Adult Ed

Summer Science Recipes: Experiments on the Grill and in the Kitchen

Overview | Activities

Introductory Activities | Learning Activities | Culminating Activity
Cross-curricular Extensions | Community Connections

Introductory Activities - Power of Lemon

  1. Lemonade-solutions and mixtures
    Make a few glasses of lemonade in a few different ways; record your observations on the "Lemonade Recipes" sheet

    • First recipe-use reconstituted lemon juice, water and sugar
    • Second recipe-use freshly squeezed lemon juice, water and sugar
    • Third recipe-use lemonade-flavored mix (pre-sweetened) and water
    • Fourth recipe-use hot water instead of cold water to dilute the lemon juice and sugar mixture

  2. As you record your observations try to answer the following questions after each step on the handout:

    • Mix all ingredients in a transparent container (a glass works well) until all of the sugar is dissolved. Taste a small amount. Save at least 1/2 of the drink for experimentation. What (if anything) is different about the taste? What other differences do you notice?

    • Use a coffee filter and a funnel to filter 1/4 of each sample (about 2-ounces). What do you notice now?

    • Place the remaining sample (about 2-ounces) in a small saucepan and allow it to boil gently over a medium heat. What do you notice?

    • For example observations review the Lemonade Recipe Observation Example document.

  3. Lemon wash-preventing oxidation
    Peel fruit (apples, pears, peaches, plums, bananas, and kiwi) and slice them to a medium thickness (about 1/4" slices). Divide fruit into three samples. Put 1/3 of the fruit on a paper plate and allow it to sit on a counter. Onto a second plate, place another 1/3 of the fruit but coat it with a small amount of lemon juice before allowing it to also sit on a counter space. Place the last 1/3 of the fruit in a bowl of ice-cold water and allow it to sit on the counter as well. Observe what happens after 5-minutes, 15-minutes, 30-minutes, 1-hour, and 2-hours. Record your observations. Which fruit would you still be willing to eat? Why?

    NOTE: Presentation and the way food looks is almost as important as the way food tastes. Most people are willing to eat those fruit and vegetables that maintain their bright colors and have not been obviously oxidized to appear dark brown. "Quenching" vegetables in ice-cold water also helps to keep them vibrant and crisp, thanks to a biochemical process called osmosis. For an alternative experiment visit Penn State University's Oxygen Experiments Web page

  4. Lemon Marinade-denaturing proteins
    Complete the denaturing (Introductory Activity Step 3) exercise from the NTTI SAY CHEESE lesson. What happens to the egg white? Why is this observation relevant to cooking during the summer?

    NOTE: The egg white appears to be "cooked" after sitting in the concentrated lemon juice. The albumen (or albumin) becomes opaque and firm as a result of the acid in the juice. This same process is used in the preparation of mayonnaise and salad dressings that use raw eggs. It should be noted that consumption of raw eggs can be dangerous because small microorganisms called bacteria can cause serious sickness and/or disease; these bacteria are responsible for food poisoning. Care must be taken when serving dishes prepared with raw eggs. One of the learning activities in this lesson will allow you to cultivate different microorganisms safely.

Learning Activities - Discovery Across Science Disciplines

  1. General science-Types of Mixtures
    Read the essay "HOW CHEMICALS BEHAVE" in the "GED Connection Social Studies and Science Workbook," p. 214. On index cards, write down the descriptions of at least two examples of each type of mixture: solution, colloid and suspension. Complete the "Skill Practice" at the bottom of the page.

    NOTE: A solution is a mixture made of two components that become indistinguishable from each other upon mixing. It is a type of physical mixture because with some work, the two parts can be separated. The two parts, the solute and the solvent, of a solution can be separated by processes like evaporation and distillation. A colloid and a suspension also contain multiple components which can be physically separated, however, it is much easier to separate the parts because the particles are "larger" than those commonly found in a solution. Examples of a solution are: table salt dissolved in water, carbon dioxide dissolved in water (carbonated water) and water vapor dissolved in air (humidity). Colloid examples include: butter, milk, cream, glues, inks, and paints. Some examples of suspensions are: mayonnaise, mud and gelatin.

    When the substances that make up a mixture combine to form a completely new substance by forming new chemical bonds, it is not a mixture at all! These substances are called compounds because they are chemically different from the original substances used to make them.

  2. Chemistry-Redox reactions
    Read the "GED Connection Social Studies and Science Workbook" essay "ACIDS AND BASES," p215. The authors explain the major ideas behind acid-base chemistry. In your reading, make sure to identify at least three properties of acids and three properties of bases. Use the Acid-Base Information checklist as a guide when reading the essay.

  3. Use the GED Connection Handout and follow the directions for accessing GED Connection activities online. These Web pages will help you see how each component of this lesson builds to form a unique opportunity to convert your kitchen into a laboratory.

    NOTE: Most of us have seen brown fruit or black asparagus, but have you ever seen gray soup? These observations are the result of the same kind of process you observed during the introductory activity, "Lemon wash." When organic matter is exposed to air, a chemical process called oxidation occurs. Many fruits and vegetables that have been left out too long change colors as a result of oxidation. The Food Science Web page reviews key concepts discussed in this lesson, including acid-base chemistry concepts, microorganisms in the kitchen, complex carbohydrates and cellular processes like osmosis.

  4. Read the America's Test Kitchen Web site Blue Onion Soup explanation and discover another reason why acid-base chemistry is so important to the chef.

