Lesson Plan

Photons In The Radiative Zone: Which Way Is Out?

Subject Area

Science

Grade(s)

9, 10, 11, 12

Overview

In this activity, students try to work their way out of a circular maze, thereby modeling the movement of a photon as it travels through the radiative zone of the sun. Classroom discussion after they complete the activity is focused on the Standard Solar Model and its importance in further scientific studies of the sun.

This lesson was created as part of the 2016 NASA STEM Standards of Practice Project, a collaboration between the Alabama State Department of Education and NASA Marshall Space Flight Center.

Content Standards

Science (2015) Grade(s): 09-12 - Earth and Space Science

SC15.ESS.1
Develop and use models to illustrate the lifespan of the sun, including energy released during nuclear fusion that eventually reaches Earth through radiation.

Unpacked Content

Vocabulary

mass
temperature
nuclear fusion
radiation
convection
hydrostatic equilibrium
flux
random walk
red giant
planetary nebula
white dwarf

Knowledge

Students know:

The sun is a star The sun is changing and will burn out eventually.
Nuclear fusion processes in the center of the sun release energy that reaches Earth as radiation. Hydrogen is the sun's fuel.
Helium and energy are products of fusion processes in the sun.

Skills

Students are able to:

Develop models to predict and show relationships among variables between systems and their components in the natural and designed world(s).

Understanding

Students understand that:

The scale of the energy released by the fusion process is much larger than the scale of the energy released by chemical processes.

Scientific and Engineering Practices

Developing and Using Models

Crosscutting Concepts

Stability and Change

Interdisciplinary Connections

Learning Objectives

Primary Learning Objectives

Students will be able to explain and use models to describe the photon path from the core of the sun to the surface of the sun.

Additional Learning Objective(s)

During this activity, the students will be demonstrating the following Scientific and Engineering Practices:

Asking questions and defining problems.
Developing and using models.
Planning and carrying out investigations
Analyzing and interpreting data
Engaging in argument from evidence
Obtaining, evaluating and communicating information.

During this activity, the students will be demonstrating the following Crosscutting Concepts:

Systems and system models
Structure and function
Stability and change

During this activity, the student will be demonstrating knowledge at the following Blooms Levels:

2, 3, 4, 5, 6 (depending on what part of the activity you are in)

During this activity, the students will be demonstrating knowledge at the following DOK Levels:

1, 3, 3, 4, 4 (depending on what part of the activity you are in)

During this activity and its extension, the students will be demonstrating the following Writing Standards:

Write arguments focused on discipline-specific content.

During this activity, its pre-reading, and its extension, students will utilize the following Reading Standard:

Follow precisely a multistep procedure when carrying out experiments, taking measurements, or performing technical tasks; analyze the specific results based on explanations in the text.

Procedures/Activities

1. Before class, make copies of Photon Reading Article, Photon Writing questions, Photon Exit Slip and Student Activity, “Photons in the Radiative Zone: Which Way is Out?” If you have not already done so, makes copies of the Handout “Standard Model of the Sun” and Student Text, “Models in Science”.

(Note: The Photon Reading Article, The Standard Model of the Sun and the Models in Science could be shown on a Smart-Board/projection unit, discussed as a class, and eliminate the need for photocopies/handouts. The Writing Questions and the Exit Slip questions can be handed out individually or can also be shown on a Smart-Board/projection unit for students to copy, answer and turn-in.)

Engage

Before beginning Student Activity, group class into pairs and hand out the Photon Reading Article. Have students read the article and as a class, discuss the information contained in the article. This will serve as an engaging activity to introduce the students to the photon.

Explore

After reading the article, individually have students think of a way to physically demonstrate how a photon exits the sun (and write it down). Then have them turn to their partner and discuss their strategy (noting any similarities and potential difficulties with each strategy). This will require students to "dig deeper" into the material.

Explain

With the students still grouped into the same pairs, hand the first two pages (the instructions and the maze) of Student Activity “Photons in the Radiative Zone: Which Way is Out?” to each student or each pair of students. Instruct them to complete the maze in pencil, since they may wish to make more than one try to the problem. Tell them to follow the instructions at the top of the page. They should draw only straight lines until they run into a barrier. At this point, they should use a protractor to determine the angle at which the line away from the barrier should be drawn. The angle of reflection should equal the angle of incidence. Again, the line of reflection should be drawn using a straight edge. The goal of the assignment is to find a way out of the maze.

