In this video segment adapted from ZOOM, two cast members demonstrate what happens when vinegar is added to baking soda inside a container. The resulting chemical reaction produces enough carbon dioxide to launch their paper rocket skyward.
Recommended for: Grades K-5

Watch this video lesson introducing the atom, and learn about its unique structure. [3:58]

Biology 2e is designed to cover the scope and sequence requirements of a typical two-semester biology course for science majors. The text provides comprehensive coverage of foundational research and core biology concepts through an evolutionary lens. Biology includes rich features that engage students in scientific inquiry, highlight careers in the biological sciences, and offer everyday applications. The book also includes various types of practice and homework questions that help students understand—and apply—key concepts. The 2nd edition has been revised to incorporate clearer, more current, and more dynamic explanations, while maintaining the same organization as the first edition. Art and illustrations have been substantially improved, and the textbook features additional assessments and related resources.

By the end of this section, you will be able to do the following:

Define matter and elements
Describe the interrelationship between protons, neutrons, and electrons
Compare the ways in which electrons can be donated or shared between atoms
Explain the ways in which naturally occurring elements combine to create molecules, cells, tissues, organ systems, and organisms

Paul Andersen shows you how to write balanced equations that describe chemical changes. He then gives you a short introduction to balancing equations and uses the PHET site to practice this skill. [9:39]

This site provides a detailed overview of atoms. Content explores an atom's structure, as well as what ions are, how atoms bond, what compounds are (including how to name compounds), and what isotopes are.

Why do atoms react with some elements but not others, and why do they form compounds with such different properties? One of the reasons is the bonds that they form. This pathway provides resources relating to the reasons that atoms bond, and the three different types of bonds that form between atoms: covalent, ionic and metallic.

Covers ionic radius, determination of ionic radius, and trends in ionic radii.

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The interactions of electrons with matter have great explanatory power and are central to many technologies from transistors, diodes, smoke detectors, and dosemeters to sophisticated imaging, lasers, and quantum computing. A conceptual grasp of the interactions of electrons in general allows students to acquire deeper understanding that can be applied to a very broad range of technologies.

Students learn about current electricity and necessary conditions for the existence of an electric current. Students construct a simple electric circuit and a galvanic cell to help them understand voltage, current and resistance.

Students use gumdrops and toothpicks to make lithium atom models. Using these models, they investigate the makeup of atoms, including their relative size. Students are then asked to form molecules out of atoms, much in the same way they constructed atoms out of the particles that atoms are made of. Students also practice adding and subtracting electrons from an atom and determining the overall charges on atoms.

Why are some substances liquids, while others are solids? Why are some substances harder than others? Why is water essential for life on Earth? This pathway provides resources for answering these questions by looking at the types of intermolecular foces that exist between particles, and the effect that these forces have on the macroscopic properties of substances.

Students act as engineers to apply what they know about how circuits work in electrical/motorized devices to design their own battery-operated model motor vehicles with specific paramaters. They calculate the work done by the vehicles and the power produced by their motor systems.

Students perform one of the first steps that environmental engineers do to determine water quality sampling and analysis. Student teams measure the electrical conductivity of four water samples (deionized water, purified water, school tap water and a salt-water solution) using teacher-made LED-conductivity testers and commercially available electrical conductivity meters. They use multimeters to also measure the resistance of the samples. They graph their collected data to see the relationship between the conductivity and resistance. Then, all students measure the conductivity of tap water samples brought to school from their homes; they organize and average their data by sub areas within their local school district to see if house location has any relationship to the water conductivity in their community.

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 as classroom-prepared acidic water, hard water and seawater using four tests: a “shake test” (assessing the amount of bubbles produced), a surface tension test, a viscosity test, and a pH test. Then they coalesce their findings into a recommendation for how to engineer the best soap versus shampoo. The activity may be shortened by using purchased liquid soap and shampoo from which students proceed to conduct the four tests. A lab worksheet and post-quiz are provided.

A narrated screencast which illustrates the solubility rules of common ions. This lesson provides examples on how to determine if an ionic compound will dissociate in water. [5:17]

Students come to understand static electricity by learning about the nature of electric charge, and different methods for charging objects. In a hands-on activity, students induce an electrical charge on various objects, and experiment with electrical repulsion and attraction.

Through a series of video lectures and some review questions, learn about the Bohr model of the atom and the periodic table of elements. [7:51]