  5. Life Science-Biological Molecules
    You were first introduced to a type of organic compound called proteins in the introductory activity "Lemon Marinade." In this portion of the lesson, you will study microorganism growth on a piece of bread! Microorganisms are a different type of organic "compound" -- they are considered animals and are classified in their own kingdom. Log onto the Bread Bag Nightmare Web site and complete the assigned procedures (data should be collected for a minimum of 10 days).

  6. After you have conducted the Bread Bag Nightmare experiment, try to answer the following:

    • What conditions in the summer kitchen make this experiment particularly easy to conduct at home?

      Answer: See step 4 of the experiment. There are several factors that influence the growth of mold: high levels of moisture, sugar, darkness, and warm temperatures are all positive growth factors for many microorganisms. In the summer, especially in the Northeastern U.S., the region tends to be humid and hot, which are ideal conditions for microorganism growth, including that of bacteria.

    • How will you know the difference between bacteria and mold?

      Answer: See the answer to question #3 on the Bread Bag Nightmare site. Bacteria are microorganisms that are commonly associated with food spoilage in much the same way that mold is. Generally there are two major differences between bacteria and mold: 1) bacterial food spoilage is usually accompanied by a foul odor whereas the presence of mold is not usually accompanied by any smells; 2) bacterial colonies are usually smooth whereas mold colonies are fuzzy, due to the spores growing on the surface of the food.

    • Think about other types of "healthy" microorganisms found in food or drugs and brainstorm a list and identify the kinds of science associated with those items.

      Answer: Common microbial foods or drugs include blue cheese, yogurt, penicillins, yeast, pickles, sauerkraut, beer, and coffee. Log onto to learn more about the microorganisms humans use to help them digest many of the foods we enjoy.

Culminating Activity - All Hands In

  1. Marinade recipes
    Visit the Marinades Web site to get a few good recipes for marinades. After finding a marinade recipe to suit your needs, identify the three major ingredients in the recipe and the role each serves in preparing the food.

    NOTE: The three major ingredients in a meat marinade are acid (denatures and softens the protein); oil (adds flavor and moisture to the meat); spices/aromatics (gives the meat extra flavor).

  2. Salad Express
    Using what we have learned about acidity and osmosis make a fabulous tossed salad. Keep lettuces and vegetables crisp by rinsing them in water and shaking the water off before using. IF you prefer to make a fruit salad spritz it with a little lemon juice before serving to prevent browning.

Cross-curricular Extensions
  • English/Biography: PBS American Masters-Julia Child
    The American Masters series showcases the life and work of some of the most brilliant personalities in U.S. history and public opinion. No one has made as great an impact on television cooking than Julia Child. Watch the program and visit the companion American Masters Web site to learn more about this iconic individual.

  • Biology: Ever wondered?
    Since we are talking about food, this might be a good time to review the digestion process! Visit this BBC companion Web site (Flash plug-in required) to see what happens when we ingest food and answer the quiz questions for fun.

  • Print out the Beef Map from the Good Eats Web site, and "poke around" at a local grocery store's meat section to try to determine why certain cuts of meat have the characteristics they exhibit. Then, develop your own theory about the toughness or the tenderness of these cuts by using your knowledge about the physiological and cellular properties of different types of muscle. Test your "theory of toughness" by trying different recipes and techniques for infusing flavor and tenderness into your meat samples.

  • Math: Recipe Factoring Doubling-Halving
    Take your favorite recipe and identify what proportions of ingredients would be required to double, triple or halve the recipe. For example, a simple recipe for cereal bars calls for only three ingredients in order to make 36 bars-1/4 cup butter, 10 ounces of marshmallows and 6 cups of cereal. Ask yourself how many bars can you make if you have 1 cup of butter, 40 ounces of marshmallows and 24 cups of cereal? Or what is the greatest amount of bars you could make with 2/3 cups of butter, 25 ounces of marshmallows and 8 cups of cereal? When carrying out quantitative chemistry experiments, this skill is critical for calculating amounts of reactants and products necessary for the specific reaction to occur. Another term for this branch of chemistry is "stoichiometry." Once you have mastered this skill, you are ready to start planning actual chemical reactions in a lab, not just in a kitchen!

Community Connections

  • Interview a chef to determine some recipes for making various types of marinades, gravies or baked goods. As you record the recipes, identify the ones that will require some understanding of food science (pH, solution analysis or microbiology) in order to make them work. Ask the chef how he or she comes up with new recipes and how much science was required in their own culinary studies?

  • Preserve meat for the winter: In the Bread Bag Nightmare experiment, you used lemon juice as a kind of preservative for the bread. Throughout history, salt has been another very important preservative for food. Obtain a small piece of meat (about 4 ounces) and enough salt to cover the meat completely. Place the salted meat in a container of salt and allow it to sit undisturbed. After a few hours, you may notice water in the bowl, don't be alarmed because that's the reaction you want! Remove the salted meat after a day or two and put it in a fresh bowl of salt and repeat the process until the meat is completely dry and "cured." The meat will be considerably smaller in size than it was originally and you will notice that it feels a lot tougher than it felt when it was fresh (Note: this process may take a week or longer depending on your kitchen conditions). When you are sure that the meat is completely dry, put the salted meat in a tightly sealed storage container or freezer. Use the preserved meat to season a pot of soup or vegetables in the winter. Visit the America's Test Kitchen Web site to discover additional ways of "infusing meat with moisture and flavor" or find out more about the "ancient art of salting meat."

  • Research science careers online at the Vocational Information Center or Careerzone. Find out what knowledge and skills are required to pursue these careers and create a profile sheet that compares a baker to a butcher, a food science researcher or a cheese maker, or any combination that interests you.