Seed Dispersal Investigation
In this set of second grade investigations, students seek to understand how plants around their school might end up growing in new places next year. They conduct tests to understand how seeds can travel by wind, water, and sticking to people and animals. They consider how to test indoors processes that normally happen outdoors (How much wind should we use? From what height should we drop the seed?). They make sense of how their tests help them understand what happens outside (if the seed floats but there isn’t a river near the school, how likely is it to get to a new place by water?). Finally, they look across the results of their investigations to develop an explanation of how their focal seed could travel and grow in a new place.
Context
Before the investigations, students learn about plant growth and needs as they investigate corn, using lessons based on the NGSS Storylines unit, "Why is our corn changing?". Then, they collect seeds near their school and investigate how those seeds could travel to new places and make new plants in those places. Students explore form/function relationships and learn that plants produce seeds to make more of their kind. They consider why it's important for seeds to travel and explore the parts and ecological relations (e.g. mutual relationships with animals) that support travel.
Authors: This investigation was developed with support from Lauren Woldemarium, Diana Garity, Nora Studley, Pat O’Brien, and Griselda George (Somerville Public Schools)
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NGSS Standards
2-LS4-1. Use texts, media, or local environments to observe and compare (a) different kinds of living things in an area, and (b) differences in the kinds of living things living in different types of areas.
2-LS5-2. Develop a simple model that mimics the function of an animal in dispersing seeds or pollinating plants.
Forms of Uncertainty
Among other uncertainties, students in these lessons are supported to engage with:
How to represent the phenomenon: Students consider how to represent seed travel inside; for example – how can they use a fan to be like the wind (speed, where to aim the fan, how high up the seeds should be and whether on their own/on branches/in pods)
How to develop an informative comparison: Students discuss if tape would be a good material to use to test if seeds can travel by sticking. This discussion supports children to explore the difference between "figuring something out" and "forcing something to happen".
How to organize and represent data: Students decide how to keep track of the distance that each seed travels during the wind investigation.
How to generalize: Children argue that their results from using a fan inside to test the flight of the maple seed don’t provide enough information about what would happen outside, because of differences in height and wind speed.
Explore the full Uncertainty Overview for this investigation to learn more about these and the other forms of uncertainty that students engage with in this investigation.
What Happens in This Investigation?
Engaging with the Phenomenon
Students begin to explore seeds outside, noticing some are still on their parent plant and some are in different places. They read books about how seeds travel and why seeds may have to travel away from the parent plant. Each student chooses one focal seed from a set that lead to interesting contrasts (e.g. milkweed, Queen Anne's Lace, maple seeds, berries). They make and share predictions about how their seed could travel.
Explore related forms of uncertainty, instructional materials, and tools.
Seed Dispersal Investigations Overview
Lesson 1: Where can we find seeds?
Lesson 2: Why and how do seeds travel?
Lesson 3: Making predictions about our seeds
Investigating and making claims about how focal seeds travel
Through a set of three investigations, students explore different types of seed dispersal. They consider what claims they can make about how their seeds travel and what about the seed or plant might matter for how it travels.
Water Investigation
Students watch a video of a coconut traveling by floating on ocean water. They consider if their seeds are good floaters. The teacher demonstrates how to test this using a tub of water. Students test, describe what happens, and make a claim. The class discusses claims and engages in sensemaking about whether seeds could travel by water near their school.
Wind Investigation
Students watch a video showing seeds traveling by wind and make sense of the features that make seeds good wind travelers. The teacher asks how they could use a fan to test if any of their seeds can travel by wind. Students discuss how to conduct this test, making key decisions like how high to place the fan, where to hold the seed, and how to keep track of how far the seeds travel. They test, observe, and make and discuss their claims.
Explore related forms of uncertainty, instructional materials, and tools.
How to represent the phenomenon
Lesson Plan 4: Water Investigation
Lesson Plan 5: Wind Investigation
Lesson Plan 6: Sticking investigation
Sticking Investigation
Students revisit a book and watch a video to think about how seeds stick to animals and people. The teacher presents several types of fabric and asks which of these fabrics would be best for representing clothing and animals. Students work in groups to decide how they will use the fabric to test if their seeds travel by sticking, investigate, and then make and discuss claims.
Claims, evidence, and explanations children develop in conversations after each investigation.
Developing Explanations
Students work in groups to look across their evidence sheets and make a claim about how their seed travels best. Then, they explain how their plant could get to a new place in or outside the schoolyard. They create posters to share their ideas, then discuss what they have learned about seeds and about doing science.
Explore related forms of uncertainty, instructional materials, and tools.
Lesson Plan 7: Explaining How Our Seeds Travel
The grass seed group shows how their seed could travel by sticking, and maybe by wind or water.