Mass lab sheet, 1 per student
Teacher Demonstration (see lesson Procedures step 4)
- Safety goggles
- Apron (optional)
- 1 cup 2% milk
- 2 small clear plastic cups (labeled “curds” and “whey)
- 1 hot plate or double burner
- 1 cup for massing the milk
- 1 small saucepan
- 1 triple beam balance
- 1 whisk or metal spoon
- 1 black permanent marker
- 1 medium bowl
- 1 plastic spoon
- 1 small strainer (very thin mesh)
Student Lab Materials, per group of 4-5 students:
- Safety goggles
- Aprons (optional)
- 3 plastic spoons
- 1 small strainer (very thin mesh)
- 1 triple beam balance
- 4 Styrofoam cups
- 1 medium bowl
- 1 liquid measuring cup
- 1 black permanent marker
- 2% Milk
- 1 small cup containing 1 tbsp. of baking soda
- 1 small cup containing ½ cup of vinegar
Investigating Your Health Activity:
- Charming Cheese student handout, 1 per student
- Cheese Nutrition Fact Labels
- Students may obtain their own labels or use the examples provided.
Essential Files (maps, charts, pictures, or documents)
- Acid Adventure student handout
- Acid Adventure Teacher Key
- Maintaining Mass Teacher Key
- Cheese Nutrition Facts Labels
- Maintaining Mass lab sheet
casein: a protein that makes up about 80% o milk
coagulation: changing a liquid to a soft semi-solid or solid mass
curds: clumps of casein (coagulated protein) that separates from the liquid when milk coagulates
protein: a class of organic compounds containing Nitrogen, Hydrogen, Oxygen, and Carbon that consist of molecules composed of one or more chains of amino acids
tare: an allowance made for the weight of a container when trying to determine the net weight of a substance
whey: a by-product of cheese production; protein found in the liquid that remains after fat and casein are removed from milk. Whey has a watery appearance and is primarily composed of water soluble proteins, lactose, and minerals
Did you know? (Ag Facts)
- The familiar yellow color to cheese such as mild and sharp cheddar is the result of an artificial dye. All cheese is naturally white, just like milk.1
- There is an amino acid in casein milk protein called tyrosine. When tyrosine hits your brain it triggers mood-boosting neurotransmitters that improve attention, focus, and happy feelings.2
- The holes in swiss cheese are a byproduct of the bacteria used to make the cheese.3
Background Agricultural Connections
Interest Approach – Engagement
- Ask students to brainstorm all of the varieties of cheese they are familiar with. Following the brainstorm, ask students what kind of characteristics differentiate these cheeses. Answers may include color, moisture, taste, softness, texture, etc.
- Ask students what they know about the cheese making process. Follow up by watching the video clip, Consider the Source-Cheese.
Lab: Maintaining Mass
- Review information found in the Background Agricultural Connections section of the lesson, lesson Procedures, and the attached Essential Files.
- Prepare materials for each group. Note that baking soda and vinegar should be pre measured in cups.
- In the investigation below, you (the teacher) will be using a hot plate to demonstrate the curdling properties of milk proteins. Students will investigate the curdling properties of milk protein through non-heat methods.
- Timesaver: Review scale “taring” and instruct students to weigh and label empty containers before performing the lab. Practicing measurement is important for students. However, if time is a concern, students may be provided teacher-determined masses of 1 tbsp. of baking soda and 1/2 cup of vinegar, if desired. Additionally, milk may be poured into pitchers for easier access by students. If time is a limitation, use the demonstration video in the student pre-lab materials in place of the in-class teacher-led demonstration. Provide students with the mock data below after your class has viewed the video.
- Distribute lab materials. It is recommended that materials are organized into stations for easier distribution. Students should be arranged in small groups of 4-5. Each group should receive the lab supplies outlined in the Materials section as well as 1 copy of the Maintaining Mass lab sheet and the Acid Adventure handout.
- Ask students to read Acid Adventure.
- Before beginning the lab investigation:
- Require students to wash their hands.
- Emphasize the importance of practicing good food safety behaviors by not consuming substances used as part of the lab investigation.
