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Where does a tree's mass come from?

4 hypotheses where plant's mass comes from

Students analyze evidence to evaluate four hypotheses about where a tree’s mass comes from.

Students engage in scientific practices as they learn that trees consist mainly of water and organic molecules and most of the mass of the organic molecules consists of carbon and oxygen atoms that came from carbon dioxide molecules in the air.

For example, students analyze Helmont’s classic experiment and evaluate whether his interpretation was supported by his evidence.

The Student Handout is available in the first two attached files. The Teacher Notes, available in the last two attached files, provide instructional suggestions and background information and explain how this activity is aligned with the Next Generation Science Standards.

Attachment	Size
PlantMassFromSHO.docx	2.11 MB
PlantMassFromSHO.pdf	607.23 KB
PlantMassFromTN.docx	1.89 MB
PlantMassFromTN.pdf	758.69 KB

Comments

How long did this take

Submitted by Golda (guest) on Tue, 11/07/2023 - 10:51pm.

How long did this take people's classes?

Guesstimate of how long it takes

Submitted by iwaldron on Thu, 11/09/2023 - 6:26pm.

How long this activity will take depends on your students, their prior learning, and whether you give them time to work through the questions (in pairs) before a whole class discussion of the questions (see Teacher Notes). I would guess that this activity will take approximately 30-50 minutes.

Ingrid

2022 revision

Submitted by iwaldron on Mon, 09/12/2022 - 5:49am.

I have improved the logical flow of the Student Handout, clarified many of the questions, and added two new figures.
Ingrid

September 2017 revision

Submitted by iwaldron on Wed, 09/27/2017 - 4:39am.

The Student Handout has been revised to incorporate more analysis of experimental evidence and to improve logical flow and clarity.

Ingrid

2017 revision

Submitted by iwaldron on Mon, 03/06/2017 - 10:41am.

Additional figures and substantially revised questions in the Student Handout will help students better understand the reasoning and the important concepts (including the relevant NGSS Disciplinary Core Ideas and Crosscutting Concepts).

2016 revision

Submitted by iwaldron on Wed, 08/03/2016 - 2:59pm.

These revisions have improved clarity and accuracy.

2014 revision

Submitted by iwaldron on Thu, 06/05/2014 - 10:15am.

The questions in the Student Handout have been clarified so students can more readily think through the logical flow of the argument. The revised Teacher Notes have improved suggestions for teaching this activity and enhanced background information and also clarify the alignment of this activity with Next Generation Science Standards.

Biology

Submitted by Logan mannix (guest) on Wed, 12/14/2011 - 8:49pm.

Thanks for the help

Revised Version of Student Handout

Submitted by iwaldron on Tue, 03/08/2011 - 7:08am.

This revised student handout provides a more complete set of questions to help students evaluate each of the hypotheses concerning where a plant's organic mass comes from. In addition, the wording and logic of the questions has been clarified.