Experimentation is the linchpin of a successful science classroom—and it makes learning a lot more fun. “Learning science requires repetitive exposure to what it’s all about,” says Harry E. Keller, president of Smart Science, which provides schools with online science labs that use real experiments. “It’s not about learning the stages of mitosis or that force is mass times acceleration. It’s about a special way of thinking that leads inevitably to what Carl Sagan called a ‘baloney detection kit.’” To help train your students’ scientific minds, try some of these memorable science experiments.
Dissect a Flower
To help students learn the parts of a flower, compare male and female anatomy, and determine how fertilization works, have them dissect a flower as an easy, inexpensive, hands-on project. Provide each student or team of students with a gladiolus or another flower with easily identifiable parts. Show students how to use a scalpel to carefully make a vertical incision to open the flower, and provide pins for them to pin their flowers open for study. In addition to discussing the parts of the flower they are observing, ask students to draw a picture of the pinned-open flower, and label its parts and measure the lengths of the pistil, filament, anther, and stamen. Create a class chart, graphing the lengths of each flower’s parts, and discuss why certain parts might be longer or shorter and how those measurements might aid in fertilization.
Measure Your Water Usage
Ask students to keep a diary of their water consumption over the course of a weekend, tallying the number of times they use the restroom, wash their hands, and so forth. When they return to school, have them multiply their totals by the average number of gallons each use consumes. Discuss how water usage and availability differ worldwide (check out Cornell University’s excellent classroom
curricula around water and development in South Asia; search “Cornell, to sustain life”). To emphasize scarcity and use, Anthony McClellan, a seventh-grade science teacher at Moses Brown School in Providence, Rhode Island, had each of his students carry the average amount of water they consumed in a day around the school track for 1 mile. “The kids found that carrying 5 gallons, approximately 45 pounds, of water a mile is quite a challenge,” McClellan says. “Roughly 20 percent of the [world] population does not have access to clean water and needs to get it from a public supply. Our kids hopefully developed a bit of empathy.”
Does Air Have Weight?
To answer this question, take two balloons inflated to equal size and, with two strings of equal length, tie the balloons to opposite ends of a wooden ruler so that the balloons can dangle below the ruler. Attach a third piece of string to the middle of the ruler, and tie its other end to a table or support rod so that the ruler hangs parallel to the floor. With a needle or other sharp object, puncture one balloon, and ask students to journal about or discuss what happened and why. Students should be able to figure out that the ruler tipped to the side of the still-inflated balloon because of the weight of the air inside. The empty balloon is lighter because its air escaped into the room.
Find Out the Color of Money (and Nails)
Discuss the chemical processes of oxidation and reduction, and then demonstrate the concept with this experiment: Mix 1/2 cup of vinegar and 1 teaspoon of salt in a glass dish. Drop about 15 pennies into the mixture, and leave them there for 10 minutes. (Older pennies—pre-1982—work best, according to the Layers of Learning curriculum.) Remove the pennies and, without rinsing or rubbing them, lay them on a towel to dry. Then place a non-galvanized iron nail into the vinegar mixture. Come back in 30 minutes: The pennies will have turned blue and the nail will have turned brown. Explain how the vinegar and salt speed up the oxidation of the pennies; oxidized copper leaves the blue color. The iron in the nails is reacting with the copper ions left in the vinegar solution, reducing the iron and oxidizing the copper. This process creates a brown copper coating on the nail.
Analyze a Bloody Crime Scene
Engage your middle school students with your own version of CSI. Lisa Iskra, a seventh-grade science teacher in Wilkes-Barre, Pennsylvania, teaches a forensic science unit packed with hands-on projects in which students analyze evidence collected from a make-believe crime scene. The testing includes blood analysis, fingerprinting, hair analysis, DNA fingerprinting, and blood spatter analysis. Students can also perform other tests, such as chromatography and pH analysis, “depending on the ‘evidence’ left at the crime scene,” Iskra says. The unit, which incorporates biology, chemistry, and physics, culminates with a prime suspect being tried at a mock trial event using the evidence collected and analyzed by the students. Search for “forensic science lesson plans” to find reliable lessons from sources such as thinkquest.org and PBS.