Petri Dish Science Projects

Science activities with petri dishes provide fun and education.

Students at all levels enjoy learning about science and how to use laboratory equipment. The petri dish, which is a flat glass or plastic dish with a cover, can be utilized numerous ways in science projects. Students can learn about everything from growing and viewing bacteria to seed germination and more.

Bacteria Around the Classroom

Draw a squiggly line in the agar with the sampled material.

Students can work in pairs or small groups for this scientific investigation. Prepare petri dishes with agar; some petri dishes come pre-prepared or consult the Resources for some safe ideas. Students moisten clean cotton swabs and rub them all over various classroom objects to collect the invisible bacteria samples; some areas to test are computer keyboards, desk surfaces, phone receivers, bathroom sinks, door handles, calculators, toys and windows. Lightly draw squiggly lines in the petri dish agar with the swabs and cover the petri dish with its lid. Label the dish with the sample name and seal it inside a plastic bag. Place the petri dishes in a warm, dark place and check back in a week to see what is growing inside. Do not open the dishes once material has grown.

Hypothesis and Results

Students learn about making predictions, designing experiments and recording results.

Students learn about making a hypothesis or prediction and designing an experiment to test it. Begin the activity by brainstorming a list of questions regarding bacteria. For instance, students may wish to discover things like how fast bacteria grows, the effect of antibacterial solution or soap on bacteria growth, whether generic or brand name antibacterial solutions work better, the effect of temperature or light on bacteria growth and the effect of different nutrients on bacteria growth. Have students write down their question and hypothesis; prepare petri dishes with bacterial samples similar to the previous project in Section 1. Discuss results and experiment methods when samples are finished growing.

Seed Germination

Petri dishes can be used to grow bigger things than bacteria.

Students can observe the effect of temperature on the germination of seeds. After washing hands thoroughly, students cut rounds of paper towels to fit easily in the bottom of the petri dishes and moisten them until the towels are saturated with water. Using tweezers, students gently place 20 alfalfa seeds in each petri dish. Seal the dishes and label them one through ten, stacking them so dish 1 is on the bottom and 10 is on top. Make predictions about what will happen in your science journal. Stack the petri dishes in groups of ten and place them on top of the teacher-prepared hot surface. Let the dishes remain undisturbed for two days, then record detailed results and compare them to your predictions in your science journal. As an alternative to the temperature experiment, students can also use different amounts of water in each dish.

Mold in Your Room

Students wonder if mold really is everywhere.

An ideal science-fair project, students use petri dishes to test the amount of mold landing in their rooms per hour. The student will need four petri dishes prepared with a sterile agar made specifically to grow mold or bacteria (see Resources). The student opens all four petri dishes in his room at once; after five minutes, he seals the first one then labels it with the time; after 10 minutes he seals the second one then labels it; after 15 minutes he seals and labels the third; and after 20 minutes he seals and labels the fourth. After several days, the student can prepare observations about the resulting growth in the petri dishes.

References

• Steve Spangler Science: Growing Bacteria in Petri Dishes
• Free Science Fair Project: How to Count Bacteria?
• The Concord Consortium: Seed Germination Lab Work
• Langston Hughes Science Fair: Ideas for 5th Grade

Resources

• Science Buddies: All About Agar
• Home Science Tools: Bacteria Science Project Guide