FUN-ky Science

I have found that children are really interested in any science activity that explores the world of the gross and disgusting. Recently, a group of curious elementary school teachers and I stepped boldly into this world. Our mission: answer the age old question - Why do feet stink? Yes, this was grossology at it's best!

So...why do our feet develop that marvelous odor? Well, it all boils down to sweat and bacteria. Your foot is one of the sweatiest parts of your body. There are more than 250,000 sweat glands on each of your feet. That's a lot of sweat. In fact, one foot can produce more than a pint of sweat each day! Now, sweat doesn't really smell. It's basically just salt water. However, there are bacteria that enjoy eating sweat, and the human body has more bacteria than it has cells. For these bacteria, our feet are basically a sweat smörgåsbord! Like most other organisms that eat, bacteria also excrete waste. That funky foot smell is actually the odor of this waste.

In an effort to better understand the science behind foot odor, we decided to grow some of the bacteria from our feet. Bacteria are so small that about 1,000 could fit on the head of a pin. However, if you grow enough of them, you can see the group (colony) with the naked eye. This is a simple activity. Easy to do and plenty of opportunities to experiment. Here is what you will need:

• Petri Dishes (one for each child is good)
• 1 Box of Unflavored Gelatin (you can find it at the grocery store)
• Cotton Swabs (one or two per child)
• Beef Bouillon Cube (optional)
• Stove or Hot Plate
• Clear tape
  

Here is what you do:
Instead of sweat, the bacteria will eat and grow on agar. The following instructions make enough agar for six petri dishes (adjust the measurements for your needs).

1. Add one tablespoon of gelatin to one cup boiling water. If you have a beef bouillon cube, add it at this point. Stir the mixture until the gelatin and cube dissolve completely.
   
2. Pour a thin layer of the liquid in each Petri dish and cover quickly to avoid contamination.
3. Allow the gelatin to cool and set (30 minutes)
   
4. Using the cotton swab, each student should swab the bottom of their feet (about a two-inch square area). There is now bacteria on the cotton swab!
   
5. Now, we need to put the bacteria in the Petri dish. Open the Petri Dish and gently make streaks on the plate’s surface (make sure you use the swab with the bacteria on it). Use firm, but gentle pressure.
   
6. Discard the Q-tip.
   
7. Cover the Petri dish and tape down the cover with clear tape.
   
8. Store the Petri Dish in a dark, warm, and dry place (a copy paper box works well).

Over the next five days, check the dishes and record the changes to the surface of the Petri dish. After a short time, you should begin to see small colonies of bacteria growing. When you have finished the activity, place the used Petri dishes in a plastic garbage bag and dispose of them in the garbage.

This activity can be extended beyond stinky feet. For example, students can collect samples of bacteria from their mouths or hands. In fact, you can grow different types of bacteria in the same Petri dish. Students can also collect bacteria from places in the classroom or school (e.g. the doorknob, the toilet seat, the desk). Before beginning the activity, ask students to guess which areas of the classroom/school will have the most bacteria. After collecting their ideas, allow the students to collect and grow samples of bacteria from these areas. There are plenty of ways to make this experience valuable, relevant, and fun for your children! The next time somebody wants to know why her/his feet smell, you and your children will know the answer.

Five Myths About Girls In Science

I spend a lot of my time researching the factors that influence the participation or lack of participation of certain groups in science. Historically, science, mathematics, and engineering have been considered by the masses to be the realm of men. In fact, most of our images of the scientists are male.

Quick, name five scientist. How many of them were women?

The National Science Foundation recently published an article on its website concerning five myths about girls in science.

1. Myth: From the time they start school, most girls are less interested in science than boys are.
2. Myth: Classroom interventions that work to increase girls' interest in STEM run the risk of turning off the boys.
3. Myth: Science and math teachers are no longer biased toward their male students.
4. Myth: When girls just aren't interested in science, parents can't do much to motivate them.
5. Myth: At the college level, changing the STEM curriculum runs the risk of watering down important "sink or swim" coursework.

The article is a quick read and very enlightening. If you are an educator who works with girls, I suggest that you take a moment to read it. Actually, everybody should take a look at the article. Chances are that we all know a girl in our community, school, church, or home that has the potential to truly enjoy science.

Read the article here.