Browse by Grade & Topic: Atoms, molecules, and chemical bonds

Use protons, neutrons, and electrons to build elements. As the number of protons, neutrons, and electrons changes, information such as the name and symbol of the element, the Z, N, and A...

Explore what isotopes are by adding protons and neutrons to the nucleus of an atom. Plot both stable and radioactive isotopes on a graph of neutrons vs. protons, and explore how the...

The atomic mass for each element listed in the periodic table is actually the weighted average mass of all of the different isotopes of the element. In the Average Atomic Mass Gizmo, use a...

Simulate ionic bonds between a variety of metals and nonmetals. Select a metal and a nonmetal atom, and transfer electrons from one to the other. Observe the effect of gaining and losing...

Choose a substance, and then move electrons between atoms to form covalent bonds and build molecules. Observe the orbits of shared electrons in single, double, and triple covalent bonds....

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Investigate the decay of a radioactive substance. The half-life and the number of radioactive atoms can be adjusted, and theoretical or random decay can be observed. Data can be interpreted...

Every substance has unique transition points, or temperatures at which one phase (solid, liquid, or gas) transitions to another. Use a realistic melting point apparatus to measure the...

Have you ever used a glove warmer to keep your hands warm? How about an instant cold pack to treat an injury? In the Feel the Heat Gizmo, create your own hot and cold packs using various...

Understand the definition of a mole and determine the Avogadro constant by adding atoms or formula units to a balance until the mass in grams is equal to the atomic or formula mass....

Learn about molecular polarity and how polarity gives rise to intermolecular forces. Measure four macroscopic properties of liquids (cohesion, adhesion, surface tension, and capillary...

The Secret Service recently arrested suspects accused of counterfeiting coins from 1915 valued at $50,000 each. The students act as a forensic scientist to investigate the crime scene and...