Science project

How Right Is Rain?

Difficulty Level




Safety Issues

Do not drink untreated rainwater.

Material Availability

All necessary materials are readily available, as long as it rains.

Project Time Frame

6-8 weeks


This project looks at the processing of rainwater.  

The goals of this project are: 

  1. To determine the properties of rainwater
  2. To examine the techniques for harvesting rainwater.
  3. To outline the economic advantages of collecting rainwater. 

Materials and Equipment  

  • Computer with internet access.
  • Sterilized storage containers for holding rainwater samples
  • Magnifying glass
  • Microscope and related accessories (slides, medicine droppers, etc.)
  • Digital camera
  • Typical office/craft supplies (such as paper, pens & poster-board) 

All materials can be found in local stores or on ebay. 


The thing about rain is that there’s plenty of it in the world, but it doesn’t always appear in the right place at the right time. Rainwater processing (the harvesting, purification, storage and distribution of rainwater) is a significant industry that has led to many economic improvements. Here we look at rainwater collection and storage systems, as well as the purification processes that make rainwater drinkable. 

Research Questions 
  • What are the uses of rainwater?
  • What are the differences in the rainwater of different regions?
  • How is rain collected and stored?
  • How is rainwater purified?
  • How do companies make money from rainwater?  
Terms and Concepts to Start Background Research
  • Catchment System
  • Groundwater recharge
  • Irrigation
  • Rainwater
  • Water purification 

Experimental Procedure 

  1. Read overviews of relevant topics (see bibliography below and terms listed above).
  2. Design your own rainwater harvesting system, or use and existing system, such as your roof gutters, to collect rainwater.
  3. Look at rainwater samples under a microscope, and compare them to other water samples, such as tap water, bottled water, or rain samples from other locations.
  4. Purify the rainwater and reanalyze it, again comparing it to other water samples.
  5. Carefully record all observations. Describe which purification system(s) you used.
  6. Design a taste test of drinkable water samples to learn about consumer preferences.
  7. Interpret your findings in a detailed report.
  8. Show results visually, using charts and graphs.
  9. Display any interesting photos taken throughout the course of the experiment.
  10. Invite your science fair visitors to take a taste test. 

Bibliography (All about our water supply)

Wiki Topic: “Rainwater Harvesting”

Internet searches of your own choosing: Do a Google or Yahoo search for any of the terms listed above, and click on any results that interest you. Have fun surfing the net!


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Warning is hereby given that not all Project Ideas are appropriate for all individuals or in all circumstances. Implementation of any Science Project Idea should be undertaken only in appropriate settings and with appropriate parental or other supervision. Reading and following the safety precautions of all materials used in a project is the sole responsibility of each individual. For further information, consult your state's handbook of Science Safety.

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