Environmental Physics
Environmental physics is where physical law meets everyday experience — in sunlight and shadow, air pressure and rainfall, heatwaves and breezes. With nothing more than a smartphone, students become environmental investigators, collecting real-world data on light, sound, temperature, altitude, gas flow, and even invisible radiation.
This chapter explores how mobile devices transform into portable observatories — functioning as weather stations, barometers, spectrometers, microclimate mappers, and even acoustic rain gauges. The experiments connect core physics concepts — like fluid pressure, electromagnetic radiation, wave scattering, and phase transitions — to the dynamic systems of our atmosphere, buildings, and biosphere.
Most of these activities can be done on a walk, in a park, or even from a balcony. The goal: to turn ordinary environments into sources of scientific insight — and build a deeper awareness of the invisible forces shaping our planet.
Atmospheric Pressure & Altitude Physics
Pressure vs. Altitude: Turning Stairs into a Barometer (ENVP-01)
Sensors Used: Barometric Pressure Sensor, (Optional: GPS or Altimeter)
What’s Measured: Atmospheric pressure change with vertical displacement
Description
The higher you go, the less atmosphere is above you — and your smartphone can detect it. In this experiment, use your phone’s barometric pressure sensor to explore how air pressure drops with altitude, even over short vertical distances.**
Walk up stairs, climb a hill, or ride an elevator, recording pressure at each level or interval. Try it both indoors and outdoors, and compare readings between floors or stairwells in a building. Even small height changes create measurable pressure shifts — a real-world application of the hydrostatic equation.
Plot pressure vs. height or floor number, and compare your data to standard models — or derive your own linear or logarithmic relationship. You can even estimate elevation gain from pressure alone — no GPS required.
Vacuum Container Boiling Point Drop (ENVP-02)
Sensors Used: Thermal Sensor or Infrared Camera, (Optional: Barometric Pressure Sensor)
What’s Measured: Boiling point of water at reduced pressure
Description
Water doesn’t need to be 100°C to boil — not if the air pressure is low enough. In this experiment, pour hot (but not boiling) water into a vacuum-insulated food container with a pressure release valve. Seal the lid, then gradually reduce the pressure using the built-in pump.**
Watch closely as bubbles begin to form — water boils at a lower temperature under reduced pressure. Use a thermal sensor or infrared camera to track the water temperature as boiling begins.
This striking demo reveals the connection between ambient pressure, vapor pressure, and boiling point — a key concept in both thermodynamics and weather systems.
Boiling Point vs. Altitude Collaboration (ENVP-03)
Sensors Used: Thermal Sensor, Infrared Camera, (Optional: Barometer or GPS)
What’s Measured: Boiling point of water at different altitudes
Description
Water doesn’t boil at the same temperature everywhere — it depends on elevation and air pressure. In this collaborative experiment, students in different locations measure the boiling point of water using a smartphone thermometer or IR camera, then compare their results across regions.**
Use a boiling point calculator or phase diagram to relate each measurement to altitude or atmospheric pressure. For an added challenge, reverse-engineer the local pressure from your boiling data and compare it with current weather reports.
This is a powerful demonstration of how phase changes, air pressure, and altitude are deeply connected — and how science becomes even more engaging when it’s done across the map.
References:
[1] “Boiling Point Calculator,” https://www.omnicalculator.com/chemistry/Boliling-point
Pressure-Temperature Profiles in Water (ENVP-04)
Sensors Used: Barometric Pressure Sensor, Temperature Sensor (internal or external)
What’s Measured: Pressure and temperature as a function of water depth
Description
Water behaves differently as you dive deeper. In this experiment, place your smartphone in a sealed waterproof pouch and submerge it in a lake, pool, or deep bathtub. Use built-in or connected sensors to record pressure and temperature at various depths.**
Graph your results to create a vertical profile of the water column. You’ll observe how pressure increases and temperature varies with depth — a great way to explore concepts like fluid statics, thermal gradients, and lake stratification in real-world settings.
It’s simple, splash-proof science that reveals the layered physics beneath the surface.
UV, IR, and Environmental Light Exposure
Infrared and Ultraviolet Exploration (ENVP-05)
Sensors Used: Infrared Camera, UV Sensor, (Optional: Camera Filters or UV Flashlight)
What’s Measured: Infrared and ultraviolet radiation beyond the visible spectrum
Description
The world doesn’t stop at visible light. In this experiment, use infrared and ultraviolet sensors, camera filters, or smartphone apps to explore radiation just outside the human eye’s range.**
Point your IR tools at heat sources like electronics, warm skin, or sunlight to reveal invisible thermal patterns. Use a UV flashlight or natural sunlight to investigate fluorescence, UV exposure, or material sensitivity.
