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Problem of the Week

Seed Germination

Week 1

I designed problem of the weeks to give students an opportunity every week to practice their skills of scientific research. I try to choose simple experiments where the outcomes are tricky or not what the students expected. (This isn’t always possible if I want them to learn a specific concept.)

Problems of the Weeks develop and test students skills such as:

• Making predictions before doing the experiment
• Following step by step directions
• Thinking creatively for alternative solutions
• Forming hypotheses of why something occurs
• Testing hypotheses
• Creating and following their own experimental procedures
• Observing carefully
• Writing detailed observations
• Writing conclusions that incorporate results and make sense from what was observed.

I get my ideas for POWs from lots of different science sources. I rewrite simple experiments into a format my students learn to get used to. I expect my students to write up their own POWs in a particular format and always show them excellent examples of their own peers. When creating POWs I follow some simple guidelines:

• Can the students find the materials in their homes or easily acquire them?
• Is there an item I can easily provide them?
• Is the phenomena interesting?
• Are the procedures fairly simple and hard to screw up?
• Will not following the procedures clearly not produce the desired outcome?
• Will the experiment create some family interest and family talk?

I encourage my students to TALK to their families, get ideas, and let their families know that the seeds on the sponge in the closet should not be thrown out!

The following POW Flow chart is what I hand out to my students and review with them at the beginning of and throughout the school year. I expect to find this in their take-home notebook when I do notebook checks.

Problem of the Week

A Two-week POW

Due Date__________ Lesson 5

Materials: grass seed from your teacher, 1 sponge, scissors, 2 saucers or foam trays(packaging) from meat or fruits, water, measuring cup, window or light source, dark area such as closet or box

Prediction: Will grass seeds germinate without light? Will seeds germinate at the same rate without light as with light? Will plants grow the same as in light and in the absence of light? What are some differences that might occur?

Procedure:

1. Cut the sponge in half.

2. Place each half on its own saucer or small tray.

3. Sprinkle grass seeds over each sponge.

4.Add ½ cup water to each saucer ( the water should be absorbed into the sponge).

5. Place one saucer with sponge and seeds by a window or constant light source.

6.Put the other saucer in a dark closet or box that can be sealed (such as a shoe box).

7. Design a data table that you can write your observations in each day. It should have a categories for time checked, day of experiment, added water, and observations.

8. Check your saucers each day for 2 weeks. If the saucer or sponge is getting dry you need to add water. Keep track of how much water you add to each saucer. (Which sponge do you think will need more water more frequently? Why?) Check your seeds daily and take detailed observation notes.

Write down your predictions and reasoning before you begin.

Results and Observations: After 2 weeks of observations, what did you discover? Draw diagrams, color pictures, rewrite your observations so they are clearly understood.

Hypothesis: Think about the reasons why you got the differences you did between the plants in light and those in dark. Come up with a hypothesis that explains the phenomena you saw.

Based on what you learned in class about chlorophyll, design an experiment to test your hypothesis. How would you prove that your thinking is correct?

Just write what your test would be. Don’t do it. Remember: Step by step procedures!

Conclusion: Do you think you did the experiment correctly? What mistakes did you make? Why was the grass kept in the dark different?( Explain it in terms of what you learned about the process of photosynthesis.) What kind of growth occurred in the light and in the dark? What accounts for these differences? What did you learn from running this experiment? What questions do you have after completing the experiment? What curiosities?

Put the 2 sponges with growing seeds in plastic baggies or wrapped in plastic wrap. Make sure your name is on them. Hand them in with your POW write up.

Problem of the Week

Photosynthesis: Form and Function

The exchange of water and gases in plants

Your assignment as a team is to take all that you have learned from your individual readings, and design a poster that should be part flow chart, part diagrams. The objective of the poster is to describe the parts of the plants that are involved in gas exchange and fluid movement.

• Using labeled diagrams, show the parts and explain how they function. There should be a flow of information or some type of cycle. Arrows should show the correct direction of movement of the liquids and gases.
• Information about photosynthesis, osmosis, cell types and structures, transpiration stream, respiration, and plant structures involved are mandatory. Gases and fluids must be correctly named and labeled.
• Look at the Rubric. Pay attention to it. It can guide you.

PLAN FIRST BY TALKING, THEN PLAN ON SCRATCH PAPER. You will only be provided with one large piece of paper. MAKE LISTS OF WHAT YOU KNOW YOU NEED TO INCLUDE. BRAINSTORM!

http://biology.arizona.edu/sciconn
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