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Etiolation Study

Title

The Effect of Darkness on the Growth of Pinto Beans

Author(s)

David Kang

Question

What is the effect of darkness on the germination and growth of pinto beans?

Standards

Structure and Function in Living Systems

6. The anatomy and physiology of plants and animals illustrate the complementary nature of structure and function. As a basis for understanding this concept:

a. Students know plants and animals have levels of organization for structure and function, including cells, tissues, organs, organ systems, and the whole organism.

b. Students know organ systems function because of the contributions of individual organs, tissues, and cells. The failure of any part can affect the entire system. 

Investigation and Experimentation

7. Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept and addressing the content in the other three strands, students should develop their own questions and perform investigations. Students will:

a. Select and use appropriate tools and technology (including calculators, computers, balances, spring scales, microscopes, and binoculars) to perform tests, collect data, and display data.

b. Use a variety of print and electronic resources (including the World Wide Web) to collect information and evidence as part of a research project.

c. Communicate the logical connection among hypotheses, science concepts, tests conducted, data collected, and conclusions drawn from the scientific evidence.

d. Construct scale models, maps, and appropriately labeled diagrams to communicate scientific knowledge (e.g., motion of Earth’s plates and cell structure).

e. Communicate the steps and results from an investigation in written reports and oral presentations. 

Experimental Design

Before the experiment, there should probably be a discussion or a lesson on germination and the requirements for plant growth. After the discussion, students need to write a hypothesis statement about the effect of darkness on germination and growth of beans. Then they should set up their experiment by creating two groups of plants. One batch of beans should be kept in darkness for the duration of their growth. The other set should be kept in light. Students need to observe and record the growth of the main shoot of the beans for both groups.  Then they will compare the two groups to determine the validity of their hypothesis.

Independent variable

Presence of Light

Dependent variables

Rate of Growth

Series

N/A.

Constants

  • Level of Water. 
  • Temperature.
  • Air content.

Materials

  • paper towels  
  • newspaper
  • clear plastic cups or glass beakers
  • pinto beans
  • ruler
  • painter's tape
  • marker
  • digital camera

Procedures

  1. Wet two paper towels then line the walls of a large beaker with the towels. They should stick to the glass.
  2. Fill the core of the beaker with a crumpled sheet of newspaper. The newspaper will hold the wet towels in place.
  3. Pour water into the bottom of the glass until it is about 2-3 cm. deep.
  4. Now "plant" the beans between the glass wall of the beaker and the wet paper towels. Place them turned in different directions.
  5. Use a glass-marking pen to number your seeds. (Or alternatively, cut painter's tape into tiny piece for numbering).
  6. Record this information in lab journals.
  7. Repeat #1-6 with a different set of beans.
  8. Place one beaker in darkness (inside cabinet or closet will do) and the other near a light source (window or plant lamp).
  9. Record qualitative observations and growth of the main shoot (in millimeters or centimeters) daily in lab journals.

Sample data and graphs

Bean Data



Bean Data

.

Photographs and Movies

Etiolation Photos

References

University of Arizona Germination Lesson Plan

Seed Germination Experiment from ASU

Etiolation article


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