Tree Straws Activity
Grade Level: 4-8
MS-LS1: From Molecules to Organisms: Structures and Processes
LS1.A: Structure and Function
LS1.B: Growth and Development of Organisms
LS1.C: Organization for Matter and Energy Flow in Organisms
PS3.D: Energy in Chemical Processes and Everyday Life
MS-LS2: Ecosystems: Interactions, Energy, and Dynamics
LS2.A: Interdependent Relationships in Ecosystems
LS2.B: Cycle of Matter and Energy Transfer in Ecosystems
Content Area: science
Recommended Length/Duration: 30-45 minutes
Goals: Based on grade level, students learn about the properties of different types of wood, about xylem and phloem, living cells vs dead cells in trees, the growth of hardwood and relative strengths, tree transpiration/translocation (root water uptake, pressure differentials…)
(MS-LS-1: Conduct and investigation to provide evidence that living things are made of cells; either one cell or many different numbers and types of cells.;MS-LS1-6: Construct a scientific explanation based on evidence for the role of photosynthesis in the cycling of matter and flow of energy into and out of organisms. MS-LS2-3: Develop a model to describe the cycling of matter and flow of energy among living and non-living parts of an ecosystem.)
- Begin by describing structure of a tree. What does structural wood (“the trunk”) do in for a tree? What is wood made out of (mostly dead xylem, ect)? Students can draw a tree and then label the parts, leading to discussion of what each part does (roots, trunk, leaves)
- Have students examine a wood column with a magnifying glass. What do they observe? Why does the trunk consist of many tiny straws? Xylem, phloem à trees move things up and down their trunks…
- Resource flow within the tree. Use a drawn diagram to represent movement of water, sap, nutrients (energy) throughout a tree and connected to the entire ecosystem. Cycle: atmosphere, soil, roots, trunk, leaves, atmosphere.
- Conduct experiment with the wood columns, observe how far up the wood liquid will travel. What is pushing/pulling the liquid? (this is a big discussion and differs in the case of the experiment from the case of a living tree, probably. Discuss possibilities like surface tension, pressure differences…) Why do the different types of wood transport water differently?
- Have the students attempt to recreate the resource cycle of a tree using words, labeled diagrams, and sketches of their wood observations.
- Return to Idea that different trees have different wood which makes them good for different things
Have students write observations about the properties of each wood column. Which columns moved water the farthest? Why? Which had xylem/phloem large enough to suck water through? What determines the size of the xylem/phloem? Attempt to assess understanding of the movement of resources through a tree/ecosystem by asking students to represent these ideas in a drawn diagram.
- red oak column of wood, cut vertically from tree
- white oak column of wood
- water or distilled alcohol
- magnifying glasses/microscopes
- if you have enough pieces of wood, give each student a piece of each type of wood. Have them try to draw up the water through the wood by sucking on it like a straw.
- get a variety of other types of wood columns to see what happens
- Students could also examine a leaf with magnifying/microscope to try to observe stomata à discussion of transpiration of water vapor from tree into atmosphere.