Adventures in Bacteria

Antonio Marques, the writer who brings us the "Science in Review", science blog wrote to tell me that he has recently started a Group Writing Project entitled "Science Linked: BACTERIA" which you can see at http://www.scienceinreview.com/2007/science-linked-bacteria.html He has invited myself and other science blogger types to participate in the project. What is required is that we write a post on our blog about anything Bacteria (news that involve bacteria, diseases, lab techniques, anything bacteria… if it has bacteria in it, then it’s suitable), but it must be writen in in a way that can also be understood by laymen (but of course!). After the deadline, he will collect all the links and publish them all in one post thus creating a very nice little bacteria-centric resource.

I've found a couple bacteria related activities. 

Observing Bacteria Cultures in Yoghurt (from GreatScopes.com)

Materials:

• Plain yogurt with active cultures

• Light microscope

• Slides, coverslips

• Distilled water

• Dropper

Procedure:

• Clean your slides and coverslips for dust and other particles.

• Place a very small portion of plain yogurt onto the slide, and add one drop of water. Place the coverslip on top.

• Under low power, find a section where the yogurt is pretty thin; this is where you will find the bacteria.

• Switch to high power (400X for most microscopes) for a better view of the bacteria. If you have a microscope with an oil immersion lens, it will give you an even better view of these small organisms.

• Make a sketch of your view under different magnifications.

Questions:

• How many different kinds of bacteria could you find?

• What other foods have bacteria living in them?
  
  

Sour Power (from Discovery Education)

You can kill most of disease-producing bacteria in milk by heating it to 143º F (62º C) and then keeping it at that temperature for 30 minutes. This process is called pasteurization. Today “flash pasteurization” is commonly used instead, in which milk is heated at higher temperature of 160º F (71º C) and maintained for 15 seconds. In this activity, you’ll explore how the growth of additional bacteria after pasteurization is slowed in colder temperatures.

Materials:

• two clear plastic cups
• pasteurized milk
• refrigerator

Procedure:

1. On a Monday, pour a small amount of milk in each of two cups.
2. Place one cup in a warm area, such as on a sunny windowsill.
3. Place the other cup in a refrigerator.
4. What do you think will happen to the milk in each cup over the next week? Write your predictions on the worksheet.
5. Over the week, check both cups each day and write your observations in the worksheet chart. At the end of the week, answer the final worksheet question.