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NEW NOS TEXT FOR SECONDARY STUDENTS 
SYNOPSIS 
Oat seeds are "planted" in a particular environmental context, in the first week of the course, followed by an intensive introduction to the Nature of Science. Concurrent with that introduction, students record their daily measurements, process those data (graphically and statistically), and prepare a formal report, using sample reports as a model. Introduces the use of a simple statistical tool to measure significant differences. 
PRINCIPAL CONCEPT 
Processes in science include critical and quantitative observations limited to single variables whenever possible.  
ASSOCIATED CONCEPTS 
1. Experimental studies must use controls to assure that
the effect of a single variable is being measured 2. Biological phenomena typically vary in their expression, requiring statistical analysis for clear interpretation. 3. Hypotheses provide generalized expectations or understanding based on logic and previous experience, while predictions based on hypotheses point to specific outcomes. 4. Experiment must be a fair test or the hypothesis: results could go either way, but must match or not match the predictions based on the hypothesis, thereby supporting or weakening the hypothesis. 5. Scientific reports must be clear and detailed enough to enable accurate repetition by others. 

ASSESSABLE OBJECTIVES

1. Distinguish good and bad examples of controls, hypotheses,
predictions, and scientific reports. 2. Recognize an experiment that actually does a fair test of a hypothesis and one that does not. 3. Analyze a graph of data for what it tells us vs what it does not tell us. 4. Analyze what the statistical tTest tells us, and what it does not tell us. 5. Recognize the appropriate interpretation of different tvalues at different levels of confidence. 6. Distinguish "significantly different" from "not significantly different." 
MATERIALS 
See Oat Seed Lab: Teacher Notes (PDF) for details. Also, for the teacher rationale and the experimental rationale to share with students, be sure to read the Teacher Rationales. 1. Fresh oat seeds (Avena sativa), plastic vials, masking
tape, marking pens, forceps, paper towels. (Plastic vials could be old and cleaned vials used for fruit fly studies.) 
TIME 
About 30 minutes to set up, and 510 minutes a day to measure when shoots appear  for about 5 days. 
STUDENT HANDOUTS

Oat
Seed Lab: Instructions (3 pages) Results (two Data Tables  1 page) Statistical Significance  tTest: Information (2 pages + Data Sheet) Statistical Analysis: Sample Data Sheet (add to Stat. Signif. packet) Sample Research Report (Including Discussion Format and 2 Sample Discussions (4 pages) 
TEACHING STRATEGY 
See Oat Seed Lab: Teacher Notes (PDF) for details. Also, for the teacher rationale and the experimental rationale to share with students, be sure to read the Teacher Rationales. This twoweek experiment is intended to be a guided model of a simple investigative study using a control set, providing detailed instructions with sample charts, statistical analysis, and examples of final reports. This should serve as an example for any future investigative studies that could be undertaken by the class or individual students. Set up in the first week of school, it also serves as a vivid experience of a biological process (germination and growth) that many students may have never had, providing a point of reference in later class work in Biology or Life Science. With growth measurements taking only several minutes each day, other lab activities can be done concurrently, labs that illustrate other key components of the Nature of Science that can be selected from the Nature of Science index on this site. 
PROCEDURES
Click for More Images 
1. Optional, day before or day of lab, introduce use of metric ruler to measure in mm and cm. See Meaningful Metrics with Dramatic Demos 2. On the first Wednesday or Thursday of the semester, have materials 14 available to all students. Introduce the rationale for doing this study (read from the Problem and Background in the Sample Report). Demonstrate and describe procedures as described in Teacher Notes. Students prepare the vials, plant the seeds, add fluids, and place them in the wood blocks. 3. Friday: have students add more water and test solution (each to level just below lower ends of seeds). Hand out the Instructions Packet to read for homework, insert in notebook, and bring each day. 4. First day of measurements (Monday following planting):
provide metric ruler and Results sheet (with data
tables) for each student. Demonstrate how, where to measure,
and where to record. 7. After the next weekend, you may continue measuring for
a few days, unless lots of seedlings are so long that they are
bending and breaking. When that happens, students make final
measurements, and clean up the vials: pour out the fluids,
pull out the wet towel with the seedlings and discard into wastebasket.
Rinse the vials with water, and place upside down to drain and
dry in wire baskets. 10. Provide computers with Excel spreadsheet for students to input their last day's data and get their tTest results. Hand out Sample Research Report packet to read for homework. This provides instructions and models for the formal report that each student must prepare, using their team data and the collective results obtained by the other teams. This can be expedited by asking one person from each team to raise hand when you ask for "who got... significantly faster growth of experimental seeds," "significantly slower growth of experimental seeds," or "no significant difference of growth in the two vials." Place the tally results on the board or overhead for each student to record the numbers of teams reporting each kind of result obtained in the class. These data must be included in the report as being from a larger, and therefore more reliable, sample size. All data taken together (team data and class data) must contribute to the discussion and statement of conclusion. 
ASSESSMENT 
See Assessable Objectives for focus of assessment. 
EXTENSIONS 
& VARIATIONS 
Statistical Significance and using the tTest
Online
tTest calculating program
http://graphpad.com/quickcalcs/ttest1.cfm
Explanation and a datainput online solution
http://www.physics.csbsju.edu/stats/ttest.html
Includes procedure and a ttest table:
http://helios.bto.ed.ac.uk/bto/statistics/tress4a.html
Explains, shows diagrams and formula:
http://www.socialresearchmethods.net/kb/stat_t.htm
Experimental Biosciences (explanation, formula,
table):
http://www.ruf.rice.edu/~bioslabs/tools/stats/ttest.html
ATTRIBUTIONSSome of the ideas in this lesson may have been adapted from earlier, unacknowledged sources without our knowledge. If the reader believes this to be the case, please let us know, and appropriate corrections will be made. Thanks. 
Created by: Larry Flammer, 1966 
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