- For food safety reasons, DO NOT allow students to taste any casein or whey byproducts.
- Launch the lab by providing a demonstration for your students. The demonstration will show students how to find the mass of the coagulated protein, while revealing that milk will curdle after exposure to high heat. View the demonstration video for illustration and follow the steps below:
- Using a triple beam balance, mass 1 cup of 2% milk. Remember to mass the empty cup first. Record the mass in a location visible to the class to help demonstrate conservation of mass. Have students record the mass of the milk only in Table B under “Un-coagulated Milk” for the “Heat” treatment. Hint: This is a good time to review rules for massing liquids and powdered solids on a balance.
- At high heat, quickly heat the milk to a boil in a small saucepan. Use a whisk or metal spoon to stir the milk as it heats to prevent the milk from burning.
- Once the milk has begun boiling, continue to let it boil for 5 minutes. Be careful to continue whisking the milk as it heats. If the milk gets too hot and is not stirred, it will boil over.
- To determine the quantity of coagulated proteins you will strain and determine the masses of both the coagulated proteins and the liquid remaining.
- Place a clean, clear small cup on your scale. A clear cup is preferred so that students can easily see any coagulated proteins. Determine the mass of the cup.
- Next, place a strainer over a medium bowl and pour the heated skim milk into the strainer. If present, the strainer will catch any coagulated proteins. Using a plastic spoon, scrape the coagulated proteins out of the strainer with a plastic spoon and place them in the clean cup measured in STEP 1.
- Place the clear cup containing the milk proteins that you just scraped from the strainer on your balance. You may need to scrape some coagulated protein from your pot too. The coagulated proteins are called curd proteins. Subtract the mass of the cup from the mass of the cup and curds. Have students record the mass of the curd proteins in Table B under the column labeled “Curd Protein.”
- The left over fluid in your bowl is called whey protein. Determine the mass of a second clean, clear cup. Pour the liquid whey protein into a clear cup. Subtract the mass of the cup from the mass of the cup and whey. Have students record the mass of the whey in Table B under the column labeled “Whey Protein.”
- Begin the student portion of the lab investigation by asking students to observe and make a prediction about treatments that may cause milk to curdle (see the bottom of page 1 of their lab sheet). Based on the teacher demonstration completed in the previous step, students should already know that heat would cause milk to curdle. After the lab, students should recognize the following reactions:
- Heat: Students should observe clear curdling. When milk is heated, a precipitate will form. The heat-sensitive coagulated proteins are mostly whey and can generally be observed on the bottom and sides of the cooking pan. Curd proteins will not form as readily when milk is heated. Milk may have to be heated to higher temperatures (212°F, 100°C) for longer time periods to observe curd formation.
- Vinegar: Students should observe clear curdling. When an acid is added to milk it causes the normal pH (6.5 – 6.7) to fall. A lower pH causes the milk proteins to destabilize. Curd proteins will precipitate and be observable. Whey proteins are not as sensitive to acid as curd proteins and will remain in a colloidal suspension (fluid state).
- Baking Soda: No curdling should be observed. The addition of baking soda will result in an increase in pH. Milk proteins will remain stable.
- Use the Maintaining Mass video to demonstrate the steps that students will now complete in their groups.
- Allow students to work in small groups on the Maintaining Mass lab sheet to complete the lab and respond to questions.
- Allow students to share data between groups. Students should seek to complete their data tables with information for the treatment they were not originally assigned.
- Follow-up with a class discussion about the impact of various environments on proteins (e.g. heat, acidic, basic) and the relevance to the cheese-making process.
Investigating Your Health: Charming Cheese:
- Give each student one copy of the Charming Cheese student handout. This assignment can be completed in class or as a homework assignment.
- Using the information found in the Background Agricultural Connections section of the lesson and the Acid Adventure handout, students should examine the food labels of different types of cheese and compare them based on fat and calcium content. Students can find food labels in the grocery store, USDA’s nutrient database, or by using the examples provided.
