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Introduction

Plant Tropism Lab DESIGN Aspect 1: Problem: How do bean plants respond to a light source? When the beans are tilted at an angle, how will the stems continue to grow? Hypothesis: The beanstalks should bend toward the light source in order to capture more light, this is called phototropism. The bean stem will likely grow upright, regardless of the angle it is tilted, and this is called gravitropism. Variables: Manipulated: influence of sunlight and gravity Responding: angle of plant growth Controlled: -same room temperature/pressure -same source of light -same amount of tilt on the beans -same source of water Aspect 2: Controlling Variables: Room temperature/pressure: keep all beans in classroom indoors, beside window Light source: sunlight from window to the right of bean plants Tilt on the beans: rotate all beans on the same day and at the same angle/direction Water: distilled water from squeeze bottles is used to water plants Aspect 3: Materials: -Kentucky Wonder beans -Stringless Green beans -Kidney beans -Pencil Pod Black beans -Golden wax beans -plastic bag -distilled water squeeze bottle -paper towel -ruler -protractor Apparatus Diagram: Diagram 1.0 Procedure: 1. Put a piece of paper towel in each of the 5 plastic bags, staple 5 pockets into each bag. Insert a bean into each pocket, one type of bean for each bag. Wet paper towel with distilled water and pin on wall to the left of a window 2. Make qualitative observations on beans growth and direction of growth as they grow 3. Measure bean's height and angle when they are taller than 3 cm, when measuring bean angle, measure 3 cm from the tip to a vertical axis. ...read more.

Middle

- - P-3 35 25 - 65 100 130 P-4 - - - 55 100 - P-5 - - - - - - H-1 10 60 40 40 80 110 H-2 - - 25 20 95 110 H-3 - - 50 0 95 115 H-4 - - - - 100 140 H-5 - - - - - - A-1 - 65 45 60 85 85 A-2 - 55 40 80 60 60 A-3 - 25 - - 70 50 A-4 - - - - - - A-5 - - - - - 20 R-1 - 90 90 85 90 90 R-2 - 90 10 95 90 20 R-3 - - 25 30 90 - R-4 - 85 90 20 120 - R-5 - - 120 50 100 30 Chart 1.4 Stringless Bean Bend Degree to the Right (�1�) Degrees to the right (�) March 11 March 12 March 15 March 16 March 17 March 18 M-1 - - - - - - M-2 5 25 - 5 108 98 M-3 - - - 15 105 -10 M-4 - 0 - 26 20 30 M-5 - - - 85 -26 -40 T-1 - - - 6 82 - T-2 - - - 10 112 - T-3 - - - 19 106 - T-4 - - - - - - T-5 - - - 9 115 - K-1 - - 60 100 140 140 K-2 - - 60 40 120 60 K-3 - - 60 130 120 50 K-4 - - 50 50 70 60 K-5 - - 70 100 60 70 J-1 - - 60 24 17 100 J-2 - - - - 85 80 J-3 - 58 20 15 7 0 J-4 - - 15 55 90 90 ...read more.

Conclusion

The data then is inconclusive and no conclusion can be drawn. Aspect 2/3: Evaluate the Procedure/Improving Experimental Design: The experiment did not allow for the collection of sufficient data. Many factors were at play in making this lab inconclusive. First off, the amount of data collected was staggering, it makes processing the data harder and much of it was unnecessary. Instead of 8 groups of data, 3 groups should be used, each with 5 trials. This would make it a total of fifteen trials for each bean, more than enough to give results. Secondly, each group measured their beans differently and on different days, the quantitative data collected is filled with holes and gives incoherent results. All the bean measurements should be made by one person and the method of measurement should be uniform. Thirdly, most kidney beans did not show any signs of growth and only a few sprouted. This gave no results while being a waste of time and energy. Kidney beans should be omitted from the experiment and replaced with soy beans; soy beans grow faster and do not take long to germinate. This would give conclusive results to plant tropism, unlike the kidney beans. Lastly, the presence of fluorescent lighting in the experiment room may have influenced the beanstalk's growth as there are now two light sources in the environment. The extra light source could have changed the direction of bean growth towards it instead of the intended light source (the sunlight) and thus directly impacted the success of this experiment. Place beans in a room with only one light source, sunlight to the right of the plants, this could make the results more coherent. With these changes in place, the lab would be better and give better results. ...read more.

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