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Solar Water Disinfection (SODIS)

Difficulty: Grade 6-8
Time: 45 - 60 mins
Categories:

In this lesson, we will learn about Solar Water Disinfection (SODIS) as a low-cost way to clean water. In the ‘Take Action’ section of this lesson, we’ll use a micro:bit and a plastic bottle of water to create our own SODIS timer!

Get Started
What this lesson includes
Lesson Content
Solar Water Disinfection
Real-World Example

Coding Tutorial
Block-based
Assessment
Triangulated Assessment Options
Educator Resources
Finished Code Link
Quickstart Guide

Looking for more resources? Look  here.

Learning Goals

  • Explain why access to clean water is important
  • Describe how people collect and clean water in countries with poor access
  • List the steps of SODIS and explain how it changes on sunny or cloudy days
  • Discuss the pros and cons of SODIS
  • Create a SODIS timer that uses variables and nested conditionals to track how long water has been exposed to sunlight and notify users when it is safe to drink

Materials

Get to Know the Content

  1. Make sure you’ve completed our ‘Getting Started with the Climate Action Kit’ course
  2. Review the lesson

Big Idea (20 minutes)

Learn about SODIS and its impact on community wellness!

Take Action (45 minutes)

See how SODIS is saving lives in Kenya and build your own SODIS timer with the Climate Action Kit! The timer will track how long a water bottle has been in the sun and will notify the community once it is safe to drink.

We've provided 3 ways students may build the project to support scaffolding and differentiation in your classroom: 'Use', 'Modify', and 'Create'.*

Activity Description
Use

Students will follow a step-by-step tutorial to build & use their SODIS timer. They will test how the timer works to track sunlight exposure.

Success Criteria

I can:

  • build a SODIS timer using the micro:bit
  • explain how the micro:bit detects light
  • explain how variables, conditional statements, and loops help track how long a water bottle has been in the sun

Resources

Tutorial
Final Code
Modify

Students will follow a step-by-step tutorial to build their SODIS timer. Then, they will change the code to learn how it works and complete a few challenges to show their understanding.

Success Criteria

I can:

  • build a SODIS timer using the micro:bit
  • tinker with pre-written code to learn how it works
  • explain how to use a variable and conditional statement to track how long a water bottle has been in the sun
  • write my own conditional statement to indicate when the water is safe to drink
  • create two new variables to ensure the timer works well on cloudy and sunny days

Resources

Tutorial
Final Code
Create

Students will work in small groups to design their own SODIS timer with the Climate Action Kit.

Success Criteria

I can build a SODIS timer with the Climate Action Kit that:

  • keeps track of how long water has been in the sun
  • clearly indicates when the water is safe to drink
  • works well on sunny and cloudy days

and uses at least:

  • one light sensor

Resources

Blank Project

*Irene Lee, Fred Martin, Jill Denner, Bob Coulter, Walter Allan, Jeri Erickson, Joyce Malyn-Smith, and Linda Werner. 2011. Computational thinking for youth in practice. Acm Inroads 2, 1 (2011), 32–37.

Use the following criteria to assess student learning. Students can:

Conversations

  • Discuss why access to clean water is important
  • Describe how people collect and clean water in countries with poor access and the important role women play in this process
  • List the steps of the SODIS process and its pros and cons
  • Identify the variable and conditional statement within the starter code and explain how they work together to track how long the water bottle has been in the sun (Use, Modify, Create)

Observations

  • Make predictions about what certain segments of the code are responsible for and test those predictions (Use, Modify)
  • Methodically test and debug their code to ensure it functions as intended (Modify, Create)

Products

  • Add comments to the code to demonstrate their understanding of each block (Use, Modify, Create)
  • Create a standard, compound, and/or nested conditional statement that represents a decision making point within their algorithm (Modify, Create)
  • Design their own prototype that satisfies provided criteria (Create)

Next Generation Science Standards

Grade 6-8

MS-ESS3-4 Construct an argument supported by evidence for how increases in human population and per-capita consumption of natural resources impact Earth’s systems.

MS-ETS1-1 Define criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions.

MS-ETS1-4 Develop a model to generate data for iterative testing and modification of a proposed object, tool, or process such that an optimal design can be achieved.

Computer Science Teachers Association Standards

Grade 6-8

2-CS-02 Design projects that combine hardware and software components to collect and exchange data.

2-CS-03 Systematically identify and fix problems with computing devices and their components.

2-AP-11 Create clearly named variables that represent different data types and perform operations on their values.

2-AP-12 Design and iteratively develop programs that combine control structures, including nested loops and compound conditionals.

2-AP-13 Decompose problems and subproblems into parts to facilitate the design, implementation, and review of programs.