Ask one student in each group to record the problem-solving processes on the student activity sheet they used to work their way out of the maze. They should record whether or not the process was successful and why it was or was not. They may begin to wonder whether or not it is possible to work their way out of the maze. Assure them that there are a number of ways to do this.

Elaborate

When they have worked their way out of the maze (or you have called time), bring them back together for a general class discussion. Have each group report to the class the successful and unsuccessful problem-solving processes they tried as they completed the assignment.

Display the Photon Writing Questions and have the students individually complete the Photon Writing Assignment. (This can be extended as a homework assignment.)

After reading the article, please explain how scientists can say that the light we see from the sun is from the past.
If the statement that the light from the sun is from the past is true, how does this apply to the light we see from the universe?

Engage

Explore

Explain

Elaborate

Display the Photon Writing Questions and have the students individually complete the Photon Writing Assignment. (This can be extended as a homework assignment.)

After reading the article, please explain how scientists can say that the light we see from the sun is from the past.
If the statement that the light from the sun is from the past is true, how does this apply to the light we see from the universe?

Learning Activity (Before)

Learning Activity (During)

Learning Activity (After)

Assessment Strategies

Evaluate

Review the characteristics and the purpose of a good scientific model (Models in Science) and follow this with questions similar to the following:

1. In the maze model that you worked on

What do the holes model?
What do the lines model?
Why is the maze circular?
In what way(s) is the maze a good model for the path of a photon in the radiative zone of the sun?
In what way(s) is this model not accurate?

2. Critique this model of the sun’s radiative zone. Was it a good model, an adequate model, or a poor model? Defend your rating of the model.

3. (Elaborate) Divide the class into teams of four students to design another, perhaps better, model for the path of a photon in the radiative zone of the sun. Have the students do the activity over (record data on the Student Activity sheet) with the new model. Have each group decide if the old model or the new model did a better job at representing the path progression. Make sure they have data to defend their choice.

4. (Evaluate) A more formative assessment option is the Photon Exit Slip. (Choose one or both of the questions below to use as an exit slip). Have students turn in before they leave the class.

What is solar energy and how is it formed?

Solar energy is derived from the sun in the form of solar radiation. Solar energy essentially created by a massive fusion reaction. Technically known as nuclear fusion, this process releases an incredible amount of energy in the form of light and heat. +[H₂+ H₂ à He + energy (heat and light)]

Advanced (4/3)	Meets all the proficient criteria + show an example of a fusion in the sun and incorporate the release of energy correctly in the equation.
Proficient (3/3)	Explain solar energy. Explain what process creates solar energy. Incorporate words: heat, light, energy
Progressing (2/3)	Meets 2 of the 3 proficient criteria
Beginning (1/3)	Meets 1 of the 3 proficient criteria
Does not meet (0/3)	Meets 0 of the 3 proficient criteria / does not answer question

How long does it take for the photon made in the core of the sun to reach the surface?

This varies on the random walk of the photon and the density of the material in each of the suns layers. If the length of the walk is 0.1 mm then the time it takes to reach the surface is 500,000 years. If the length of the walk is 1cm then the time it takes to reach the surface is 5000 years. +[core, (radiative zone, conductive zone), photosphere, chromosphere, corona]

Advanced (4/3)	Meets all the proficient criteria + states 4 basic layers of sun that the photon travels through
Proficient (3/3)	Explain how random walk affects length of exit time. Explain the exit time of a 0.10 mm walk length and a 1.0 cm walk length. Incorporate words: photon, density, random walk
Progressing (2/3)	Meets 2 of the 3 proficient criteria
Beginning (1/3)	Meets 1 of the 3 proficient criteria
Does not meet (0/3)	Meets 0 of the 3 proficient criteria / does not answer question

Acceleration and Intervention

Acceleration

Have the students create a presentation utilizing a presentation program (Power Point, Prezi, etc.) that compares the old model vs the new model of the photon emission through the radiative zone. Ensure that the students choose which model they feel is the better model, provide data that supports their claim, and be able to defend their position.