I’m re-posting this project we did two years ago, since I’m making plates today for a hand-washing experiment that the kids and I will do after school. Stay tuned!

Did you know that every surface in your home is teeming with microorganisms? Culturing microbes from your home on petri dishes lets you grow some of them as colonies  that you can see with your naked eye. You might already have what you need in your kitchen cupboard.  If not, the ingredients are readily available at most grocery stores. I demonstrated this experiment on Kare11 and you can watch it here, following the yeast experiment.

To make petri plates, you’ll need disposable containers (see below),  beef bouillon cubes or granules, plain gelatin or agar agar*, water, sugar and Q-tips. (*Agar-agar can be found with Asian groceries in some grocery stores.) **Gelatin will melt if it gets too warm, and some strains of bacteria can liquify it, which is why scientists in labs use agar to make their plates.  The idea to use agar for plates originally came from Angelina Hess, who used agar for canning food.

For containers, you can use foil muffin tins, clear plastic cups covered with plastic baggies, clear Tupperware with lids, or real petri dishes.  We’re going to use clear deli containers, so that we can recycle while we learn.  (Containers must be heat-resistant enough to pour warm agar into.)

Start by making microbial growth medium (or microbe food, as we like to call it.) Mix together:
–1 cup water  
-1 Tbs. agar-agar (OR one and one half packages gelatin, which is about one and a half oz or 12g)
–1 bouillon cube (or 1 tsp. granules)
–2 tsp. sugar

The next step requires adult assistance, since it involves very hot liquid.  Bring the mixture to a boil on the stove or in the microwave, stirring at one minute intervals and watching carefully until the gelatin or agar is dissolved.  Remove the boiling liquid from heat and cover.  Let cool for about fifteen minutes.

Pour the medium carefully into clean containers, until 1/3 to 1/2 full.  Loosely place lids, foil or plastic baggies over containers and allow dishes to cool completely.  The geltin or agar should make the growth media hard like jello.  When your plates have hardened, store them in a cool place, like a refrigerator, before using.  Plates should be used in 2-3 days.  When you are working with the plates, try to keep the lids on loosely whenever possible, so that they are not contaminated by microorganisms floating around in the air.  If you’re planning to use muffin tins, simply place them in a muffin pan, fill them with agar, and when they’re cool, put them in individual zip-lock baggies.  With other containers, put the lids on tightly once the plates harden.

When the plates are ready, shake the condensation (water droplets) off the lids of the containers and put them back on.  If you have a clear container, you can draw a grid of four sections on the bottom of the plate with permanent marker. (If using muffin tins, label each bag with the surface you are checking.)  Decide which surfaces you’d like to test.

Label your plates with the names of the surfaces you want to test.   Be sure to label the bottom of the plate since the lid will move.  You should be able to see through the agar to see your lines and your writing.  If you want to, you can label a separate plate for each surface, but we had three kids and three plates, so we made sections.  TV remotes, kitchen sinks, computer keyboard, doorknobs and piano keys are great surfaces to check.  You can even touch your finger to the plate, cough on a plate, or leave one open to the air for half an hour to see what’s floating around!  (See the photo at the top of this post for a better picture of how your plate might look.)

Rub a clean Q-tip around on the surface you want to test.  Then, remove the lid from the plate and gently rub the Q-tip across the section of the plate labeled for that surface.  If you’re careful, the agar shouldn’t break.  If it does, it’s no big deal.  When you’re done, set the plates on a flat surface with their lids loosened and taped on (do not invert them.)

Here’s what grew on one of our plates (pictured above): The large, fuzzy colonies are fungi and the small, whitish ones are probably bacteria.

See what grows! You will mostly see fungi (molds), but you may also see some tiny clear or white spots that are colonies formed by millions of bacteria.  Record and draw how your plates look in your science notebook.  Keep track of how long it takes things to grow and the shapes, sizes and colors of the microbial colonies that grow on their plates.  Sciencebuddies.org has this great page on interpreting what you find growing on your plates!  If you want to learn more about microbes, search for the words fungi and bacteria on the website cybersleuthkids.com and it will give you some great links to microbiology websites.  Microbes are everywhere, but that very few of them are harmful, and many of them are essential for good health.

Wash your hands after handling the plates, and throw the plates  away when you are done.  Remember, if you washyour hands with regular hand soap for the length of time that it takes to say the ABCs, you’ll remove most of the harmful bacteria and viruses on them.  (One side effect of this experiment is the sudden urge to disinfect computer keyboards and remote controls.)

One of the first things you learn when you do science is that experiments don’t always turn out the way you hope they will. And that’s OK. If at first you don’t succeed….

