All biological cells require the transport of materials across the plasma membrane into and out of the cell. By infusing cubes of agar with a pH indicator, and then soaking the treated cubes in vinegar, you can model how diffusion occurs in cells. Then, by observing cubes of different sizes, you can discover why larger cells might need extra help to transport materials.
High School Chemistry
This set of a teacher and student guides provides instruction on a 2-3 day series of activities about Le Chateliers principle, which shows the effect of changes to conditions in an equilibrium reaction. Students work in pairs or groups to develop their concepts of equilibrium and the effects of changing the amount of reactants or products on an equilibrium system. The concepts are presented and analyzed using graphical representations, qualitative lab data, and modelling. The first part addresses the misconception that equal amounts are required for equilibrium through using a mini-activity that involves the transfer of water between beakers. The second part is a lab activity where students will see how an equilibrium system reacts to a change in concentration. The third part uses manipulatives to understand how an equilibrium operates using the mathematical equilibrium constant (Ksp) at the particulate view.
The purpose of this video lesson is to expand the student's knowledge about enzymes by introducing the antioxidant enzymes that are intimately involved in the prevention of cellular damage and eventual slowing of the aging process and prevention of several diseases. Students will learn that natural antioxidant enzymes are manufactured in the body and provide an important defense against free radicals. The topic of free radical action is introduced, covering how they are constantly generated in living cells both by ''accidents of chemistry'' and also by specific metabolic processes.
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. After the index cards have dried, they apply red cabbage juice as an indicator to reveal the designs.
Students learn the basics of acid/base chemistry in a fun, interactive way by studying instances of acid/base chemistry found in popular films such as Harry Potter and the Prisoner of Azkaban and National Treasure. Students learn what acids, bases and indicators are and how they can be used, including invisible ink. They also learn how engineers use acids and bases every day to better our quality of life. Students' interest is piqued by the use of popular culture in the classroom.
Students learn about various crystals, such as kidney stones, within the human body. They also learn about how crystals grow and ways to inhibit their growth. They also learn how researchers such as chemical engineers design drugs with the intent to inhibit crystal growth for medical treatment purposes and the factors they face when attempting to implement their designs. A day before presenting this lesson to students, conduct the associated activity, Rock Candy Your Body.
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 most flexible thermoset possible.
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). The activity culminates with student-designed experiments that utilize the constructed probes. The focus is to introduce students to the fabrication of the probe and expose them to two different ways to integrate the probe to obtain qualitative and quantitative measurements, while considering the application and utility of a conductivity probe within an engineering context. A provided handout guides teams through the process: background reading and questions; probe fabrication including soldering; probe testing and data gathering (including circuit creation on breadboard); probe connection to Arduino (including circuit creation and code entry) and a second round of testing and data gathering; design and conduct their own lab experiments that use the probes; online electrolyte/nonelectrolyte reading, short video, comprehension check and analysis questions.
In this demonstration, cook a cake using the heat produced when the cake batter conducts an electric current. Because of safety concerns, this activity should be conducted as a demonstration only and learners should be kept at a safe distance.
This video lesson aims to motivate students about chemistry and to raise their awareness about how chemistry helps in solving certain environmental problems. In this lesson, the air pollution problem created by cars and other vehicles is presented. The lesson will highlight causes of this problem, harmful products from it and possible solutions. There will also be discussion of ways to convert the pollutants produced by burning oil in vehicles into more friendly products.
Polymers are a vital part of our everyday lives and nearly all consumer products have a plastic component of some variation. Students explore the basic characteristics of polymers through the introduction of two polymer categories: thermoplastics and thermosets. During teacher demos, students observe the unique behaviors of thermoplastics. The fundamentals of thermoset polymers are discussed, preparing them to conduct the associated activity in which they create their own thermoset materials and mechanically test them. At the conclusion of this lesson-activity pair, students understand the basics of thermoplastics and thermosets, which may entice their interest in polymer engineering.
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 and one for sugar solutions. Finally, in section 3, students use the data they have analyzed to determine how to create a solution that has a particular boiling point and is a cost-effective design.
In this activity, learners conduct an oxidation experiment that turns old pennies bright and shiny. Learners soak 20 dull, dirty pennies in a bowl of salt and vinegar for five minutes. They rinse half the pennies with water, then compare the rinsed pennies to the unrinsed after all pennies sit and dry for about an hour. Learners also observe what happens when they submerge a screw and nail in the liquid compared to a nail only half-way submerged.
