Microbes in Our Schools: Integrating Microbiology into an Elementary Curriculum
Here are some additional experiments that we have performed with elementary aged children, as well as with elementary school teachers. Many of these have been adapted from ASM/Foundation for Microbiology's Microbial Discovery Workshop Curriculum, and I will try to give proper credit when possible. In most cases I have adapted these experiments and activities to make them suitable for elementary aged children.
I. Pandora's Box (also known as Microbial World Discovery Box): This is a great introductory activity into the world of microbes. I learned it at a Microbial Discovery Workshop - I have chosen materials that would be understandable to elementary aged kids.
Show the kids an interestingly decorated box that contains unknown materials. This is a great place to put in some Greek mythology and tell them that this is Pandora's box. Ask if anyone knows who Pandora is, and what was inside the box she opened. You'd be surprised - one third grader knew more about Pandora than I did!
Explain to the kids that Pandora's box contained all the ills of the world - but it also contained one other thing. Try to get them to figure out what it was (it contained hope). Now, open the box and let each group of students pick out one item. Ask each group to brainstorm amongst themselves and come up with one way in which their item pertains to microbiology. The following is a list of items (some taken from the original, some of my own design) that I would find suitable for elementary-aged kids. The items will vary depending on the age of the kids. My explanations are included for each item.
- Empty yogurt container: Formation of yogurt from milk relies on actively growing cultures of specific bacteria. If the kids can read, they should be able to find the label on the package that says "live and active cultures". (FYI, the bacteria used are Lactobacillus spp. and Streptococcus thermophilus)
- Blue cheese of some type: Most cheeses that are aged have bacteria or fungi added to them - the type of bacteria/fungus determines the flavor of the cheese. In the case of blue cheeses, you can explain that the blue vein is actually made of blue mold (fungus) which is a particular Penicillium spp.
- Swiss cheese: Where do all those holes come from? They're the result of fermentation by bacteria (Propionibacterium shermanii) which produces a lot of gas as a by-product - and therefore holes in the final product! The bacteria also give the cheese its characteristic flavor.
- Empty container of antibiotic tablets: Most kids will tell you this is what's used to treat bacterial infections - and that certainly is true. But more importantly, most antibiotics are derived from natural products of fungi or bacteria that are used by these organisms to kill their competitors. A perfect example that I think Dr. Waksman will appreciate is the antibiotic streptomycin, produced by the bacteria Streptomyces griseus and discovered by Dr. Waksman's father!
- Bread: most breads are made with yeast, which is a type of fungus. The yeast (Saccharomyces cerevisiae) ferments, producing gas as a by-product which results in the bread rising.
- Split peas or peanuts: These plants are members of the legume family. Legumes rely on bacteria in the soil that attach to their roots and help the plants grow by fixing nitrogen gas so the plant can use the nitrogen. The bacteria are called Rhizobium.
- Vinegar: Vinegar is made when a type of bacteria (Acetobacter spp.) ferment ethanol (alcohol) into acetic acid (vinegar).
- Coffee beans: When these beans come off the tree, they are coated with a pulp and surrounded by a thin skin. Yeasts are use to ferment and help destroy the pulp, so the beans can be more easily cleaned and dried.
- Rubber or other toy whale: Some whales have large "rumens" almost like cows, which help them digest their food. These rumens contain large numbers of bacteria, yeasts, and protozoa. Recently scientists have discovered that some of the rumen bacteria can break down toxic compounds, such as crude oil or TNT. Scientists are trying to grow these types of bacteria to help find new ways to clean up the environment.
- Picture of a hot springs, such Old Faithful: Scientists have found bacteria that can live at very hot temperatures. They are using enzymes made from these bacteria to help them do experiments that would not otherwise be possible.
- There are probably other examples that can be used, but these seem to work well for elementary aged students.
IMPORTANT: It is likely, when children (or adults for
that matter) are asked what these objects have to do with microbiology,
that they will offer answers that put microbes in a negative light. For
example, they might say "If you touch a whale (or if you eat bad cheese
etc.) you could get sick." Point out to the class that in all the
examples of objects from Pandora's box, microbes served a USEFUL
purpose. Next, try to relate this back to the story of Pandora's box,
and the idea that, even in the midst of bad things, there was hope.
This seems to have a very powerful impact on kids - or adults.