We tried to measure how far a sneeze would throw visible droplets by putting grape juice in our mouths and tickling our noses with feathers dipped in pepper. Sadly, no matter how hard we tried, we couldn’t seem to sneeze with grape juice in our mouths. Laughing so hard we spit the juice out was one unexpected outcome. We decided to try it again in the future using petri dishes spaced at intervals to avoid the grape juice problem.

Since there was no school today and it was ten degrees below zero (F), we tried throwing boiling water into the air to see if it would freeze before it hit the ground. Once again, our experimental conditions were less than perfect, and although some of the water froze into an icy cloud, the majority hit the ground with a splash. The experiment would have worked better at -20F, but it was still fun!

In a few weeks, I’ll be heading to North Carolina to attend Science Online 2013, an “un-conference” of online science communicators, writers, artists and video-makers. It will be next to impossible to choose which sessions to attend, since people will be talking about everything from writing science narrative to drawing science comics and using science to write fiction. I’ll be co-moderating a session on writing for kids with Elizabeth Preston, Editor of Muse magazine (which my 12-YO loves) and giving a short talk on why I made KidScience app.

To make the meeting even more fun, there will be a Cyberscreen film festival and an art show for participants, which inspired me to pull out my paintbrushes from college and do a quick “self portrait with microbes.” It’s been so much fun to paint again that I might go buy another canvas today and paint a “Still Life with Bacteria.”

My musician friend helped me make my silly “science song” sound amazing so I can use it on my website and for videos like the one above that I made for KidScience app.

How do you mix up science, music, film and art? Do you know any science project that can morph into art projects, like red cabbage litmus paper collages or photographing tie-dye milk patterns? I’d love to hear your ideas!  I’ll let you know about the cool things I learn and fun resources I discover at ScienceOnline in early February!

When I tell my kids we’re going to the science museum, the first thing they do is race up to their rooms to look through their rock collections. Even my twelve year old is not immune to this behavior.

Since they were old enough to talk, the three of them have been bringing paper wasp nests, quartz crystals, empty Monarch chrysalises,  fossils and other interesting finds to a hidden gem in the Science Museum of Minnesota: The Collector’s Corner.  At this oasis of curiosities (tucked away in a corner of the Collections Gallery near the mummy,) kids can trade in their stuff for points, which allow them to “buy” other amazing items. The more science they know about the item they’re trading in, the more points they get.  Luckily, they have a comfy couch for parents and grandparents to lounge on while they talk to the well-informed and friendly volunteers staffing the “Corner.”

The Science Museum of Minnesota is a great destination for those days when you don’t want to go outside, but you want to give your kids a chance to learn, explore and use their imaginations.

Every Tuesday, the Museum caters to the pre-K crowd with Preschool Playdates, where, if you purchase a regular price adult ticket, you receive a free child admission (ages 5 and under). Minnesota Children’s Museum members receive free Science Museum admission during Playdates.

These playdates include:

• Admission to the Science Museum’s exhibit galleries, packed with hands-on fun.
• Make & Take creations: Your child will use their imagination to engineer a project the museum developed especially for them!
• Special theater programs and demonstrations designed just for preschoolers.
• Parent’s guide to preschool activities and accommodations throughout the museum, including an introduction to the Collectors’ Corner trading post!

Salt lowers the melting/freezing temperature of ice, which is the solid form of water.  Here’s a fun experiment you can do to see for yourself how Sodium Chloride (table salt) makes ice melt and water refreeze on a string, allowing you to “magically” lift an ice cube from a glass of water.

Click here for detailed instructions and more about the science.

This video will soon appear on KidScience app‘s Premium version, which allows you to easily search for experiments and videos based on kids’ ages, type of science, what you have on hand, or how much time you have.

Ever wonder how much starch is in your Thanksgiving dinner?  Click here for a fun experiment that lets you test your favorite foods for starch using iodine from the medicine cabinet.

Remember to supervise small children if you do this experiment, since iodine should not be ingested! Happy Thanksgiving!

Grab an extra bag or two of cranberries and you can stir up a Thanksgiving science project: Spy Juice and invisible ink!

Click here for detailed directions.

I just put together a homemade science kit  (for a silent auction at a fundraiser) and it was so cute I had to post a picture.

homemade science kit

Click here to see a post with links to homemade science kit experiments. Love giving these as birthday and holiday gifts too! To take it up a notch, pair your science kit with KidScience app for iPhones/iPods!

Over the next few weeks, I’ll be posting some fun biology experiments, so be sure to check back in!

Everybody sing the Science Song!

Today, Target shared three of our favorite Halloween science experiments on abullseyeview.com.