Top: Life Cycle (Photo by Alpsdake via Wikimedia Commons)

Setting the Stage

Science has a classification system for organizing all living things, including plants. Botanists (scientists who study plants) must find a way to categorize the millions of different plant species that exist on Earth.

While all plants are made up of similar parts that are essential in maintaining their survival (e.g., roots, stems, leaves) these parts often look and behave differently. For example, one way botanists classify plants is by looking at how they take in water and nutrients. Another way botanists classify plants is by looking at how plants reproduce. For examples, plants in the grass family reproduce by sending out underground stems called rhizomes while other plants grow from seeds or spores.

In this inquiry, students will use their observation skills to compare & contrast seeds and bulbs as they learn various ways of starting new plants. As they explore the life cycles of plants grown from seeds and bulbs, students will begin to recognize the link between themselves and other living things and appreciate the benefits and responsibilities they have for the care of these organisms.

When preparing to work with plants students should understand the importance of never tasting any part of a plant and washing their hands after handling any part of a plant.

cut flowers in a vase

Cut flowers (Photo by Let's Talk Science)

This inquiry could begin from:

  • Questions and/or comments from students about a vase of flowers on a table in the classroom. Discuss using questions such as:
    • "What do we know about these flowers?" (e.g., they are living things, they are plants)
    • "What are some parts of the plants that you can see? What parts can't you see?"
    • "Where do plants like these come from?" (e.g., some students may have experience with planting bulbs or seeds to grow flowers)

  • Questions and/or comments from students about a collection of conifer cones brought in by a student. Discuss using questions such as:
    • "Where might you find cones like these?"
    • "What role do they play for conifer trees? (They are where we find the seeds.)
    • close up of spruce tree

      Spruce Tree (Photo by foto_mama via Pixabay)

    • "What do you notice about the scales of these cones? (They overlap.) "Why do you think they are designed this way?" (to protect the seeds inside)
    • "How do you think the conifer seeds get dispersed?" (e.g., when the cones fall from the trees; when an animal or the wind carries the cones to another place)

  • Watching a video such as From Seed to Flower (Nova) and reading a book such as From Seed to Plant. Discuss using questions such as:
  • cover of From Seed to Plant

    Front cover of From Seed to Plant by Gail Gibbons (Cover image via Open Library)

    • "How would you describe some of the steps a plant goes through when it is growing from a seed to a plant?"
    • "What are some of the parts of plants we saw in the video? What parts did we not see? Why are some parts easier to show in a video than others?"
    • "What role does each part of the plant play in its growth and development?" (e.g., the stamens make pollen; the petals attract pollinators to the plant; the roots carry water and nutrients to the rest of the plant)
    • "Does a seed need the same things to survive as a full-grown plant needs? What is the same and what is different about their needs?"

Materials and Preparation (Click to Open)

Materials:

  • a collection of seeds (e.g., sunflower seeds, pumpkin seeds, poppy seeds, sesame seeds, pinto beans, soy beans, tomato seeds, coffee beans, seeds from flowers, fruits and vegetables) (Note: when considering seeds for planting, think about fast-growing ones like nasturtium, morning glory, sunflower, tomato, beet or radish seeds, if available.)
  • bulbs (Note: most bulbs are poisonous if ingested. For safety, consider using edible bulbs like onions, green onions or leeks, or have the children wear disposable gloves when handling the bulbs.)
  • hand lenses
  • paper towels or other white material on which to place seeds for observing
  • samples of other ways in which plants get started: cuttings, grafts (optional)
  • small containers for planting (Note: some local woodworking/home and garden stores sell devices for making your own pots from newspaper, eliminating the need for plastic pots)
  • potting soil or peat pots (Note: If using soil, consider using sterilised compost for safety purposes, or have students wear disposable gloves when handling soil.)
  • spoons for scooping soil
  • disposable gloves (optional)
  • newspaper for covering tables while planting

Preparation:

  • Educators may wish to:
    • place samples of seeds in small snack bags ahead of time for easy distribution to students
    • place samples of flowering bulbs in snack bags for safe observation (optional)
    • pre-measure soil for planting (if using)

What To Do

Students develop and apply the skills of comparing & contrasting, observing and communicating as they explore the life cycles of familiar plants.

Students:

Pumpkin and Seeds (Photo by Gellinger via Pixabay)

  • Observe the collections of seeds with their eyes and then through a hand lens.
    • Educator facilitates discussions, encouraging students to observe and describe features of the seeds such as size, shape, colour, markings, etc.
  • Record what is observed and thoughts that arise from the discussions.
  • Observe examples of bulbs and compare and contrast them to the seeds.
    • Educator facilitates discussions, encouraging students to observe and describe features of the bulbs such as size, shape, colour, markings, etc.
  • Select a seed or a bulb to grow.
    • Educators ask students to predict what might grow from their seed or bulb - e.g., will it be short or tall, have a flower or no flower, produce fruit, etc. Students may also notice that some bulbs have roots already showing, which can spark a discussion about things that grow from seeds and where their roots are.
  • Determine how they will record the changes their plant goes through in its life cycle, from seed/bulb to a full-grown plant, and the kind of care they will need to provide for the seeds to germinate and then to continue to grow.
    • Educator facilitates discussions, discussing how students can keep track of the time it takes for the different stages of plants to appear, use of digital tools to record, how to describe what they see happening at each stage, etc.
  • Plant their seeds/bulbs.
  • Record changes over time in the life cycle of their plant.
  • Compare and contrast stages of the life cycle of their plant with that of plants grown by others.
    • Educator facilitates discussion, asking students to compare the time it took for their seeds to germinate, the speed at which their plant grew leaves, what differences were noted between plants grown from seeds and plants grown from bulbs, etc.

