Mixtures & Solutions

Students are introduced to the differences between acids and bases and how to use indicators, such as pH paper and red cabbage juice, to distinguish between them. They learn why it is important for engineers to understand acids and bases.

Students define and classify alloys as mixtures, while comparing and contrasting the properties of alloys to those of pure substances. Students learn that engineers investigate the structures and properties of alloys for biomedical and transportation applications.

Students become product engineers in a bouncy ball factory as they design and prototype a polymer bouncy ball that meets specific requirements: must be spherical in shape, cannot disintegrate when thrown on the ground, and must bounce.

Students use a simple pH indicator to measure how much CO2 is produced during respiration, at rest and after exercising. They begin by comparing some common household solutions in order to determine the color change of the indicator.

To increase students' awareness of possible invisible pollutants in drinking water sources, students perform an exciting lab requiring them to think about how solutions and mixtures exist even in unsuspecting places such as ink. They use alcohol and chromatography paper to separate the components of...

Students learn about how dyes are extracted from organic material and use the engineering design process to test dyes using a variety of indicators to achieve the right color for their prototype. Students iterate on their dyes and use ratios and proportions to calculate the amount of dye needed to ...

Students make edible models of algal cells as a way to tangibly understand the parts of algae that are used to make biofuels. The molecular gastronomy techniques used in this activity blend chemistry, biology and food for a memorable student experience.

Students learn the function of the liver and how biomedical engineers can use liver regeneration to help people. Students test the effects of toxic chemicals on a beef liver by adding hydrogen peroxide to various liver and salt solutions.

Students build a saltwater circuit, which is an electrical circuit that uses saltwater as part of the circuit. Students investigate the conductivity of saltwater, and develop an understanding of how the amount of salt in a solution impacts how much electrical current flows through the circuit.

Students study the physical properties of different fluids and investigate the relationship between the viscosities of liquid and how fast they flow through a confined area. Student groups conduct a brief experiment in which they quantify the flow rate to understand how it relates to a fluid's visco...

Students measure the effectiveness of water filters in purifying contaminated water. They prepare test water by creating different concentrations of bleach (chlorine-contaminated) water. After passing the contaminated water through commercially available Brita® water filters designed to purify drink...

Students develop an understanding of the effects of invisible air pollutants with a rubber band and hanger air test and a bean plant experiment. They also learn about methods of reducing invisible air pollutants.

Students hypothesize whether vinegar and ammonia-based glass cleaner are acids or bases. They create designs on index cards using these substances as invisible inks.

Students create beams using Laffy Taffy and water, and a choice of various reinforcements (pasta, rice, candies) and fabricating temperatures. Student groups compete for the highest strength beam and measure flexure strength with three-point bend tests and calculations.

Students learn how to manipulate the behavior of water by using biochar, a soil amendment used to improve soil function. In this experiment, students solve the problem of standing water by troubleshooting, researching, and engineering possible solutions that speed water drainage through soil.

Students act as engineers to learn about the strengths of various epoxy-amine mixtures and observe the unique characteristics of different mixtures of epoxies and hardeners. Student groups make and optimize thermosets by combining two chemicals in exacting ratios to fabricate the strongest and/or mo...

Student groups construct simple conductivity probes and then integrate them into two different circuits to test the probe behavior in solutions of varying conductivity (salt water, sugar water, distilled water, tap water).

Students investigate the property dependence between concentrations and boiling point. In section 1, students first investigate the boiling point of various liquid solutions. In section 2, they analyze data collected by the entire class to generate two boiling point curves, one for salt solutions an...

Students explore how to create silver nanoparticles and use empirical data to make observations about their creation. Students learn about oxidation, reduction, and redox reactions in order to create a process for growing silver nanoparticles in the laboratory in a more efficient manner.

Students design and create their own nano-polymer smartphone case. Students choose their design, mix their nano-polymer (based in silicone) with starch and add coloring of their choice. While students think critically about their design, they embed strings in the nano-polymer material to optimize bo...

Students demonstrate the erythrocyte sedimentation rate test (ESR test) using a blood model composed of tomato juice, petroleum jelly and olive oil. They simulate different disease conditions, including rheumatoid arthritis, anemia, leukocytosis and sickle-cell anemia, by making appropriate variatio...

Students experiment with dyes, scatterplot graphs, and other analytic tools as part of an engineering design project geared towards developing their knowledge with chemical analysis.

To gain an understanding of mixtures and the concept of separation of mixtures, students use strong magnets to find the element of iron in iron-fortified breakfast cereal flakes. Through this activity, they see how the iron component of this heterogeneous mixture (cereal) retains its properties and ...

Students gain a better understanding of the different types of materials as pure substances and mixtures and learn to distinguish between homogeneous and heterogeneous mixtures by discussing an assortment of example materials they use and encounter in their daily lives.

To become familiar with the transfer of energy in the form of quantum, students perform flame tests, which is one way chemical engineers identify elements—by observing the color emitted when placed in a flame. After calculating and then preparing specific molarity solutions of strontium chloride, co...

Students continue the research begun in the associated lesson as if they were biomedical engineers working for a pharmaceutical company. Groups each perform a simple chemical reaction (to precipitate solid calcium out of solution) to observe what may occur when Osteopontin levels drop in the body.

Students work as biomedical engineers to find liquid solutions that can clear away polyvinyl acetate polymer "blood clots" in model arteries (made of clear, flexible tubing). Teams create samples of the "blood clot" polymer with different concentrations to discover the concentration of the model clo...

Students learn about the separation techniques of sedimentation and centrifugation and investigate whether blood is a homogeneous or a heterogeneous mixture. Working in groups as if they are biomedical researchers, they employ the scientific method and make observations about the known characteristi...

In the presence of water, citric acid and sodium bicarbonate (aka baking soda) react to form sodium citrate, water, and carbon dioxide. Students investigate this endothermic reaction. They test a stoichiometric version of the reaction followed by testing various perturbations on the stoichiometric v...

Through this lab, students are introduced to energy sciences as they explore redox reactions and how hydrogen fuel cells turn the energy released when hydrogen and oxygen are combined into electrical energy that can be read on a standard multimeter.

Students see and learn how crystallization and inhibition occur by making sugar crystals with and without additives in a supersaturation solution, testing to see how the additives may alter crystallization, such as by improving crystal growth by more or larger crystals.

Students learn how to classify materials as mixtures, elements or compounds and identify the properties of each type. The concept of separation of mixtures is also introduced since nearly every element or compound is found naturally in an impure state such as a mixture of two or more substances, and...

Students learn about the properties of solutions—such as ion interactions, surface tension and viscosity—as they make their own soap and shampoo and then compare their properties. Working as if they are chemical engineers, they explore and compare how the two surfactants behave in tap water, as well...

Building on an introduction to statics, dynamics free-body diagrams, combustion and thermodynamics provided by the associated lesson, students design, construct and test their own rocket engines using sugar and potassium nitrate—an opportunity to apply their knowledge of stoichiometry.