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Plants | Goals

General Unit Information

Figure 1: Plants Options for Calculating Dry Mass

The Plants unit builds on student learning about organic and inorganic materials in the Systems and Scale unit as well as the processes learned in the Animals Unit, including how all systems exist at multiple scales and the transformation of materials and energy during chemical change. In the Plants Unit students learn how the process of photosynthesis converts light energy from the sun into chemical energy stored in glucose, the process of cellular respiration transforms organic materials to inorganic materials and chemical energy to energy for function and movement of organisms, and the process of biosynthesis transforms food molecules into the biomass of an organism during growth.

Unit Goals

The tables below show goals for this unit in two forms. Table 1 shows unit learning objectives aligned with inquiry and application practices. Table 1 also contrasts the goal performance with performances of students at lower learning progression levels.

This table is followed by a list of Next Generation Science Standards (NGSS) addressed by this unit.

Type of Objective

Learning Objective

Challenges for Level 2 Students

Challenges for Level 3 Students

Inquiry: Measurement

3. Planning and carrying out investigations

4. Analyzing and interpreting data

5. Using mathematics and computational thinking

8. Obtaining, evaluating, and communicating information

Measure changes in dry mass of plants and soil.

Detect changes in carbon dioxide concentration caused by plants in the light and in the dark.

Level 2 students may have trouble reading digital balances and attaching meaning to measurements in small fractions of grams.

Level 2 students will not think of air as a mixture of different gases, so while they can understand that BTB detects carbon dioxide, they will not think of carbon dioxide as one of the mix of gases in the air.

Level 3 students may have trouble accounting for tare mass and interpreting small fluctuations in readings on digital balances.  They will have difficulty identifying threats to accuracy and precision in measurement.

Inquiry: Arguments from evidence

2. Developing and using models

3. Planning and carrying out investigations

4. Analyzing and interpreting data

5. Using mathematics and computational thinking

6. Constructing explanations

7. Engaging in argument from evidence

8. Obtaining, evaluating, and communicating information

Construct arguments that use evidence about mass gain in plants, and carbon dioxide concentration in air to defend claims about movements of atoms and chemical changes during plant growth and functioning.

Level 2 students will not interpret changes in mass as evidence of movements of atoms, believing instead that plants gain mass simply by “getting bigger” or by cell division (without cells needing new matter to divide).  They will also believe that a plant’s mass can be created from “food and energy” without accounting for the idea that the carbon that builds the glucose molecules must have come from somewhere (the air).

Level 3 students will see the relevance of evidence to claims, but they will not systematically consider alternate hypotheses or show how evidence supports or refutes specific claims.

Inquiry: Collective validation

3. Planning and carrying out investigations

4. Analyzing and interpreting data

5. Using mathematics and computational thinking

7. Engaging in argument from evidence

8. Obtaining, evaluating, and communicating information

Find patterns in data collected by multiple groups about changes in mass or gas exchange in plants.

Level 2 students may focus primarily on their own results rather than seeing the value of multiple measurements.

Level 3 students will understand that multiple measurements are valuable, but they will have few strategies for finding patterns across multiple trials.

Application: Matter Movement question

2. Developing and using models

6. Constructing explanations

7. Engaging in argument from evidence

8. Obtaining, evaluating, and communicating information

Describe plant systems and processes in a hierarchy of scales, including atomic-molecular, macroscopic, and large scale.

Draw and explain movements of materials in a growing plant, including:

·       carbon dioxide, oxygen, water, and minerals entering a plant

·       Sugar, water, and minerals moving within a plant, and

·       carbon dioxide, oxygen, and water exiting the plant.

Level 2 students will explain plant growth and functioning as actions of the plant (e.g., the plant makes itself bigger).  They will not interpret mass gain in the plant as evidence that atoms are moving.

Level 3 students will describe a general movement of materials in the plant, but may not confuse the roles of matter and energy in plant growth.

Application: Matter Change question

2. Developing and using models

6. Constructing explanations

7. Engaging in argument from evidence

8. Obtaining, evaluating, and communicating information

Describe molecules of key materials in plant processes, including atmospheric gases, soil minerals, water, and organic materials.

Explain how atoms are rearranged into new molecules in photosynthesis, biosynthesis, and cellular respiration in plants. 

Level 2 students will explain what happens as an action of the plant (the plant grows and gets bigger) rather than as a chemical change in which atoms and mass are conserved.  They will recognize that plants need food and energy to grow, but they will not try to trace those materials through the chemical change process.

Level 3 students will recognize that a chemical change is taking place, but they will not be able to successfully trace all the materials through the plant.  They may not exhibit a sense of necessity in tracing carbon from the air to small organic molecules to large organic molecules to plant biomass and back to the air.

Application: Energy Change question

2. Developing and using models

6. Constructing explanations

7. Engaging in argument from evidence

8. Obtaining, evaluating, and communicating information

Identify forms of energy at different stages of plant growth and life processes.

Explain transformation and conservation of energy during photosynthesis, biosynthesis, and cellular respiration in plants.

Level 2 students will recognize that the sun is a form of energy, but they will not be committed to the idea that this energy is transformed into chemical energy that is stored in the bonds of the organic molecules in the plant.

Level 3 students are likely to identify glucose as an energy source for the plant, but they may not distinguish between matter and energy within the molecule, conflating the role that matter plays in plan growth with the role of energy.