Environmental Monitoring

Human activity can impact the environment in a variety of ways, ranging from air or water pollution to the destruction of animal habitats. This lesson plan will allow your students to explore how some of these impacts can be measured electronically using the parts in the Electronic Sensors Kit. You can decide whether you would like your students to choose from the following suggested topics, think of their own topic, or focus on a single activity for the entire class. Links to related Science Buddies project ideas provide more background information about each topic.

• Light pollution/air quality: the kit contains a light sensor called a photoresistor. A photoresistor is a type of resistor whose resistance depends on light. This resistance can be measured with a multimeter and used to determine the brightness of a light source like in the projects How Does the Intensity of Light Change with Distance? or How Bright Is Your Glow Stick? Measure It!. You can measure how airborne particulate matter (smog, smoke, etc.) affects the light sensor reading, or how artificial lighting affects the light sensor reading outdoors at night. How does human activity impact light levels? How does this change in light affect plant and animal life?
• Water quality: you can also use the light sensor to measure water quality. How much light water absorbs depends on its color (darker water will absorb more light). The projects How Do You Take Your Tea? Make a Simple Electronic Device to Measure the Strength of Tea, How Blue is Your Sports Drink? and Adsorption: Dyeing Fabrics with Kool-Aid all make use of this fact. Water with suspended particles will scatter more light, as shown in From Turbid to Clear: How Flocculation Cleans Up Drinking Water. You can even use chemical reactions to cause water's color to change based on its pH, as shown in Get Energized with Cellular Respiration! and Dealing with Diabetes: The Road to Developing an Artificial Pancreas. Can your students use this information to measure water samples from a classroom aquarium or a local body of water? How does human activity affect the water quality?
• Conductivity meter: the chemical makeup and moisture content of a material can influence its electrical conductivity. The project Electrolyte Challenge: Orange Juice Vs. Sports Drink explores this phenomena with sports drinks and electrolytes, but you could do this experiment with wet soil instead. How does the soil's moisture content affect its conductivity? How does human activity like deforestation or irrigation affect soil moisture, and what effect does this have on plant and animal life?
• Water level detector: a circuit can be used to detect the presence (or absence) of water, as shown in Green Technology: Build an Electronic Soil Moisture Sensor to Conserve Water. This can be useful in a house, for example to detect an overflowing sink or a flooding basement. What about monitoring water levels in the environment? For example, detecting whether a pond has dried up, a reservoir is full, or a river has overflowed its banks? How does human water consumption affect water levels in the environment?

This is a very open-ended lesson. While there are specific instructions for building each circuit, how they use the circuit will be up to the students. Depending on your students' prior knowledge, you will need to decide what material you cover in class and/or what you assign as background reading material.