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Pickleweed Seed Germination Experiment

Life Skills:

  • Thinking & Reasoning
  • Communication

Time Frame:
1 class period that runs 45 minutes.

Group Size:
Small Groups


 

Summary:
This lesson is all about the procedures of how to extract seeds from pickleweed plants and to germinate those seeds by using the different variables of leaching and non-leaching.

Materials:
Several handfuls of dried Pickleweed plants per group; 1 Large paper bag per group; 10 Pickleweed seeds per group; 1 school paper towel per students; Several flat dishes per group; 1 cookie sheet or flat shallow box per group; Dissecting microscope or large hand magnifying glass per group; One Sharpie per group; Masking tape; 1 sandwich size sip-lock baggies per group; 2 nylon knee high or cut-off the legs of a pair of panty hose (8 inches in length); 2 sizes of screens, kitchen strainers will work; Science notebook

Background For Teachers:
Pre-Experiment Preparation: Gather Pickleweed Plants on the Great Salt Lake Field Trip; Dry Plants for a couple of weeks prior to the experiment; Students need to learn to identify the seeds before beginning the sorting process; Before doing this experiment students should have already learned about the unusual qualities of the Great Salt Lake environment and how plants and animals have undergone unique adaptations in order to survive in such a harsh environment; Students will have made a field trip to the GSL to study the different vegetation zones around the playas and to collect Pickleweed plants for the experiment.

Instructional Procedures:
Since the Pickleweed seeds are very small it would be a good idea to draw a picture of what the seeds look like along with a brief description to prepare the students for the sorting activity. Divide Pickleweed plants into the paper bags and giving one bag to each group Fold the end of the bag under several times or tape it shut Place the bags on the floor and have students take turns walking on the bag as if mashing grapes (be careful not to break the bag) After 4 or 5 minutes open the bag to see if the plants have broken down into small pieces Place a handful of Pickleweed pieces on the coarsest screen and over a tray gently shake it until the small seeds fall through and all that remains is the larger pieces of plant Gently run a hand over the material remaining in the screen to see if any more seeds will fall through Empty the screen and put the left over plant material in a dish and save incase it needs to be resorted Repeat this process until all plant pieces have been sifted once Remove material from tray and place in a dish Using the same sifting technique run the sifted material through the smaller screen until all the plant pieces have been sorted a second time Winnow the seeds that have been sifted a second time by pouring the seeds into a shallow dish and gently blowing over them. Small pieces of plant mater will fly out of the bowl, which separates the seeds from the plant even further Sort seeds by using the dissecting scope or a magnifying hand lens pour out a small amount of sifted material and using tweezers, gently pick out the seeds from the left over plant placing them on the paper towel envelop Each student will place 10 seeds onto the center of their own paper towel envelope Write on the thick side of the envelope where all of the ends meet. Each envelope should contain the following information, with a pencil write: name, type and number of seeds, date sorted, what variable used (ie. leached-light or leached-no light) How to make the paper towel envelopes: 1) use school paper towels because they are tough and won't fall apart like most paper towels 2) unfold the paper towel so that it is flat 3) fold the bottom of the towel 1/3 of the way up 4) fold the right side 1/3 of the way over 5) fold the left side 1/3 of the way over 6) fold the top 1/3 of the way down Setting the Experiment Variables: Unleached-light: a) the unleached seed packets need to wet b) place in a zip-lock baggie c) spread seed packets out in the baggie with the seed side facing upward d) place baggie in direct sunlight e) make sure that the baggie is sealed to keep in the moisture Leaching: 1) place all the packets of seeds labeled leached into a couple of nylon stockings 2) tie a loose loop in the end of the stocking and hang it over the end of the facet (you can use rubber bands or twist ties to hold the stockings in place) 3) turn the facet on and let it drip slowly over the seeds for 24 hours 4) after leaching 24 hours remove the seed packets from the stocking and place them in a plastic baggie Leached-light: a) place leached seed packets labeled light into a zip-lock baggie b) spread seed packets out in the baggie with the seed side facing upward and the writing side facing downward c) place baggie in direct sunlight d) make sure baggie is sealed to keep in the moisture Observations: On a daily basis the students should check the progress of the seeds noting the changes and comparing them to the previous observations and record their observations in their science notebooks (note that it takes several days for the seeds to show signs of germination and nearly a week before they should be counted) After seeds have had an opportunity to germinate, then the germinated seeds should be counted and results recorded Make a graph using the seed germination results to show the difference between the different variables Make conclusions about the experiment data and compare the results with the hypothesis in the beginning of the experiment Science Notebooks should contain the following headings: student's name, title of experiment, purpose statement of the experiment, hypothesis, materials used, methods, observations & reflections with dates, results, conclusions

Extensions:
There are many different activities involved in these lessons and children who are unable to do some of the tasks such as sort small seeds should be given tasks that fit their needs. When using this activity for younger grades cut the amount of seeds sorted down and also decrease the number of variable factors used in the experiment.

Assessment Plan:
Science journals, simple rubric to evaluate the journals, simple rubric to evaluate student participation, use informal questioning as a strategy to obtain information about the students understanding of the experiment, have students present their results to the rest of the class

Bibliography:
Harrison, Dr. Ty Great Salt Lake Playa Project (, )

Author:
KAREN LYNNE

Created Date :
Dec 09 2000 15:15 PM

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