Chemistry & Materials Science
From fizzing reactions to glowing colors, chemistry reveals how matter transforms — and smartphones can help us see it. This chapter explores chemical and material behavior using simple tools, common substances, and phone-based sensors.
With a camera, light sensor, or thermal app, you can track color changes, gas production, or heat flow in real time. From pH testing to fluorescence, these experiments make chemistry visual, measurable, and engaging — no lab coat required.
Color-Based Analysis (Indicators, Absorbance, Fluorescence)
Color Chemistry: Smartphone-Based pH and Water Quality Analysis (CHEM-01)
Sensors Used: Camera
What’s Measured: pH level, water hardness, nitrate, or other indicators via colorimetric change
Description
Color changes in chemistry are more than just dramatic—they are rich with measurable information. In this experiment, students explore acid-base chemistry and water quality through the lens of colorimetry, using only simple materials and the camera of a smartphone. By preparing common household acids and bases such as lemon juice, vinegar, baking soda, and soap, and adding a colorimetric indicator like red cabbage extract or a universal indicator solution, a vivid spectrum of pH-dependent color shifts is created in transparent containers. Students then photograph the samples under consistent lighting and analyze the resulting colors using either a color analysis app or by manually reviewing RGB values. This data allows them to build a visual pH scale and to estimate the acidity or basicity of unknown solutions with surprising accuracy. The method can be extended to commercial water quality test strips for detecting substances like nitrate, chlorine, water hardness, or heavy metals. By dipping test strips into samples, photographing them against a white background, and extracting color information from the images, students can perform semi-quantitative environmental analysis with everyday tools. This experiment blends analytical chemistry, optical physics, and environmental science, making the hidden chemical dynamics of everyday liquids both visible and measurable through creativity, curiosity, and light.**
Beer-Lambert in Your Pocket: Measuring Light Absorption (CHEM-02)
Sensors Used: Camera, Light Sensor App, Flashlight
What’s Measured: Light absorbance vs. concentration (Beer-Lambert Law)
Description
The deeper the color of a solution, the more light it absorbs—and with a smartphone, this relationship becomes measurable and tangible. In this experiment, students explore the Beer-Lambert Law, which states that the absorbance of light is directly proportional to the concentration of a solute in solution. Using a smartphone flashlight as a controlled light source, students shine light through a series of transparent containers filled with solutions of increasing concentrations, using colored liquids like food dye, tea, or potassium permanganate. A second smartphone equipped with a light sensor app is positioned on the opposite side to measure the transmitted brightness through each sample. By recording the light intensity for each solution, calculating absorbance, and plotting absorbance against concentration, students can produce a calibration curve that demonstrates the linear relationship predicted by the Beer-Lambert Law. With careful calibration, this simple setup even allows for the estimation of unknown concentrations—essentially transforming a smartphone into a pocket-sized spectrophotometer. Through this colorful and accessible experiment, core concepts of optics, absorption, and quantitative analysis in chemistry come vividly to life.**
Detecting Fluorescence with UV Light (CHEM-03)
Sensors Used: Camera, (Optional: UV Filter or Blue Light Filter)
What’s Measured: Fluorescence emission under ultraviolet illumination
Description
Some substances glow under ultraviolet light—not because they are hot, but because they fluoresce, emitting visible light after absorbing invisible UV radiation. In this experiment, students use a UV lamp or UV flashlight to illuminate common fluorescent materials such as tonic water (which contains quinine), highlighter ink, fluorescent minerals, or laundry detergents. Using the smartphone’s camera, students can capture the emitted glow, creating striking visual records of the phenomenon. For even clearer and more vivid images, a UV-blocking or blue-light filter can be placed over the lens to better isolate the fluorescent emission from background glare. Students are encouraged to document and compare the intensity, color, and quality of fluorescence across different materials, noting variations in brightness and hue. This simple yet captivating experiment introduces key concepts of electronic excitation and emission, offering a vivid and accessible entry point into the world of photochemistry and the study of molecular energy levels.**
Reaction Energy (Heat or Combustion)
Measuring Heat in Chemical Reactions: Exo vs. Endothermic (CHEM-04)
Sensors Used: Internal Temperature Sensor, Thermal Imaging Camera (e.g., CAT S60)
What’s Measured: Temperature change (ΔT) during chemical reactions to classify enthalpy change (ΔH)
Description
Some chemical reactions release heat into their surroundings, while others absorb it—and with a smartphone, students can measure the difference directly. In this experiment, thermal energy flow during familiar reactions is investigated using either the phone’s internal temperature sensor or a thermal imaging camera. Students begin by selecting reactions known to show thermal effects, such as vinegar combined with baking soda (a mildly endothermic reaction), hand warmers or iron oxidation packs (strongly exothermic), or salt dissolved in ice water (strongly endothermic, producing dramatic cooling). They record the temperature before, during, and after each reaction, carefully noting any rises or drops. When using an infrared camera, students can also visualize the evolving heat patterns in real time, making energy transfer dramatically visible. This experiment bridges chemistry and thermodynamics, providing a hands-on way to explore the nature of enthalpy changes (ΔH) and showing how chemical energy is either released or absorbed—all with tools already available in a smartphone lab.**
