Test Your Water
In this collaborative global project, students will use pH testing to determine the pH of the water in their school, or from a water source in the surrounding area
Water is essential to health and life. Providing access to clean water is a goal for everyone in the world, and is a UN Sustainable Development Goal. But just having access to water is not always enough. Even places with high functioning water systems face constant challenges. Unforeseen problems with infrastructure, flooding, and pollution can have detrimental effects on a community’s water. Creative solutions are needed as the demand for clean water continues to grow.
In this collaborative global project, students will use pH testing to determine the pH of the water in their school, or from a water source in the surrounding area. This type of testing can provide valuable information about the condition, health, and impact of the water. One issue facing many cities and towns around the world is the presence of lead in drinking water, which is often related to the acidity of the water. A low pH does not mean there is lead in the water, but it does mean that the condition exists for lead to leach into the water if the pipes are made from lead. By comparing the pH of local water, students are able to think about possible reasons for and implications of the different pH findings. Gathering data of this kind allows students to recognize how organisms, places, and events shape our world.
Build Background Knowledge
Use the strategies and resources below to prepare for your discussions and data collection.
- Engage students in the concept of acids and bases by asking students to describe how Lemonade and Milk taste and feel different in your mouth.
- Watch the video Acids and Bases, and have students complete the Spotlight on Strategies That Sums it Up to summarize what they have learned.
- If time allows, demonstrate the effect of acids by placing one 2cm piece of chalk in a small cup of vinegar (pH ~2-3) and another in a small cup of water (likely pH ~7), and let both sit overnight. Have students observe the two cups and discuss the results the next day.
- Review the following material with students to connect acidity to water issues such as lead in drinking water:
- pH value tells us if water is “hard” or “soft”. The pH of pure water is 7 (neutral, not acidic or alkaline). In general, water with a pH lower than 7 is considered acidic. Water with a pH greater than 7 is considered basic or alkaline. The pH range considered safe or normal for surface water systems is 6.5 to 8.5, and the pH range for groundwater systems is between 6.0 to 8.5.
- Another important factor is Alkalinity, which is a measure of the capacity of the water to resist a change in pH that would tend to make the water more acidic.
- The measurement of alkalinity and pH is needed to determine the corrosiveness of the water. Corrosive water can leach out heavy metals like lead which can cause human health problems.
- Provide the opportunity for students to gather water samples from around the school, including water fountains, classroom faucets, bathroom faucets, etc. Encourage students to also collect samples from nearby streams or ponds if accessible. Make sure students carefully label all samples with the source.
- Introduce students to the common test for pH, a wide range (1-14) litmus paper and provide or post an image that shows the range. Display and review instructions before testing any water samples.
- Facilitate student testing of the pH of all water samples by using the universal pH litmus paper. Record pH of all samples for entering into the Global Labs Report Form
* Encourage safety by having students wear goggles or safety glasses, and reinforcing the rule of no tasting the water samples.
- Ask students to photograph the water source together with the corresponding pH number (Be sure the number is prominent and clear in the photograph).
- Ask students to upload the image into the Globallab database and to complete a corresponding Report Form.
- Encourage students to view and analyze other submissions from around the world.
- Host a discussion on the corrosion and leaching of heavy metals such as lead by acidic water.
- Use the video Don’t Drink the Water to support discussion on how a community is affected when high levels of lead is found in drinking water.
- Project Author