Tuesday, February 26, 2019

Germs - Elementary STEAM Program

Germs STEM Program,

February is usually the peak of flu season, so I figured what better time for a STEAM program about germs? I have a MS in microbiology, so this was right up my alley! We talked about different kinds of germs, observed which surfaces in the library had the most bacteria and fungi, did hands-on activities to explore how easily germs are spread and learn proper hand-washing, and observed bacteria growing on agar plates as well as under the microscope. We also talked about how most microbes are relatively harmless, and some are even beneficial.

Ages: 5-10

Time: 1 hour for program, plus additional prep time

Number: No more than 24

Budget: $40 (assuming microscope & prepared slides can be borrowed & UV flashlight is purchased)

  • 10 LB agar plates 
  • 10 sterile swabs (ours came in a set with the plates above)
  • sterile water (bottled water will work)
  • Sharpie
  • tape
  • glitter, preferable more than 1 color
  • Glow-Germ gel (2oz bottle was more than enough for 15 people)
  • UV flashlight
  • balloon
  • confetti/hole punches
  • thumbtack or sharp skewer
  • Microscope & prepared slides of bacteria (optional, we already had one, but you could possibly borrow from a school, or just look up photos online to show)


I started off by asking them what germs were, and most knew it was something that made you sick and some knew they were microorganisms, bacteria, or viruses. I had a short PowerPoint with a few pictures of different types of germs (bacteria, viruses, molds, yeast, protozoa), including the 3 shapes of bacteria (bacilli, cocci, spirochete), and a few different viruses. 

We talked about how "germs" are specifically the ones that make us sick, and that many microorganism are harmless or even beneficial, like the bacteria in our gut or those used to make yogurt and cheese, or yeast to make bread or adult beverages. I also showed them the very scary looking bacteriophage, and explained how it was harmless to us and actually infected bacteria, so germs can get germs, too! 

Then I showed them a photo of bacteria growing on an agar plate, explaining each colony developed from a single bacterium, and pointed out the differences in color, texture, and shape. Then we were ready to start the first activity.

Activity #1 - Environmental Testing

Four days earlier I took samples from various surfaces in the children's department by dipping sterile swabs in sterile water, rubbing them on a surface, then rubbing it across the entire surface of an agar plate, rolling it as I did to get everything. Each plate was labeled, then incubated inverted (so condensation does not drip onto plate) for 48 hours at approximately 80 F checking growth at 24 & 48 hours. [One plate was just streaked with the sterile water to serve as a negative control.]

[I rigged up an incubator with a spare aquarium I happened to have and borrowed my gecko's overhead ceramic heat lamp & thermostat. If it had been summer, I could have just put them in a box in the garage. If you have to incubate at room temp, allow for 2 extra days.]

I explained the prep to the participants, and gave them a list of the surfaces tested and asked them to think about it, and rank them from what they thought would have the most bacterial/fungal growth. The surfaces were: 
  1. negative control
  2. a picture book
  3. a chapter book
  4. the children's service desk
  5. a plastic apple from the play kitchen
  6. keyboard & mouse from one of the kid's computers
  7. middle shelf of the Early Readers
  8. bathroom door handle
  9. button on hand dryer
  10. toilet seat
2. After everyone had marked their choices, I showed a photo of the plates at 24 hours, noting how similar all the colonies looked, then 48 hours, noting that differences in size, color, textures were now apparent, and many new tiny colonies of slow-growers had shown up (#1, the negative control is not pictured). Click on any image to see full-sized.

Germs STEAM program, Library program

So, to my surprise, the shelf had the most growth, and the books had relatively little! I was very surprised by the books. The shelf was closely followed by the computer keyboard/mouse and play food, which I did expect. While it might seem counter-intuitive that the bathroom surfaces were some of the cleanest, our custodian cleans and disinfects it every morning (I sampled at the end of the day).

Now, don't let this freak you out! In reality, these are all very low numbers and in all likelihood are mostly harmless bacteria and molds that are to be expected in the environment.

Activity #2 - Simulating Germs Spreading from a Sneeze

We talked a bit about how germs are spread, and they mentioned sneezing and coughing right away, for which I did a fun simulation. First, prior to the program I had punched a bunch of holes from several brightly colored scraps of paper to make confetti. Then I put the confetti inside a balloon, blew up the balloon, and tied it off.

