Students explore the journey of milk from cow to ice cream, make ice cream in a bag, and discover how food engineers have developed many different processes for making ice cream. Grades K-2

food engineering: a scientific, academic, and professional field that interprets and applies principles of engineering, science, and mathematics to food manufacturing and operations, including the processing, production, handling, storage, conservation, control, packaging, and distribution of food products

homogenization: the process of reducing the size of fat globules in milk to extremely small particles so the cream does not separate from the milk

pasteurization: a process in which milk (or other liquid) is quickly heated to kill any potential disease-causing bacteria

The journey of milk from cows to ice cream begins on a dairy farm. Cows are milked two to three times a day, depnding on the farm management. The milk is pumped into a cooling tank and then into a milk truck to be delivered to the facility where ice cream is made. There, the cream and milk are separated from each other. The basic ingredients—cream, milk, and sugar—are mixed together and then pumped into a pasteurizer, where it is heated. The hot mixture is shot through a homogenizer where pressure breaks down the milkfat into smaller particles. This allows the mixture to stay smooth and creamy. The mixture is sent to a freezer with spinning blades that force air into the mix which prevents the ice cream from freezing solid. The next step is to add flavorings before packaging the ice cream in containers. After mixing in the flavors and other items like chocolate, nuts, and marshmallows, the ice cream is moved to a hardening room where it is frozen. The ice cream is now ready for distribution to stores or restaurants in refrigerated trucks.

Food engineers apply their knowledge of engineering, science, and mathematics to food processing, production, handling, storage, packaging, and distributing food products. They use the engineering design process to solve problems. Augustus Jackson was a former White House chef who engineered a new process for making ice cream using salt in the 1840s in Philadelphia. The salt lowered the temperature of the ice cream allowing it to be kept cold for a longer time. His ice cream was called "Philadelphia Style." This way of making ice cream is still used today. He packaged his ice cream in metal tins and sold the tins to black-owned ice cream parlors in Philadelphia for $1 a quart. Augustus became one of the wealthiest people in the city of Philadelphia. He is also credited with inventing strawberry ice cream and mint ice cream.² 

1. Provide each student with a sticky note and ask them to write their favorite ice cream flavor on it.
2. Collect the sticky notes and create a bar graph to show how many students like each flavor. The students can then determine the most popular ice cream flavor of the class.
3. Ask the students:
   • "What is the main ingredient in ice cream?" (Milk)
   • "Where does milk come from?" (Cows on a dairy farm)
4. Explain to the students that they will be exploring the journey of milk from cow to ice cream.

Activity 1: From Farm to Freezer

1. Organize the class into groups of 4-5 students. Provide each group with a set of From Farm to Freezer Cards.
2. Ask the groups to put the cards in order of how ice cream is made.
3. Read Ice Cream: The Full Scoop by Gail Gibbons to the class. Stop after reading each page that corresponds with the cards. Using the information from the book, have the groups make adjustments to the order of their cards as needed.
4. View the video How is Ice Cream Made?

Activity 2: Making Ice Cream

1. Prior to this activity, set up a table for each team. For the "Salt Team's" table, set the following: 1 gallon-size resealable plastic bag, 1 pint-size resealable plastic bag, kitchen towel, 1/2 cup milk or half & half, 1/4 teaspoon vanilla, 1 tablespoon sugar, ice cubes, and 6 tablespoons rock salt. For the "No Salt Team," set all of the same materials and ingredients except for the rock salt. Teacher note: A 1/2 cup of milk will make about 1 scoop of ice cream. Consider making enough ice cream beforehand for every student to have a taste or allow each student to make their own ice cream after the demonstration.
2. Divide the class into two teams—The "Salt Team" and the "No Salt Team." 
3. Explain to the class that they are going to try two different techniques for making ice cream—with salt and without salt. Ask the students to predict which technique will work best.
4. Invite students from each team to come to the front of the room and complete one of the following tasks at a time:
   1. Fill the large bag half full of ice. Have the "Salt Team" add the rock salt.
   2. Seal the large bag.
   3. Add the milk into the small bag.
   4. Add the vanilla into the small bag.
   5. Add the sugar into the small bag.
   6. Seal the small bag. (You can use two small bags to prevent leaking).
   7. Place the small bag into the large bag, sealing it again.
   8. Place the kitchen towel around the large bag.
   9. Shake for 5 minutes. (Students may take turns shaking the bag.)
5. After 5 minutes, open the small bags. Which team's ice cream turned out better? 
6. Discuss the importance of salt in making ice cream in a bag. Include the following points in the discussion:
   • The ice cubes in the bag with salt melted faster than the ice cubes in the bag without salt.
   • As the ice melts, it absorbs heat and lowers the temperature. The temperature inside the bag with salt become colder than the bag without salt.
   • Because the bag with salt was colder, the ingredients cooled enough to harden into ice cream.
   • The bag without salt was not cold enough to make ice cream.
7. Allow the "No Salt" team to add salt to their large bag of ice and continue shaking to make ice cream.
8. Provide each student with a taste of ice cream.

Activity 3: Ice Cream Engineering

1. Show the students the Engineering Design Process Image. Explain that food engineers apply their knowledge of engineering, science, and mathematics to food processing, production, handling, storage, packaging, and distributing food products. They use the engineering design process to solve problems.
2. Show the Augustus Jackson Photo. Explain that Augustus Jackson was a former White House chef who engineered a new process for making ice cream using salt in the 1840s in Philadelphia. The salt lowered the temperature of the ice cream allowing it to be kept cold for a longer period of time. His ice cream was called "Philadelphia Style." Read the book Ice Cream Man: How Augustus Jackson Made a Sweet Treat Better by Glenda Armand and Kim Freeman.
3. Show minutes 4:48-5:51 of The History of Ice Cream video.
4. Explain to the students that, over the years, many different ways to make ice cream have been engineered. Show the Engineering Everywhere: Ice Cream video.

After conducting these activities, review and summarize the following key concepts:

• Ice cream is made from milk which comes from cows.
• Food engineers apply their knowledge of engineering, science, and mathematics to food processing, production, handling, storage, packaging, and distributing food products.
• Augustus Jackson was a former White House chef who engineered a new process for making ice cream using salt.

1. https://www.mymochi.com/blog/fun-facts-about-ice-cream-that-you-didnt-know/
2. https://www.blackpast.org/childrens-page/augustus-jackson-1808-1852/ 

• Chuck's Ice Cream Wish (Tales of the Dairy Godmother)
• Dairy Tour 360
• Ice Cream Everywhere: Sweet Stories from Around the World
• Ice Cream Man: How Augustus Jackson Made a Sweet Treat Better
• Ice Cream in a Bag
• Ice Cream: The Full Scoop
• Make Mine Ice Cream