Capturing Fruit Fireballs with High-Speed Photography (CHEM-05)
Sensors Used: High-Speed Camera or Smartphone with Slow-Motion Mode
What’s Measured: Visual observation of combustion speed, flame shape, and reaction intensity
Description
Fruit isn’t usually thought of as flammable, but under the right conditions, it can produce a spectacular burst of fire. In this dramatic experiment, students introduce small pieces of fruit—such as grapes, orange peels, or banana chips, all rich in sugars or volatile oils—into a flame and observe rapid combustion reactions. Using a smartphone’s slow-motion or high-speed video mode, they can capture the moment of ignition in vivid detail, revealing how quickly stored chemical energy transforms into heat and light. The resulting “fruit fireballs” offer a stunning visual demonstration of combustion chemistry, reaction rates, and energy release. As sugars and volatile compounds vaporize and ignite almost instantaneously, students can see the explosive power hidden inside everyday organic matter. Safety precautions are essential: this experiment must be conducted in a well-ventilated area, away from flammable materials, and under appropriate supervision with protective equipment. It’s chemistry at its most kinetic and captivating—a fiery fusion of food science, thermodynamics, and high-speed imaging.**
References:
[1] “Fruit Fireballs,” https://www.thenakedscientists.com/get-naked/experiments/fruit-fireballs
Reaction Kinetics and Gas Production
Watching Reactions in Time: Rate of Reaction with Video (CHEM-06)
Sensors Used: Smartphone Camera (Video or Time-Lapse Mode)
What’s Measured: Visual progression of reaction rate over time
Description
Chemical reactions aren’t just about what changes — they’re about how fast those changes unfold. In this experiment, students use their smartphone’s video or time-lapse capabilities to explore reaction kinetics by capturing the progression of a reaction over time. They begin by choosing a reaction with a strong, visible output, such as a color change, bubble formation, or foam expansion. A particularly popular choice is the “elephant toothpaste” demonstration, where hydrogen peroxide reacts with yeast or potassium iodide to produce a dramatic, foamy eruption of oxygen bubbles. By recording the entire reaction, students can later analyze how quickly the visual effect builds, identifying key phases of acceleration and slowing. For deeper insight, they can repeat the reaction while varying conditions such as concentration, temperature, or the presence of catalysts, allowing a direct comparison of how these factors influence reaction speed. Frame-by-frame, this experiment transforms chemical change into measurable, observable data, offering an accessible and vivid introduction to the principles of reaction kinetics.**
Listening to Reactions: Gas Production via Audio and Video (CHEM-07)
Sensors Used: Microphone, Camera
What’s Measured: Rate of gas production via bubbling sounds and balloon inflation
Description
Some chemical reactions don’t just bubble — they create a soundtrack. In this experiment, students use a smartphone’s microphone and camera to capture and analyze the production of gas during a reaction. A classic setup involves combining vinegar and baking soda inside a bottle and stretching a balloon over the opening. As the reaction proceeds and carbon dioxide gas is produced, the balloon gradually inflates. Students can document the reaction visually by recording video footage of the balloon’s expansion, while simultaneously capturing audio to analyze the bubbling sounds. Using apps like Phyphox or other audio visualization tools, they can examine the frequency, intensity, and pattern of the bubbles over time. This multi-sensory approach turns gas evolution into both a visual and acoustic dataset, linking chemical kinetics with principles from acoustics and fluid dynamics. It’s a creative, engaging way to “listen in” on a reaction as it unfolds — and to reveal patterns hidden in the noise.**
Capillarity and Wicking
Capillary Action in Paper Towels (CHEM-08)
Sensors Used: Camera, (Optional: Thermal Camera)
What’s Measured: Wicking height and speed of fluid through porous materials
Description
Water can climb — and this experiment reveals how. Using just a smartphone and simple household materials, students explore capillary action: the ability of liquids to move through narrow spaces without external force. The setup is straightforward: dip the edge of a paper towel, coffee filter, or cardstock into a container filled with colored water and observe how the liquid steadily wicks upward. By recording the process with a smartphone camera, students can measure the height reached and the speed of the moisture front over time. If available, a thermal camera offers an additional dimension by visualizing the temperature differences between wet and dry areas, making the fluid movement even more striking. By comparing different materials, students can investigate how porosity, fiber structure, adhesion, and surface tension influence fluid transport. This accessible experiment connects everyday observations to key principles in chemistry and materials science, revealing the hidden physics behind something as simple as a rising drop of water.**