Classroom and Outreach Activities

The collection of activities is meant to illustrate the incorporation of the microbial world in the K-12 community either through science courses or through community-based events and programs.  The activities come from classroom teachers and microbiologists.  All activities have been reviewed by the ASM Committee on K-12 Outreach for scientific and educational content, active learning and engagement, alignment with the National Science Education Standards, and clarity of accompanying instructions. 

Guidelines for Submitting an Activity


NEW! Putting Disinfectants to the Test

In this two-part lab, students will sample the indoor environment to estimate how many bacteria are living on surfaces, then test the effectiveness of various household disinfectants on bacterial growth. Students use RODAC petri plates to directly sample surfaces such as benches, desks, or cell phones and then can quantify the number of bacteria detected before and after cleaning with a disinfectant. They will also set up a disc diffusion assay to test the potency of household cleaners and other disinfectants against Gram-positive and Gram-negative bacteria. Intended Audience: 9-12

What Food Does Yeast Like Best?

This activity turns a classic student observation activity of yeast generation of gas into a guided inquiry lab. Rather than give the students one sugar, we give them a range of foods to taste for developing hypotheses based upon their analyses of the foods. The students then design the experiment with appropriate controls and carry it out using gas generation in a closed system with a balloon to measure yeast fermentation. Intended Audience: K-4


Quantification of Escherichia coli Contamination in Water

The lab exercise assumes basic knowledge of prokaryotes (structure, function, metabolism, and respiration) and the functions and limitations of enzymes. Building upon this knowledge and using guided prompts, students brainstorm how to create an agar on which only coliform bacteria will grow and how to differentiate between Escherichia coli and other coliforms based on their enzymes. Finally, students filter surface water and place it on media that differentiates E. coli from other coliforms using an enzyme unique to E. coli. The resulting data are used to determine if the water meets the Minnesota state standards for safe swimming or drinking water. Intended Audience: 9-12

What Microbe Are You?

In this hands-on activity, students take an online "personality quiz" where their answers to a set of either/or statements match them with the marine microbes that most closely resemble their personalities. The microbes are given fun code names to circumvent the challenge of pronouncing the microbes' scientific names. Intended as a fun way to begin or end a unit on life science, the students learn about the vast diversity and critical importance of marine microbes. Intended Audience K-8.

Bacteria That Help and Hurt Cows

This lesson introduces students to the microbial world and provides insight on their function by examining bacteria that both help and harm cows.  Although multiple bacteria inhabit the cow’s rumen, this lesson focuses on two harmless microbes; Ruminococcus and Selenomonas, which break down cellulose and starch in plant matter, respectively.  These bacteria obtain nutrients from the cow’s diet, and the cow gains energy from the products of bacterial metabolism. Therefore, these bacterial species are in a symbiotic relationship with the cow. Other bacterial species can harm cows. Such is the case with Escherichia coli, a non-ruminant bacterium that can cause the udder infection known as mastitis.  Intended Audience K-4.

Is It Clean or Just Unseen? Dirty Water and the Naked Eye

In this experiment, serial dilution of a contaminated water source is examined for turbidity and bacterial cell count. Because chemical and microbial contaminations are not always visible to the naked eye, the microbial presence will be brought to the attention of the learner by use of viable plate counts. Intended Audience: 9-12.

Quantifying Marine Microbes: A Simulation to Introduce Random Sampling

This lesson introduces random sampling, one of the key concepts employed by scientists to study the natural environment, including microbial communities. Students first learn about the abundance and diversity of marine microbes. Colored beads in a bag are then used to represent different types of microbes, with the bag itself representing the ocean. Working in groups, each student randomly samples ten "microbes" from the "ocean", and records the data. To learn about the inherent variability of random sampling, the students then compare the composition of their individual samples, their group’s pooled sample data, and that of the entire population. Intended Audience: 5-8; 9-12.

Modeling Concepts of 5’, 3’, Antiparallel and Complimentary in DNA Structure

Many students studying DNA structure do not understand or cannot fully visualize the concepts of complementarity, antiparallel, and the organization of the 5’ and 3’ ends of a nucleotide strand.  Here, a method that works very well to get students actively involved in the process of describing a DNA molecule is described.   Students themselves are used as the nucleotides in this activity.  Intended Audience: 9-12.