- Note: If you choose to use the provided cheese food labels, see the attached Teacher Key for answers. Answers to questions based on other food labels will vary.
- To standardize serving size across nutrition labels, students will need to convert each serving size into the same value (cups, tablespoons, etc.). Students will then need to convert all fractions to a decimal. Finding the largest decimal, the students will then divide it by one of the others. Multiply each number in the nutrition facts label using this answer. For example: 3/4 = .75, .75 ÷ .5 = 1.5. Repeat these steps with the other labels. Please see the example below.
- If completed in-class, allow students to work in small groups on the Charming Cheese student handout and respond to questions.
- Conversion Factors:
- 3/4= .75
- 1/3= .33
- 1/2= .5
- 1/3 cup x CF: .33 x 2.27= .75
- Calories: 140kcal x 2.27= 193 mg
- Carbohydrate: 35g x 2.27 = 79g
- Dietary Fiber: 1g x 2.27= 2g
- Sugars: 31g x 2.27= 70g
- Conversion Factors:
Concept Elaboration and Evaluation:
After conducting these activities, review and summarize the following key concepts:
- Milk is the primary ingredient used to make cheese.
- Cheese provides valuable nutrients to a healthy diet and comes in many varieties.
- Cheese is made after the introduction of specific bacteria causing a chemical reaction in milk.
Bring in a variety of cheese for your students to taste test.
Discuss the water activity properties of different cheese types. Which type of cheese will mold the fastest? (See FoodMASTER Middle: Food Safety)
Have students’ research the role of rennet in the making of cheese.
Suggested Companion Resources
- Biotech Cheese Kit (Kit)
- "Cheese Science-As Gouda as TV Gets" Video Series (Multimedia)
- Consider the Source- Cheese (Multimedia)
- Eat Happy Project video series (Multimedia)
- Hilmar Cheese Company Virtual Video Tour (Multimedia)
- Gourmet Lab: The Scientific Principles Behind Your Favorite Foods (Teacher Reference)
Agricultural Literacy Outcomes
Food, Health, and Lifestyle
- Evaluate food labels to determine food sources that meet nutritional needs (T3.6-8.b)
- Explain the benefits and disadvantages of food processing (T3.6-8.e)
- Identify agricultural products (foods) that provide valuable nutrients for a balanced diet (T3.6-8.g)
- Identify sources of agricultural products that provide food, fuel, clothing, shelter, medical, and other non-food products for their community, state, and/or nation (T3.6-8.i)
Education Content Standards
MS-PS1: Matter and Its Interactions
MS-PS1-2Analyze and interpret data on the properties of substances before and after the substances interact to determine if a chemical reaction has occurred.
Common Core Connections
Reading: Anchor Standards
CCSS.ELA-LITERACY.CCRA.R.1Read closely to determine what the text says explicitly and to make logical inferences from it; cite specific textual evidence when writing or speaking to support conclusions drawn from the text.
CCSS.ELA-LITERACY.CCRA.R.10Read and comprehend complex literary and informational texts independently and proficiently.
CCSS.ELA-LITERACY.CCRA.R.3Analyze how and why individuals, events, or ideas develop and interact over the course of a text.
CCSS.ELA-LITERACY.CCRA.R.4Interpret words and phrases as they are used in a text, including determining technical, connotative, and figurative meanings, and analyze how specific word choices shape meaning or tone.
CCSS.ELA-LITERACY.CCRA.R.7Integrate and evaluate content presented in diverse media and formats, including visually and quantitatively, as well as in words.
Speaking and Listening: Anchor Standards
CCSS.ELA-LITERACY.CCRA.SL.1Prepare for and participate effectively in a range of conversations and collaborations with diverse partners, building on others’ ideas and expressing their own clearly and persuasively.
Language: Anchor Standards
CCSS.ELA-LITERACY.CCRA.L.1Demonstrate command of the conventions of standard English grammar and usage when writing or speaking.
Writing: Anchor Standards
CCSS.ELA-LITERACY.CCRA.W.2Write informative/explanatory texts to examine and convey complex ideas and information clearly and accurately through the effective selection, organization, and analysis of content.