II. Using Microviewers - again, from Microbial Discovery Workshops
Unlike microscopes, microviewers are relatively inexpensive (usually around $10) and easy to use, even for fairly young children. They typically magnify things around 30X, which of course won't let you look at bacteria, but does open up a whole new world to young children. It really emphasizes to them the idea that large things may be made up of many small, unseen components.
At its simplest, the microviewer can be used in a relatively unstructured way as a magnifying glass to look at whatever the kids want.
However, one excellent use is to begin to get children to learn how to put things into categories based on different properties. This goes along with the idea that there are many different types of bacteria, each with their own unique characteristics, that can be differentiated based on specific criteria.
- Bring in pieces of the Sunday Comics (it is important to have
colored comics). Have each student pick out one comic strip. For
younger children, you can have them draw on a piece of paper all the
different colors they see in the comic strip - older kids can write them
down. Next, tell the class to find an area in their strip that has a
certain color - green for example. Tell them to use the microviewer to
examine that color. Have them draw out what they actually see. They
will find that, what appears to the naked eye to be a single color is
actually an area composed of tiny dots of many different colors! For
example, green might be made up of mostly blue and yellow dots, with a
small number of red dots. Do the same thing for different colors:
orange, yellow, black etc. For younger children, this can be a start to
discussing how different colors are combined to make other colors.
- Learning how to "key" unknown items with the microviewer. This is a
great way to teach children how to use a logical, step-by-step reasoning
process to identify unknowns. The following is an example of items you
can use - you can vary the type and number of items, depending on the
Example key to microviewer specimens a. Substance is white in color If yes go to letter d If no, go to letter b b. Substance is brown in color If yes go to letter g If no, go to letter c c. Substance is black in color If yes go to letter j If no, go back to a d. Substance is composed of distinct crystals If yes go to letter f (look in microviewer) If no, go to letter e e. Substance is powder-like Crme of tartar All the following must be viewed with the microviewer f -1 Crystals are small distinct cubes Salt f -2 Crystals are small irregular-shaped cubes Granulated sugar f -3 Crystals are large and irregular Laundry detergent g. Substance is composed of distinct crystals If yes go to letter h If no, go to letter i h -1 Crystals are very large Raw sugar h -2 Crystals are small and clumped Brown sugar i. Substance is small and irregular shaped Cinnamon j -1 Substance is round to kidney bean shaped Poppy seeds j -2 Substance is irregular shaped Black pepper
This is an example of a simple key. You can make it more complex by adding more variables. For very young children you can simplify it even more by having pictures and colors instead of words (or better yet, accompanying words).
- If using a key is too complicated for younger children, you can have
them identify objects based on what they look like under the
microviewer. Have pictures of different objects as they would appear in
the viewers and a list of the different objects you are using. Ask the
kids to try to match the object with what they think it will look like
under the viewer. Next, let them take a look and see if their guesses
were accurate. You can even ask them to explain WHY they think a
particular object will look a certain way when magnified. Good items to
use include: salt; hair; feathers; steel wool; gauzy types of cloth;
sugar or other crystals. Use your imagination!
III. A different handwashing experiment: Caught Red-Handed! This comes from an ASM collection of activities called "Microbeworld Activities".
It works VERY well with younger children - but even adults are amazed at what it actually takes to thoroughly wash your hands!
Talk to the children about the importance of handwashing, and ask them how well they think they wash their own hands.
The entire activity can be downloaded from the ASM site. However, for younger children, I will outline the activity with some modifications:
- Have the kids work in groups of 2. Have one child put on a smock, apron, or something to cover their clothes initially. Then blindfold that child. The other child will be the "timer" and "recorder".
- Pour a given small amount of washable paint onto the blindfolded child's hand and have them smear it all around the hands - the timer can help with this.
- Allow the paint to dry. This should only take a minute or two.
- Now, have the blindfolded individual wash their hands in a sink for a given amount of time - which the timer will keep track of.
- With young children, four different time points are just too many. The best compromise is to have the individual wash for 5 seconds, then have the recorder draw a diagram of where the paint remains.
- Next have the blindfolded child wash for twenty seconds and repeat the recording. Now have the child take off the blindfold and see how clean their hands are after twenty seconds of washing.
- Make sure the kids change places and repeat the experiment.
To add another dimension, you can explain that most hospitals require (or at least suggest) a minimum of 20 seconds for handwashing. This is actually quite a long time. Get the kids to come up with a song that takes about 20 seconds to sing, and use that to judge the length of time they wash their hands. For example, a veterinary student who was a former nurse told me once that they used "Yankee Doodle" in their class!