This 11-minute video lesson works through a calculation for K-Ar dating (it is good to have some prior experience with e and logarithms to understand). [Cosmology and Astronomy playlist: Lesson 80 of 85]
This 11-minute video lesson looks at Potassium-Argon (K-Ar) dating and it can be used to date very old volcanic rock and the things that might be buried in between. [Cosmology and Astronomy playlist: Lesson 79 of 85]
Concluding a two-part lab activity, students use triple balance beams and graduated cylinders to take measurements and calculate densities of several household liquids and compare them to the densities of irregularly shaped objects (as determined in Part 1). Then they create density columns with the three liquids and four solid items to test their calculations and predictions of the different densities. Once their density columns are complete, students determine the effect of adding detergent to the columns. After this activity, present the associated Density & Miscibility lesson for a discussion about why the column layers do not mix.
After students conduct the two associated activities, Density Column Lab - Parts 1 and 2, present this lesson to provide them with an understanding of why the density column's oil, water and syrup layers do not mix and how the concepts of density and miscibility relate to water chemistry and remediation. Topics covered include miscibility, immiscibility, hydrogen bonds, hydrophobic and hydrophilic. Through the density column lab activities, students see liquids and solids of different densities interact without an understanding of why the resulting layers do not mix. This lesson gives students insight on some of the most fundamental chemical properties of water and how it interacts with different molecules.
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 variations in the particle as well as in the fluid matrix. Students measure the ESR for each sample blood model, correlate the ESR values with disease conditions and confirm that diseases alter blood composition and properties. During the activity, students learn that when non-coagulated blood is let to stand in a tube, the red blood cells separate and fall to the bottom of the tube, resulting in a sediment and a clear liquid called serum. The height in millimeters of the clear liquid on top of the sediment in a time period of one hour is taken as the sedimentation rate. If a disease is present, this ESR value deviates from the normal, disease-free value. Different diseases cause different ESR values because blood composition and properties, such as density and viscosity, are altered differently by different diseases. Thus, the ESR test serves as a real-world diagnostic screening test to identify indications of the presence of any diseases in people.
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 can thus be separated by physical means.
The aim of this lesson is to introduce the concepts of Electrochemistry and Electroplating and to present their applications in our daily lives. Students are encouraged to construct their knowledge of Electroplating through brainstorming sessions, experiments and discussions. This video lesson presents a series of stories related to Electroplating and begins with a story about house gates as an example of the common items related to the Electroplating topic. Prerequisites for this lesson are knowledge of the basic concepts of electrolysis and chemical equations. The lesson will take about 60 minutes to complete, but you may want to divide the lesson into two classes if the activities require more time.
In this electrochemistry activity, learners will explore two examples of electroplating. In Part 1, zinc from a galvanized nail (an iron nail which has been coated with zinc by dipping it in molten zinc) will be plated onto a copper penny. In Part 2, copper from a penny will be plated onto a nickel.
This activity from the Exploratorium provides instructions to build an electroscope, a device that detects electrical charge. Common, inexpensive materials including film canisters, 3-M Scotch Magic™ Tape, and a plastic comb are used to show the attractions and repulsions between positively and negatively charged objects. The site also provides an explanation of the results and suggestions for extension activities.
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.
Under the "The Science Behind Harry Potter" theme, a succession of diverse complex scientific topics are presented to students through direct immersive interaction. Student interest is piqued by the incorporation of popular culture into the classroom via a series of interactive, hands-on Harry Potter/movie-themed lessons and activities. They learn about the basics of acid/base chemistry (invisible ink), genetics and trait prediction (parseltongue trait in families), and force and projectile motion (motion of the thrown remembrall). In each lesson and activity, students are also made aware of the engineering connections to these fields of scientific study.
Students explore the chemical identities of polymeric materials frequently used in their everyday lives. They learn how chemical composition affects the physical properties of the materials that they encounter and use frequently, as well as how cross-linking affects the properties of polymeric materials.
Students are challenged to think as biomedical engineers and brainstorm ways to administer medication to a patient who is unable to swallow. They learn about the advantages and disadvantages of current drug delivery methods—oral, injection, topical, inhalation and suppository—and pharmaceutical design considerations, including toxicity, efficacy, size, solubility/bioavailability and drug release duration. They apply their prior knowledge about human anatomy, the circulatory system, polymers, crystals and stoichiometry to real-world biomedical applications. A Microsoft® PowerPoint® presentation and worksheets are provided. This lesson prepares students for the associated activity in which they create and test large-size drug encapsulation prototypes to provide the desired delayed release and duration timing.
In this activity, learners explore liquid crystals, light and temperature. Using a postcard made of temperature-sensitive liquid crystal material, learners monitor temperature changes. By observing these changes, learners show that dark materials absorb and reemit the energy contained in light more readily than light-colored materials. Learners can also distinguish energy absorbed and reemited by radiation, convection, and conduction by comparing the behavior of black, white, and silver objects. This resource guide includes detailed explanation of the phenomenon and background information about liquid crystals.