I explained the confetti represented germs, and popping the balloon would represent a sneeze. On the count of three, we all yelled "Ah-choo!" and I popped the balloon, sending the confetti everywhere, up to about 10 feet. I told them germs from a sneeze can travel up to twice that distance! Then we talked about how to properly cover your coughs and sneezes.

Activity #3 - Simulating Germs Spread by Touch

We all know how glitter seems to spread everywhere, so I got the idea to use it to show how germs spread by touch. I pressed my hand into a flat container with glitter, then shook hands with a few of the kids, and instructed them to shake hands with the person next to them, and so on to show how germs spread from our hands, and to our hands.

They saw it spread from person to person, and I also pointed out some of it had gotten on the table. I asked them to think about what would happen if they rubbed their eye with their glitter-contaminated hand? What if they picked up food with it? What if they put their food directly on the contaminated table?

This led to a discussion of how important it was to clean food-prep and eating surfaces and to wash hands, and we talked about when to wash hands, such as after going to the restroom, playing outside, before eating, etc., and how our skin provided great protection against germs, and that germs make us sick by getting inside through our mouth, nose, and eyes. I stressed in addition to handwashing, we should keep our hand out of and away from our mouths, noses, and eyes, and not to break any bad habits like chewing on pencils.

Activity #4 - Handwashing

Glo-Germ lotion contains a pigment that glows under UV light and is difficult to wash off, so it makes a great tool for evaluating and educating about handwashing. Each person was given a dime-sized squirt of the the lotion and told to rub it all over their hands, rubbing it in until their hands were dry. Then we examined with a UV flashlight to see how it glowed.

Then they were instructed to go wash their hands really well with soap and warm water (there was one sink in our program room and the restrooms were just outside). Then we checked their hands with the UV light again. Although most showed some reduction in the amount of "germs" remaining, only a few showed a significant reduction and all still had some remaining under and around their finger nails. 

They were given the option of washing their hands again and re-checking, or waiting until the end. I think it was an eye-opening experience for some of their parents, LOL!

Activity #5 - Stations

At the end, I had three different activities they could rotate from, so everyone would have a chance to look at the plates up close and look in the microscope.

A. Our library system already owned a high school classroom quality microscope with a collection of assorted prepared slides. I put a slide of stained bacteria so they could have a chance to actually look at germs. There were also photographs of bacteria under both an optical microscope and scanning electron microscope in the PowerPoint slides.

B. I had all the agar plates out on a table *taped closed* with an assortment of magnifying glasses so they could look at them up close and observe how varied the colonies were, with various shades of white, cream, yellow, and orange; some were round, some irregular, some filamentous; some were smooth, others were wrinkled; some were wet and shiny looking, while others looked dry. (There was also a diagram showing different morphologies in the PowerPoint.) As always, click on the image to see it larger.

C. Books - I had an assortment of both fiction and non-fiction books displayed on a table that they could either look at there or check-out and take home.

How It Went:

I thought it went very well, and I really enjoyed getting a chance to return to my roots and do a little basic microbiology. I only wish I could've justified the expense of buying the selective and differential media and stains required to identify some of our specimens.

The participants really seemed to enjoy all the activities. The simulated sneeze and the agar plates from testing surfaces in the library were probably the most exciting, though they were surprised at the results; most thought the bathroom surfaces would be the worst.

I did make sure to explain that our results actually showed very small numbers of microbes, and that most of the microbes in our environment are not going to make us sick, and that it is good to play in the dirt and be exposed to things because it boosts your immunity (and as I just read today, apparently it can possibly protect against some allergies.)

One of my participants seemed to know about as much as I did, even though he was only in 4th grade and I have a master's degree in microbiology! He kept giving such precise, detailed answers that I would not expect from a child that it threw me a little bit at first. He also asked if I had any pictures of Helicobacter pylori because it was his favorite bacterium! I'm a microbiologist, and I don't even have a favorite bacterium, LOL!

Another funny comment came from one of the girls. I showed a photo of the growth from the handprint of am 8-year old child who had been playing outside, and she wanted to know if it was a boy or girl, because according to her, boys are dirtier. (It actually was a boy, btw).

And, if you want to see something really cool, do a Google search for "petri dish art"!

Also, if you'd like to do something Germ-themed for preschoolers, check out my "Don't Share Your Germs" storytime.

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