Assessment

Observe and document, using anecdotal comments, photos and/or video recordings, students' ability to:

  • Observe - students observe different kinds of seeds and bulbs with their eyes and through a hand lens
  • Compare & Contrast - students compare & contrast different kinds of seeds and bulbs including observations made with a hand lens
  • Communicate - students discuss and record observation
  • Communicate - students use a variety of methods (e.g.,drawings, photos, labels) to record the growth and change in their seeds from germination to plant using appropriate vocabulary

Co-constructing Learning

Students:
Saying, Doing, Representing

Educator Interactions:
Responding, Challenging

Students observe seeds and bulbs with their eyes and through a hand lens.

  • "What are some things you observed about the seeds?"
  • "What did you observe about the bulbs"
  • "What did you observe through the hand lens that you could not see with just your eyes?"

Students compare and contrast seeds and bulbs, including observations made with a hand lens.

  • "How are the seeds the same? How are they different?"
  • "How are the bulbs the same? How are they different?"
  • "How are the seeds and bulbs the same? How are they different?"
  • "What similarities and differences were you able to see with the hand lens that you could not see with just your eyes?"

Students discuss and record observations.

  • "Do you think that the size of the seed/bulb will affect the size of the plant that grows from it? Why do you think that?"
  • "How can you tell if a seed is right side up for planting? Why do you think that?"
  • "How can you tell if a bulb is right side up for planting? Why do you think that?"

Students record the growth and change in their seeds from germination to plant.

  • "What did you observe about the time it took for the seeds to germinate? Did the size of the seed have an impact on germination? Why do you think that?"
  • "What did you observe about the time it took to see growth from the bulbs? Did the size of the bulb have an impact on this? Why do you think that?"
  • "Did the way that you care for the plants change after they germinated? Why/why not?"
  • "How did the growth and change look the same amongst the different seeds we planted? What differences did you notice?"

Cross-Curricular Connections

Literacy

  • Use words and phrases that will help convey meaning as specifically as possible (e.g., use comparative adjectives such as smaller, smallest; use appropriate scientific vocabulary such as germinate, stem, leaf, root, flower, stamen, pistil)
  • Use a variety of forms (e.g., oral, written, graphic, multimedia) to communicate (e.g., create drawings or take photos for a science journal to track plant growth)

Mathematical Thinking

  • Measure using standard units (e.g., measure time from planting to germination; measure growth of a plant over time)

Visual Arts

  • Create two- and three-dimensional works of art that express ideas inspired by observations of nature (e.g., create illustrations that show observations made about seeds and bulbs, seed germination, plant growth and change)

Extending the Learning

If your students are interested in learning more, the following may provoke their curiosity:

  • Some students may be interested in exploring other ways of starting plants. Provide examples and/or pictures of cuttings and grafts and discuss using questions such as:
    • "What do you predict is meant when we say we can grow new plants from cuttings?" (A cutting is a piece of the stem of a plant that is cut from the parent plant and repotted.)
    • "What would be some of the advantages of growing a plant from a cutting?"
    • "What do you predict is meant when we say we can grow new plants by grafting?"
    • "What would be some of the advantages of growing new plants by grafting?" (Grafting allows growers to get exact duplicates of a plant that has been very successful - one that has produced perfect juicy peaches or gorgeous roses, for example. Also, grafted plants grow faster than plants grown from seeds so growers get the product much sooner than they might otherwise.)
    • "What types of plants do you think would lend themselves to being grown from cuttings or from grafting?"

    Taking a cutting (Photo by Hydrob via Wikimedia Commons)

    Grafting plants (Photo by Pearson Scott Foresman via Wikimedia Commons)

  • Students may be unaware that strawberries grow in fields or that carrots grow in the ground. Educators may wish to set up provocations that provide opportunities to explore the "food from farm to fork" concept. A farm visit would be ideal, but where that is not possible books and videos such as the ones suggested below provide a starting point for further explorations.

Videos

Where do fruit and vegetables come from?
https://www.youtube.com/watch?v=CdPRZ3wjCxA&t=36s
food that grows on trees, on vines, and in the ground

Where does food come from?
https://www.youtube.com/watch?v=7vH2yxjQ-uk
from 1:05 - end - focuses on tomatoes from farms, looks inside the tomatoes at the seeds, and shows tomato plant growth

Where does rice come from?
https://www.youtube.com/watch?v=kxAEiHCErSA
good overview of how rice is growns

How is bread made
https://www.youtube.com/watch?v=6cD-jqABVYc
overview from field to grocery store

Books

Cover of Where Does Food Come From? by Shelley Rotner and Gary Goss (Photo via Open Library)

  • Where Does Food Come From? by Shelley Rotner and Gary Goss
    • a book about making connections (e.g., cocoa beans are seeds that grow on cocoa trees, chocolate is produced by grinding and cooking cocoa beans, and hot chocolate is made from chocolate)
    • includes an interesting fact on each spread ("a lemon is a type of berry")

  • Where Does Fruit Come From?, Where Do Vegetables Come From?, Where Do Grains Come From? all by Linda Staniford
    • books look at how fruits, vegetables and grains are planted, grown and harvested before they get to our tables