This spectral adventure opens a window into the extended electromagnetic spectrum, linking physics with public health, environmental awareness, and the hidden structure of light all around us.
References:
[1] “Infra-red and ultraviolet radiation,” http://practicalphysics.org/waves-Infra-red.html
UV and Sunlight Logging: Watching the Sky with a Sensor (ENVP-06)
Sensors Used: Light Sensor, UV Sensor, (Optional: UV Meter App or Camera)
What’s Measured: Sunlight intensity and UV exposure over time and conditions
Description
Sunlight may feel steady, but it’s constantly changing. In this experiment, use your smartphone’s light sensor or a UV meter app to track sunlight or UV intensity throughout the day and under different conditions.**
Record readings at regular intervals — try comparing morning vs. noon, sunny vs. cloudy skies, indoor vs. outdoor, or direct light vs. shade. Graph your results to see how solar angle, weather, and surface reflection affect exposure.
This experiment connects physics to everyday life: from solar energy and vitamin D to skin safety and climate awareness — all through the lens of sunlight.
UV Transmission Through Materials
Goal: Measure how much UV light passes through various materials with UV-sensitive materials or a dedicated sensor (like GUVA-S12SD) for ultraviolet. Setup: Place materials (plastic wrap, sunglasses, tinted glass, sunscreen film) between the UV light source (sunlight or UV LED) and the sensor. Concepts: UV absorption, optical filtering, safety applications Twist: Can correlate readings to SPF ratings or glass types (e.g. windows vs. quartz).
Measuring Effectiveness of Sunscreens
Goal: Determine how well different SPF creams block UV. Setup: Apply sunscreens on transparent plastic film and place them between sensor and UV source.. Output: Measure reduction in sensor voltage to evaluate UV attenuation. Concepts: Absorption spectrum, health applications, chemistry of sunscreens The “Sunscreen Tester” could be a flagship cross-disciplinary project combining optics, health, and chemistry!
Detecting Gases and Airborne Particles
CO₂ Detection with “Invisible Gas” Setup (ENVP-07)
Sensors Used: Infrared Camera, (Optional: Thermal Sensor or Visual Contrast Setup)
What’s Measured: Movement and behavior of carbon dioxide gas
Description
Carbon dioxide is invisible — but with the right setup, you can see it in action. In this experiment, generate CO₂ using a simple reaction like baking soda and vinegar, and observe how the gas flows, settles, or displaces air.**
Try using thermal contrast by placing a warm background behind the gas, or use an infrared camera to reveal how this dense gas collects in low areas. Alternatively, place a cold surface in humid air to visualize CO₂ using condensation trails.
It’s a vivid way to observe the weight and motion of a major greenhouse gas, linking chemistry, thermodynamics, and environmental physics in one eye-opening demo.
References:
[1] “Seeing Invisible”, https://www.thenakedscientists.com/get-naked/experiments/seeing-invisible
Air Pollution Visualization with Light Scattering (ENVP-08)
Sensors Used: None required (light source and visual observation)
What’s Measured: Light scattering due to suspended particles (aerosols)
Description
Can you simulate smog in a glass? In this visual experiment, use light scattering to model how aerosols affect visibility and sunlight. Shine a laser pointer or bright LED through a clear container filled with water, and slowly add small amounts of milk to introduce fine particles.**
As particle concentration increases, the beam becomes visible — thanks to Tyndall or Rayleigh scattering — just like sunlight filtering through haze or smog. The beam’s growing visibility offers a simple yet powerful metaphor for air pollution, particulate matter, and their impact on atmospheric optics.
Seismic and Acoustic Monitoring
Seismic Detection: Feeling the Earth (or Your Desk) Move (ENVP-09)
Sensors Used: Accelerometer
What’s Measured: Vibrations and acceleration patterns from local motion
Description
Your smartphone’s accelerometer is sensitive enough to detect even tiny vibrations — including those caused by footsteps, furniture bumps, or even earthquakes. In this experiment, place your phone on a solid surface and use a seismograph app to record motion data.**
Simulate local vibrations by tapping the table, jumping nearby, or having someone walk past. Record the resulting waveform and analyze its shape and amplitude. Discuss how this relates to how real seismic events are measured, filtered, and interpreted.
Bonus: If you’re in a tectonically active region, leave your phone running in the background — it might just capture the Earth’s subtle rumblings in real time.
Acoustic Rainfall Detection: Listening to the Weather (ENVP-10)
Sensors Used: Microphone
What’s Measured: Rainfall intensity through sound amplitude and frequency
Description
What if your phone could listen to the rain and measure it? Inspired by research in acoustic hydrology, this experiment uses your smartphone’s microphone to detect and analyze the sound of rainfall.**
Place your phone under a surface that amplifies raindrop impacts — such as a metal plate, umbrella, or roof overhang. Use a waveform or spectrogram app to record the sound profile. Larger drops create sharp, loud spikes, while gentle drizzle results in a softer, more even distribution.
