Back to Activities SGS sodis

SoDis - Harnessing the Sun's Power to Purify Water!

Experience directly the usefulness of UV rays as a possible means of disinfecting water in remote communities. It is important to note that the concepts of purifying, disinfecting, and filtering, among others, are different and complementary to reduce the chances of consuming contaminated water. In this activity, we will explore the SODIS (Solar Disinfection) method, a cost-effective and efficient way to treat water using solar energy and transparent bottles. By understanding how specific UV rays from sunlight inactivate harmful viruses and bacteria, you'll learn how to protect yourself and others by harnessing the sun's natural power. Become a champion of clean water and make a difference in your community!

Develop these Key Competencies:


  • Critical Thinking: Analyze how solar energy and specific UV rays can be utilized for water treatment.
  • Systems Thinking: Understand the impact of clean water on communities and the environment.

Materials needed


  • Transparent bottle (preferably PET)
  • Tap water
  • Sunny outdoor area with direct sunlight
Activity Description


Step 1: Safety First

  • Before we begin, remember to protect yourself from the sun's rays. Never look directly at the sun, even with glasses.

Step 2: Fill and Shake the Bottle

  • Fill the transparent bottle three-quarters full with tap water.
  • Close the bottle securely and shake it vigorously for 20 seconds.

Step 3: Fill and Wait

  • Fill the bottle to the top with more water, leaving space for expansion.
  • Close the bottle tightly again to prevent leaks.

Step 4: Harness the Sun's Power

  • Find an outdoor area with direct sunlight and place the closed bottle on a surface exposed to the sun.

Step 5: Exercise Patience

  • For partly cloudy days, wait 48 hours for the SODIS method to work its magic.
  • On sunny days, you only need to wait 6 hours to achieve safe water.



The SODIS method cannot be used on rainy days, as the absence of direct sunlight may compromise its effectiveness.



Explain how UV rays from the sun inactivate viruses and bacteria during the SODIS water treatment.



The SODIS method is a simple yet powerful water treatment technique. It relies on solar energy and transparent bottles, preferably PET, which allow specific UV rays from sunlight to deactivate harmful viruses and bacteria in the water. This economical and easy-to-implement method is endorsed by the World Health Organization for household use.


Additional Activities:

Take the initiative to prepare a proposal for implementing the SODIS method in a nearby community. Highlight its benefits, potential impact on clean water availability, and potential for positive change in people's lives. Be a Solar Superhero and lead a healthier and sustainable future!


Additional activities

Prepare a proposal to implement the SoDis (Solar Disinfection) method in a nearby community.

Relevant information if you are facilitating

This activity empowers young participants to become Solar Superheroes and clean water champions using the power of sun. Encourage critical thinking as they explore the SODIS method and its significance in water treatment. Foster systems thinking by discussing how access to clean water can positively impact communities and the broader environment. By understanding the power of solar energy to disinfect water, they become agents of change in promoting a healthier and more sustainable world.

Time needed

48 hours

Age range

  • 15 and above

Useful links


We are waiting for you!

Please note that you can participate in this activity, but first, you need to log in.

Time needed

48 hours

Age range

  • 15 and above

Useful links