The delicious science of lollipops - teaching science

Making candy shows kids how temperature affects matter.

Some of the most successful science explorations arise out of children's frank questions. This lollipop lesson came from my seven-year-old son, Ty. One afternoon last February my husband and I and our three children set out for a drive through the winter countryside. After passing huge sugar maples linked to barrels with a bright blue hose, we had a lively discussion about how maple syrup is made. A few miles down the road, Ty asked, "Where do they come from?" My husband gave me a sidelong glance. I turned around and smiled at Ty's baby sister. I was pretty sure Ty had a handle on the baby question. "Where does who come from?" I cautiously responded. "Lollipops," Ty stated, holding a sticky, purple lollipop an inch from my face. I launched into a mini-lecture comparing maple-syrup production to lollipop-making; when Ty's eyes glazed over, I decided his question could best be answered in our kitchen back home.

WHERE LOLLIPOPS COME FROM

The next day Ty and I made a batch of lollipops. He was able to observe firsthand how temperature can change ingredients (matter). The liquid mixture boils when heated and the water in the mixture evaporates, changing from a liquid to gas. What is left behind is a thick, supersaturated sugar solution. When this solution cools, it changes from a liquid to a solid. Ty came away from the activity with some tasty treats and a new understanding of an important science concept. Try this activity with your students--I guarantee some very sweet results!

MAKE LOLLIPOPS

Concepts: Temperature affects the state of matter. Heat can change most solids to a liquid or a gas. Cold temperatures can cause a liquid or gas to change to a solid.

Skills: observing, measuring, predicting, inferring, sequencing, and hypothesizing

Materials: a hot plate, a medium-size saucepan, a wooden spoon, cooking-oil spray, two cookie sheets, wax paper, a 2-cup-size clear measuring cup, a 1-cup measuring cup, wood craft sticks for each child, a candy thermometer, and a reproducible for each student

Ingredients for 24 lollipops

1/2 cup light corn syrup 1/2 cup water 1 cup sugar 4 drops food coloring 1 teaspoon flavoring, such as cinnamon, lemon, or licorice

Procedure:

1. Before the lesson, prepare a space where you can set up a hot plate so that several students at a time can look into the saucepan. Have students help you line the cookie sheets with wax paper and lay the craft sticks on the wax paper, spacing them about an inch apart. Lightly spray the inside of the large measuring cup and the saucepan with cooking oil.

2. Make a chart like the one shown on the opposite page, beginning with just the left-hand column filled out. Ask your students to think of how the items change when they are heated or cooled. Write their answers on the chart.

3. Ask students to help you use the small cup to measure the ingredients, then pour them into the large measuring cup. Note and record how full the cup is.

4. Pour the ingredients into the pot. Ask your students to predict how heating will affect the solution.

5. Heat the solution 10 to 15 minutes, until it reaches 300 [degrees] F on the candy thermometer. (As a safety measure, have students stay at least a foot from the saucepan.) While you are stirring, students can record their observations on their reproducibles.

6. When the liquid is ready, carefully pour it back into the large measuring cup. Have students compare the amount of liquid they have now to the amount they began with.

7. Pour a small amount of the liquid--while it is still hot--onto the top inch of each craft stick. When the lollipops have cooled, peel them from the wax paper.

8. While students enjoy their lollipops, discuss the observations they recorded on their reproducibles. Talk about states of matter (solid, liquid, gas) and how temperature affects matter. Ask: Which states of matter did you observe during the activity? Looking back at the chart you made in step #2, which of these are examples of a change in the state of matter?

ACROSS THE CURRICULUM

Math: Have students draw and label their favorite kind of lollipop--from Sugar Daddies to orange pops--on a small piece of paper. Invite them to use their drawings to make a class bar graph of their choices. Use the bar graph to practice various math skills.

Language Arts: Invite students to write lollipop poems in the shape of lollipops. (For more about writing shape poems, see November/December 1994 Instructor, page 60.)

Social Studies: Ask students to research the history of making maple syrup. What regions are known for maple syrup production? Have them compare the process to lollipop-making.

               Changes When Heated           Changes When Cooled

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