By analyzing volume (amplitude) and frequency, you can estimate rainfall intensity — no rain gauge required. It’s a creative and surprisingly accurate way to explore the physics of precipitation and sound.
References:
[1] “Fraunhofer researchers have developed an acoustic method to measure rainfall intensity…”, https://www.heise.de/news/Forschung-Wie-sich-Regenintensitaet-akustisch-messen-laesst-10338461.html
Urban Mapping & Wireless Fields
Microclimate Mapping: Physics in the Urban Wild (ENVP-11)
Sensors Used: Temperature Sensor, Light Sensor, Humidity Sensor, (Optional: GPS)
What’s Measured: Environmental conditions across varied microclimates
Description
Step outside, and you’re surrounded by microclimates — small pockets of air with their own temperature, light, and humidity. In this experiment, walk, bike, or ride through contrasting environments — a shaded park, sunlit street, inside a vehicle, or urban concrete zones — while using your smartphone to log environmental data.**
Record temperature, humidity, and light levels with a sensor app, then map and compare the conditions across locations. Why is it cooler beneath trees? How hot does it get in a parked car? How does pavement intensify heat?
This experiment connects physics with urban design, climate science, and ecology — revealing how the built environment shapes the conditions we live in every day.
Mapping “Electrosmog”: Visualizing Wireless Signals with Long Exposure (ENVP-12)
Sensors Used: Wi-Fi Signal Meter, Camera (Long Exposure Mode)
What’s Measured: Spatial distribution of wireless signal strength
Description
Wireless signals are all around us — but usually invisible. In this creative experiment, turn your smartphone into a tool for visualizing electromagnetic fields. Use one phone to display real-time Wi-Fi signal strength, color-coded or graphically, and another to take a long-exposure photo while walking slowly through a darkened room.**
The result is a glowing image that traces the strength of wireless signals through space — revealing hotspots, shadowed zones, and the complex geometry of “electrosmog” indoors.
It’s a striking blend of art and physics, offering a powerful way to explore how EM radiation behaves in built environments — and how we might design around it.
Capstone / Research Extension
Detecting Micro-Movements — Earthquake Sensors from Simple to Sophisticated (ENVP-13)
How small of a movement can you detect using nothing more than lasers, mirrors, and a smartphone? This multi-stage experiment invites students to push the limits of precision measurement by constructing increasingly sensitive vibration detectors. Along the way, they explore key physics concepts such as inertial frames, wave interference, and optical amplification — culminating in a hands-on understanding of the same principles used in professional seismology and even gravitational wave observatories like LIGO.
The journey begins with a simple DIY seismograph: suspend a smartphone from the ceiling like a pendulum, and aim a laser pointer upward at its camera. As the phone shifts from ambient vibrations or floor movement, the laser dot will drift across the image sensor. Students can use either motion sensors or camera-based tracking to log these shifts, exploring how resolution and frame rate limit sensitivity. This basic setup illustrates the principle of relative motion detection in inertial reference frames.
The next stage refines the design by replacing the smartphone with a suspended mirror. A laser pointer is directed at the mirror, and its reflection lands on a distant wall or a phone screen. Here, even the slightest rotations or tremors of the mirror translate into large, amplified shifts of the laser dot — a geometric magnification that introduces students to angular displacement and beam reflection. The setup becomes more sensitive but also more vulnerable to environmental factors like air drafts or table vibrations, highlighting the importance of isolation in precision measurement.
In the final stage, advanced students construct a simple Michelson interferometer using a laser diode, two mirrors, and a partially reflective beam splitter. When the device experiences tiny vibrations, the relative path length of the laser beams changes, shifting the interference fringes projected on a wall or camera. These fringe shifts can be analyzed to detect displacements on the nanometer scale — a stunning example of how sub-wavelength sensitivity is possible with basic optical tools. This portion of the experiment directly connects classroom science to cutting-edge research in gravitational wave detection.
Throughout the experiment, students are encouraged to compare the sensitivity of each stage, explore how temperature and air movement affect the readings, and practice isolating real signals from background noise. As an optional extension, a piezoelectric element can be introduced to apply controlled, repeatable vibrations and quantify each setup’s response.
Ultimately, this capstone experiment offers more than just a clever way to detect motion. It shows how physical insight, optical principles, and careful design can transform simple materials into scientific instruments capable of extraordinary precision — a modern echo of the ingenuity behind some of physics’ most profound discoveries.