2-AP-19 Document programs in order to make them easier to follow, test, and debug.

Common Core State Standards for Mathematics

Grade 6-8

6.EE.A.2 Write, read, and evaluate expressions in which letters stand for numbers.

6.EE.B.5 Understand solving an equation or inequality as a process of answering a question: which values from a specified set, if any, make the equation or inequality true? Use substitution to determine whether a given number in a specified set makes an equation or inequality true.

6.EE.B.6 Use variables to represent numbers and write expressions when solving a real-world or mathematical problem; understand that a variable can represent an unknown number, or, depending on the purpose at hand, any number in a specified set.

6.EE.B.8 Write an inequality of the form x > c or x < c to represent a constraint or condition in a real-world or mathematical problem. Recognize that inequalities of the form x > c or x < c have infinitely many solutions; represent solutions of such inequalities on number line diagrams.

7.EE.B.4Use variables to represent quantities in a real-world or mathematical problem, and construct simple equations and inequalities to solve problems by reasoning about the quantities.

United Nation’s Sustainable Development Goals

3: Good Health and Well-Being

5: Gender Equality

6: Clean Water and Sanitation

13: Climate Action

Common Career Technical Core Standards

STEM Cluster: Engineering & Technology Career Pathway

ST-ET 1.3 Use computer applications to solve problems by creating and using algorithms, and through simulation and modeling techniques.

ST-ET 2.1 Select and use information technology tools to collect, analyze, synthesize and display data to solve problems.

ST-ET 3.1 Use knowledge, techniques, skills and modern tools necessary for engineering practice.

ST-ET 3.2 Describe the elements of good engineering practice (e.g., understanding customer needs, planning requirements analysis, using appropriate engineering tools, prototyping, testing, evaluating and verifying).

ST-ET 3.4 Illustrate the ability to characterize a plan and identify the necessary engineering tools that will produce a technical solution when given a problem statement.

ST-ET 4.1 Explain why and how the contributions of great innovators are important to society.

ST-ET 4.2 Explain the elements and steps of the design process and tools or techniques that can be used for each step.

ST-ET 4.3 Describe design constraints, criteria, and trade-offs in regard to variety of conditions (e.g., technology, cost, safety, society, environment, time, human resources, manufacturability).

ST-ET 5.1 Apply the design process using appropriate modeling and prototyping, testing, verification and implementation techniques.

ST-ET 5.2 Demonstrate the ability to evaluate a design or product and improve the design using testing, modeling and research.

ST-ET 5.3 Demonstrate the ability to record and organize information and test data during design evaluation.

ST-ET 6.1 Apply the use of algebraic, geometric, and trigonometric relationships, characteristics and properties to solve problems.

STEM Cluster: Science and Math Career Pathway

ST-SM 1.1 Apply science and mathematics concepts and principles to resolve plans, projects, processes, issues or problems through methods of inquiry.

ST-SM 1.2 Use the skills and abilities in science and mathematics to access, share, and use data to develop plans, processes, projects and solutions.

ST-SM 1.3 Use the skills and abilities in science and mathematics to integrate solutions related to technical or engineering activities using the content and concepts related to the situations.

ST-SM 1.4 Explain the role of modeling in science and engineering.

ST-SM 1.5 Explain the use of models and simulation in hypothesis testing (i.e., the scientific method).

ST-SM 1.6 Communicate with others on inquiry or resolution of issues/problems in the global community.

ST-SM 2.1 Demonstrate the ability to recognize cause and effect when faced with assigned projects or issues.

ST-SM 2.4 Predict the outcomes based on data collected in a project or experiment.

ST-SM 2.9 Analyze change as a result of data differences and changing environmental values.

ST-SM 3.1 Evaluate the impact of science on society based on products and processes used in the real world.

ST-SM 3.2 Evaluate the impact of mathematics on society based on products and processes used in the real world.

ST-SM 3.3 Research how science and mathematics influence the professions and occupations supported by the STEM Career Cluster.

Information Technology Cluster: Programming & Software Development Career Pathway

IT-PRG 4.1 Employ tools in developing software applications.

IT-PRG 6.1 Explain programming language concepts.

IT-PRG 6.3 Demonstrate proficiency in developing an application using an appropriate programming language.

IT-PRG 6.4 Explain basic software systems implementation.

IT-PRG 7.1 Develop a software test plan.

IT-PRG 7.2 Perform testing and validation.

Agriculture, Food & Natural Resources Cluster: Power, Structural & Technical Systems Career Pathway

AG-PST 1.1 Select energy sources for power generation.

AG-PST 1.3 Investigate solutions to AFNR power, structural, and technical systems.

AG-PST 1.4 Design or modify equipment, structures, or biological systems to improve performance of an AFNR enterprise or business unit.