An Introduction to Inquiry and Field Work Using the Winogradsky Column

 

Jared Fox

Frederick Douglass Academy III, Bronx

 

Summer Research Program for Science Teachers

August 2007

 


   

  

              


 

Building a Winogradsky Column: An Educator Guide With Activities in Astrobiology

 

Target Audience: Secondary Life Science


Objectives: Students will be able to...

  1. Make predictions about their Winogradsky column and inferences about the growth of the organisms within.
  2. Carry out sample collection and explain the need for scientific field work.
  3. Take measurements and interpret data over an extended inquiry activity.
  4. Write a formal lab report and present the interpretation of data.

 

What's a Winodradsky Column?:

A Winogradsky column was created by a Russian Scientist named Sergei Winogradsky in the late 19th century.  The simplified version that you can create with your students in your classroom will provide an environment in which to explore the microbial world.  Over a course of a few weeks and even an entire school year your students can make observations and inquiries into the bacteria that are growing at various levels of their column.  Due to varying concentrations of light, oxygen, and nutrients you and your students will observe the formation of various microbial colonies observable through the colors that appear at different levels throughout the column.

 

Teacher Instructions:

Part I: Background

Do Now: “What is a microbe?”  Record student responses on a KWL chart and complete “W” column following responses.

 

Materials Needed: 

 

At this time teachers may choose to introduce background knowledge of microbes/bacteria depending on their classes readiness levels, but this activity works just as well as pure inquiry.

 

See Building a Winogradsky Column: An Educator Guide With Activities in Astrobiology for detailed activities and lessons for introductory material.

 

 

Part 2:  In the Field - Collecting Soil Samples

 

Materials Needed:

 

 

Soil samples can be collected from anywhere, but those from a water source (freshwater or marine) should be given preference.

 

Sample collection can be done by the teacher alone, but it is recommended that students accompany the teacher so the teacher can introduce their students to field work.

 

In the field, if time allows, have students make observations and create drawings of the area in which samples are being collected (See student lab packet).  The teacher may also use this time to explain the types of science that is done using field work, particular mention may be made of Jane Goodall’s observation of chimpanzees.

 

 

 

Part 3:  Building the Winogradsky column

 

Materials Needed:

 

Into each soil collection bucket add

·         Egg yolk, newspaper, and chalk (approx. 1-2 % of soil volume of each substance).

·         Stir as needed

·         Be sure to add enough water from the source to ensure a creamy consistency.

 

While doing this the instructor may wish to lead a discussion.

 

Sample Discussion Questions

 

Adding Soil

·         Have one student from each group fill their bottle approximately 90% full of soil.  It may be helpful to have funnels available or students can cut the top off of the bottle.

·         Tap the bottle periodically to ensure an even distribution of soil.

·         Add enough water to cover the soil (approx. 2 cm)

·         Cover the bottle with the cap or plastic wrap if the top has been cut away.

 

 

Part 4:  Column Observations

 

Materials Needed:

 

Once students have created their columns they should complete the next section of the ‘Student Lab Packet’ – Making observations and hypotheses.

 

Note:  Measurements should be ongoing over a course of at least 4 – 6 weeks, after this time the column will begin to change colors at various soil levels depending on the type of bacteria growing at each depth.  http://www.woodrow.org/teachers/bi/2000/Winogradsky_Column/winogradsky_column.html will provide a detailed description of microbial growth. 

 

Each student should make observations about their column paying close attention to coloration of the soil at each level.  It may also be useful to have students quantify some of their observations like bottle weight and soil/water height. As enrichment teachers may want to have students create a wet mount of the water in their columns.

 

Observations should be made weekly and students should record their observations on a new data sheet.  During this time teachers may want to create a digital record of student columns.

 

Part 5:  Column Placement

 

Materials needed:

 

Students should decide as a group where they want to place their column within the classroom.  Columns can be grown in the dark or under a light bulb (40 – 60 w).  It is not recommended that columns be placed in direct sunlight.  Once students place their columns they should record where they placed the column and create a hypothesis and reasoning behind their placement in the Student Lab Packet.

 

Project Completion

 

Following the weeks of observation and data collection teachers may choose to have students end their Winogradsky projects in a variety of ways. These include, but are not limited to the following.