Lesson 5: Testing Plant Growth

Whole-Class Lesson:

1. Students should start the lesson by getting a device and going to this link: https://todaysmeet.com/Castings
2. Students should carefully examine the samples that are on display. They may use pencils to poke at the samples and magnifying glasses to see things up close.
3. As students observe things, they should post them on our Today's Meet page that is projected in the classroom.
4. Students should record properties of the samples (size, shape, color, etc.) on the Today's Meet.
5. Once everyone has had some time to observe, discuss the observations together as a whole group.
6. Are these samples organic or inorganic? How can you tell?

BIG IDEA 5:
Nutrients in the soil (or water) are used by plants and other organisms.

Vocabulary:

• Properties
• Organic
• Inorganic
• Castings
• Humus
• Top Soil
• Perlite
  
• Control Variables
  
• Independent Variable
  
• Dependent Variable
  

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Whole-Class Lesson:

1. Discuss the ingredients in the potting soil bag. Explain humus & watch this BrainPOP video: https://www.brainpop.com/science/earthsystem/soil/
2. Explain humus: (1) helps keep soil crumbly so it's easier for plants to grow, (2) absorbs water easily so that it's available for plants, (3) contains organic matter.
3. Explain the differences between top soil, sub soil, and bed rock.
4. Explain perlite: (1) a form of volcanic rock, (2) inorganic, (3) sometimes used to allow air to flow through soil and make soil higher in weight, (4) used to make concrete, plaster, and insulation.
5. Discuss sand and any other inorganic materials we're using today.
6. Which of these materials do you think plants will grow better in?
7. Why do you think one material is better than another for plant growth?

http://image.slidesharecdn.com/soil1-150122011758-conversion-gate02/95/soil1-7-638.jpg?cb=1421889509

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A seed that has germinated.

Blog Post:

Today, we're going to set up an experiment to compare plants grown in different soil types (this may be done differently than the following directions). We are going to try to grow some plants in organic material (potting soil with worm castings) and some in inorganic material (perlite).

Create the following chart in a blog entry. Type everything that we put on the board into the chart. You will eventually choose one item from each column to do an experiment on!

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Independent Variable

• Plant seeds in different kinds of soil (e.g. potting soil, perlite, sand, etc.)
  

Dependent Variables

• Measure the height of each plant at certain checkpoints.
  
• ________________________
  

Evidence

• We can record our data using measurements (in cm).
  
• ________________________
  

The back of leaves that are beginning to develop in a newly germinated seed.

The front of leaves that are beginning to develop in a newly germinated seed.

What are some things we can collect data on while growing seeds in different types of soil? (Put answers into the 2nd column in your blog post.) (Don't look at the answers after the "Read More" break, just make sure you talk about all of them):

• How many days it takes each seed to sprout.
• The height of each plant at certain checkpoints.
• Leaf color.
• Root structure.
• Number and size of leaves.
• Whether or not a seedling survives after a certain number of days.
• The date a seedling dies.
  

How can we measure or evaluate our observations? For example, for some of these we will need to measure the plants' heights. What about the others? What units should we use? (Put answers into the 3rd column.)

• Measure height of plants in centimeters and record them.
  
• Take photographs on specific checkpoint days and catalog them.
  
• Count numbers and record them.
  
• Record dates.
  

One version (we may do it differently): Choose one bullet from each column on the chart above.  This will be YOUR experiment.  (Others may have the same experiment as you do.)

Everyone in class needs to get the materials to plant three seeds: one in potting soil, one in perlite, and one in sand.  We need to plant each seed according to the directions to the right and record our predictions in this blog post.

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Reflection/Synthesis:
Answer the following questions in your blog post. Remember to have at least one follow-up sentence for each question, when possible.

1. Name your Control Variables (What will stay the same for each of the three cups)?
2. Name the Independent Variable (What is it that is different for each of the three cups)?
3. Name your Dependent Variable (What is it that you are testing & recording data on?)
4. What data are you collecting to serve as Evidence to show how plants grow in organic material versus inorganic planting material?
5. Why is everyone starting with the same three cups? Why do we need to test so many plants?
6. What sprouts first in a seed: the stem or the root?
   
7. How do you know? How do the pictures below help explain your answer for #6?
   
8. Why do you think it goes in that order?
   

Answers:

1. .
2. .
3. .
4. .
5. .
6. .
7. .
   
8. .
   

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When the experiment is over:

Be sure to record all of your evidence and data on this blog post as you conduct the experiment (i.e. photographs, Data Chart, etc.).

Once data collection is done, answer the following questions:

Data Analysis Questions:

1. Where did your plants get ENERGY for growth?
2. Where did your plants get MATTER for growth?
3. Where did your plants get OTHER NUTRIENTS for growth?
4. Explain how each of your three cups were like individual ECOSYSTEMS. This is a good test to see if you understand what an ecosystem really is.
5. What are the individual components of each ecosystem?
6. What are some ways that the components of the ecosystem interacted with each other?
7. Describe ways that you could expand this experiment. What do you wonder about? What would you do differently if you could do another experiment that was similar?

Answers:

1. .
2. .
3. .
4. .
5. .
6. .
7. .

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When you finish your blog post (and do it well), check out this website.