The RNA Decoder Ring: Deciphering the Language of Life

The DNA molecule is often and aptly compared to a written language that uses only 4 letters; A, C, G and T. The linear sequence of these letters provides information that guides the synthesis of RNA and proteins and through these products defines the characteristics and abilities of individual organisms. To assist students to understand how a 4-letter alphabet can carry coded information and how that information gets translated, we have developed a tool that students can assemble, and activities they can use to decipher the genetic code in fun and familiar ways. The tool is the RNA Decoder Ring that allows students to align the 64 codons specified by the 4-letter genetic alphabet to determine which amino acid each codon encodes. When single letter amino acid abbreviations are used, DNA sequences can be constructed that translate into amino acid sequences that spell out familiar words and phrases in English. We present activities that challenge students to decode messages written in DNA that spell out English words and phrases in their corresponding amino acid sequence. Students are also instructed how to design their own coded messages using the Decoder Ring in reverse. We also provide activities that illustrate the impact that various mutations in the DNA sequence can have on their protein products.  Finally we provide an activity that illustrates how the coded language of DNA is used in cells going from DNA to RNA to the amino acid sequence using the initial portion of the human growth hormone gene.  Intended Audience: 5-8; 9-12.

Effect of Nitrate and Phosphate Levels on the Growth of Algae

Nitrate and phosphate are useful as fertilizers in agriculture and gardening.  Nitrate and phosphate aid agricultural production by producing more abundant crops. However, since the mass production of ammonia during the 1940's by way of the Haber process, it has been noted that a phenomenon known as “nitrate pollution” may occur.  This pollution can be demonstrated by conducting this simple experiment.  This experiment demonstrates two main ideas. The first is a test of what levels of nitrate and phosphate allow for optimum algal growth.  The second demonstrates at which levels of nitrate and phosphate algal blooms may occur, causing harm to an aquatic ecosystem (Freeman, 2002). Intended Audience: 5-8; 9-12.

Lean, Mean Information Machine: Using a Simple Model to Learn about Chromosomal DNA

This lesson examines the amount of deoxyribonucleic acid, or DNA, in cells. The first part emphasizes math skills as the students determine the size of a bacterium.  Then the students are asked to decide how long the chromosome of a bacterium is compared to its length using data on known genome sequences. Next, this size differential is demonstrated using a model composed of a plastic egg and dental floss.  The learners then are given information about the sizes of other cells and their respective genome lengths and they are asked to investigate the features of one of these organisms and produce a model. Intended Audience: 5-8; 9-12.

Earth History: Time Flies, No Matter What the Scale

In this two-part activity, which uses discovery and an inquiry approach, the participants will be given cartoon drawings representing significant events in the history of the Earth and asked to place them on a timeline made of colored ribbon. Then they mathematically relate the geologic time scale to a yearly calendar. After the calculations, they return to the timeline to reassess the placement of the events. Intended Audience: 9-12.

Public Health Scavenger Hunt

The Public Health Scavenger Hunt is a playful and creative investigation of basic public health concepts for small children.  This activity leads them through a series of tasks including exploration and recognition of their surroundings, hygiene recognition, riddle and puzzle solving, and cardiovascular exercise.  Students will gain an awareness of not only their surroundings, but also their body’s actions.  By completing this activity, students will be are able to recognize direct cause and effect relationships, and their creative visual skills will be put to the test. Intended Audience: K-4.

”Build a Bacterium” Scavenger Hunt

In this activity, each student is provided with a worksheet and three index cards. Each card indicates a different cell part (e.g. LPS, capsule, DNA). Students are placed in small groups and receive a written scenario regarding a bacterium with a certain goal it must carry out.  They must work together to decide what cell parts are needed to form the basic structure of any cell as well as to carry out the specific functions required by their scenario. To “build” their bacterium they must negotiate and trade index cards with other groups to acquire their desired cell parts. Intended Audience: 9-12.

Evolution of a DNA Sequence Over Time

One of the basic requirements of evolution is variation in a population upon which selection can act.  One of the sources of variation is mutation in DNA.  These changes may or may not be reflected in the ensuing amino acid sequence of a protein.  This exercise explores the additive effects of mutation on an amino acid sequence over several generations.  The activity is also useful in that it addresses several of the components of Darwin’s theory of evolution through natural selection.  There are three separate activities, one regarding sequence change over time, one regarding selective pressure on sequences, and one regarding divergence over time. Intended Audience: 9-12.