This is an activity about a very important ingredient in most baked goods - gluten! Why is gluten so important? Without it, there would be nothing to hold the gas that makes bread rise. Learners will experiment with different types of flour to get a feel for gluten, and discover why using different flours can lead to such different results in the kitchen.
This activity provides students the opportunity to explore patterns in the periodic table. Students have options to display graphs of elements according to their atomic numbers and properties including: molar mass, atomic radius, ionic radius, melting point, boiling point, electronegativity, and ionization energies. Supplement Materials provided with the resource include a background essay and discussion questions. Discussion questions provided for the teacher encourage students to compare the properties of the elements and identify patterns in the properties within element families as well as across periods.
In this activity about chemistry and electricity, learners form a battery by placing their hands onto plates of different metals. Learners detect the current by reading a DC microammeter attached to the metal plates. Learners experiment with different metals to find out what combination produces the most current as well as testing what happens when they press harder on the plates or wet their hands. Learners also investigate what happens when they wire the plates to a voltmeter.
The unit “mole” is used in chemistry as a counting unit for measuring the amount of something. One mole of something has 6.02×1023 units of that thing. The magnitude of the number 6.02×1023 is challenging to imagine. The goal of this lesson is for students to understand just how many particles Avogadro's Number truly represents, or, how big is a mole. This lesson is meant for students currently enrolled in a first or second year chemistry course. This lesson is designed to be completed within one approximately 1 hour class; however, completion of optional activities 4 and 5 may require a longer class period or part of a second class period. This lesson requires only pencil and paper, as the activities suggested in this video place an emphasis on helping students develop their “back of the envelope” estimation skills. In fact, calculators and other measuring devices are explicitly discouraged. However, students may require additional supplies (poster board, colored pencils, markers, crayons, etc.) for the final optional/assessment activity, which involves creating a poster to demonstrate the size of a mole of their favorite macroscopic object.
In this classic hands-on activity, learners estimate the length of a molecule by floating a fatty acid (oleic acid) on water. This lab asks learners to record measurements and make calculations related to volume, diameter, area, and height. Learners also convert meters into nanometers. Includes teacher and student worksheets but lacks in depth procedure information. The author suggests educators search the web for more complete lab instructions.
This video is the second lesson in the How Cold Is Cold? BLOSSOMS series and examines the properties of materials under low temperature conditions. The video consists of a series of fascinating demonstrations with liquid nitrogen, which boils at 77K (-196 C -321 F). These demonstrations include the following: What goes up, may not come down; Is that supposed to be cold? - thermal insulation; Some properties of liquid nitrogen; Making ice cream - the slow way and the fast way; Try not to explode: expansion of liquid nitrogen and the ideal gas law; Making the air cold: phase changes and the affect on volume; No frozen fingers: the changes in mechanical properties; Resistivity at 77K; The magic magnet: the Meissner Effect; Cautions in using liquid nitrogen
This lab exercise exposes students to a potentially new alternative energy source hydrogen gas. Student teams are given a hydrogen generator and an oxygen generator. They balance the chemical equation for the combustion of hydrogen gas in the presence of oxygen. Then they analyze what the equation really means. Two hypotheses are given, based on what one might predict upon analyzing the chemical equation. Once students have thought about the process, they are walked through the experiment and shown how to collect the gas in different ratios. By trial and error, students determine the ideal combustion ratio. For both volume of explosion and kick generated by explosion, they qualitatively record results on a 0-4 scale. Then, students evaluate their collected results to see if the hypotheses were correct and how their results match the theoretical equation. Students learn that while hydrogen will most commonly be used for fuel cells (no combustion situation), it has been used in rocket engines (for which a tremendous combustion occurs).
In this activity, learners investigate the speed of chemical reactions with light sticks. Learners discover that reactions can be sped up or slowed down due to temperature changes.
Students learn about material balances, a fundamental concept of chemical engineering. They use stoichiometry to predict the mass of carbon dioxide that escapes after reacting measured quantities of sodium bicarbonate with dilute acetic acid. Students then produce the reactions of the chemicals in a small reactor made from a plastic water bottle and balloon.
Through two lessons and five activities, students explore the structure and function of cell membranes. Specific transport functions, including active and passive transport, are presented. In the legacy cycle tradition, students are motivated with a Grand Challenge question. As they study the ingress and egress of particles through membranes, students learn about quantum dots and biotechnology through the concept of intracellular engineering.
Students learn how crystallization and inhibition occur by examining calcium oxalate crystals with and without inhibitors that are capable of altering crystallization. Kidney stones are composed of calcium oxalate crystals, and engineers and doctors experiment with these crystals to determine how growth is affected when a potential drug is introduced. Students play the role of engineers by trying to determine which inhibitor would be the best for blocking crystallization.