“I Can’t Live Without You!” A Close-up Examination of Microorganisms Involved in Mutually Beneficial Symbiotic Relationships

By visiting three stations, each equipped with microscopes, slides, live materials and various supplies arranged by the teacher, the students will observe three symbiotic relationships involving microbes.  The students prepare wet mounts to observe the microbial symbionts found in the termite gut, lichen, and Rhizobium root nodules. Intended Audience: 5-8; 9-12.

Extracting DNA from a Banana

The soft flesh of a banana provides a ready source of DNA. Using a few simple purification steps in a classroom setting, students can yield loads of crudely prepared DNA. To begin, the banana is mashed in a detergent/salt solution to lyse the cellular and nuclear membranes. Cellular lysate is strained, then the solubilized DNA is cleansed with a meat tenderizer (which contains an enzyme that breaks apart proteins). Lastly, ethanol is added to generate soft, white, globs of DNA and perhaps – with careful technique – slender threads that may be wound onto a glass rod. Intended Audience: K-4; 5-8.

Natural Selection

Using a variety of beans, students will investigate how various microbes can survive and reproduce.  They will explain the effects the environment has on the sustainability of a microbial community and the adaptations they need to make for survival. Intended Audience: 5-8; 9-12.

What Makes Flatulence

In this exercise, students use a controlled environment to demonstrate the build up of gases in the large intestine. Through their observations, they will better understand the mechanisms that create flatulence (passing gas) and how microorganisms can be beneficial to overall health. Intended Audience: 5-8.

One of These Things is Not Like the Other

Using a 50X microviewer, participants will observe textiles and other materials for microscopic similarities and differences. They will construct a game board in which "one is not like the other" and then challenge another participant to decipher the unlike material. Intended Audience: 5-8; 9-12.

Outbreak! Investigating Epidemics

This activity simulates how a pathogen can spread among a population. Students will exchange paper with one another to simulate the epidemiology of tracking an infectious agent. After this activity, the students should have a better understanding of how infectious agents spread from person to person and ways to prevent outbreaks. It can be adapted to a variety of scenarios. For example, the infectious agent could be HIV or another pathogen that is spread by human contact. This activity can be used with ASM's Intimate Strangers Episode 6 video podcast. Intended Audience: 5-8.

Taste Test: Can Microbes Tell the Difference

This inquiry-based activity allows students to explore the scientific process of fermentation. During the investigation, students will be responsible for observing and explaining how yeast utilizes various forms of natural sugar and sugar substitutes to produce energy. Students will also recognize how the type and amount of food sources can directly influence the metabolic activities of living organisms. Intended Audience: 5-8; 9-12.

The Role of Microorganisms in the Ecosystem

This lab activity uses a controlled experiment to demonstrate different rates of decomposition for a variety of man-made and natural materials.  Microorganisms are ubiquitous in the environment, where they have a variety of essential functions.  Intended Audience: K-4; 5-8; 9-12.

Microbial Discovery Box

In this exercise, students examine the impact of microorganisms in our daily life and consider their applied potential. They can also conduct independent research and communicate their findings with the rest of the class. Intended Audience: 5-8; 9-12.

Pond Scum: Investigating Microorganisms

Little else can stimulate a student’s interest in biology like a drop of pond water teaming with invisible life viewed with a microscope. This activity describes two means of observing pond water other than the traditional hanging drop or temporary wet mount slide preparation. Intended Audience: K-4; 5-8; 9-12.

Taking the Mystery Out of DNA: Extracting DNA from Strawberries

Students will explore how scientists isolate deoxyribonucleic acid, DNA, from the strawberry.  The activity provides the students with a hands-on approach to DNA isolation.  They will learn how cells can be broken open and how the DNA can be separated from the rest of the cellular biological molecules.  Although students may recognize DNA as being the genetic material and that it can be used in forensics to identify a killer, most are not exposed to what DNA looks like.  This activity brings DNA to life! Intended Audience: 5-8; 9-12.