In this interactive activity from ChemThink, take a closer look at atomic structure, properties, and behaviors.

This video segment adapted from A Science Odyssey takes a look at the scale of the atom and the tremendous amount of space between the electrons and the nucleus. If all this empty space exists in matter, how can any substance be solid?

Starting from atoms, see how many molecules you can build. Collect your molecules and see them in 3D!

There are two types of catalysis reactions: homogeneous and heterogeneous. In a homogeneous reaction, the catalyst is in the same phase as the reactants. In a heterogeneous reaction, the catalyst is in a different phase from the reactants. This activity addresses homogeneous catalysis.

This interactive activity helps learners visualize the role of electrons in the formation of ionic and covalent chemical bonds. Students explore different types of chemical bonds by first viewing a single hydrogen atom in an electric field model. Next, students use sliders to change the electronegativity between two atoms -- a model to help them understand why some atoms are attracted. Finally, students experiment in making their own models: non-polar covalent, polar covalent, and ionic bonds. This item is part of the Concord Consortium, a nonprofit research and development organization dedicated to transforming education through technology.

In this interactive activity, learners explore factors that cause atoms to form (or break) bonds with each other. The first simulation depicts a box containing 12 identical atoms. Using a slider to add heat, students can see the influence of temperature on formation of diatomic bonds. Simulations #2 and #3 introduce learners to reactions involving two types of atoms. Which atom forms a diatomic molecule more easily, and why? The activity concludes as students explore paired atoms (molecules). In this simulation they compare the amount of energy needed to break the molecular bonds to the energy needed to form the bonds. This item is part of the Concord Consortium, a nonprofit research and development organization dedicated to transforming education through technology.

This video from NASA features the Cosmic Origin Spectrograph (COS), which allows scientists to use spectrographic analysis to assess the composition of intergalactic material.

This interactive activity from ChemThink takes a closer look at a covalent bond--how it is formed and how the sharing of two electrons can keep atoms together.

This activity introduces the role of diffusion in supplying cells with nutrients and removing wastes.

This video segment adapted from A Science Odyssey looks at the invention of nylon.

Intermolecular attractions are responsible for everything from the temperatures at which substances boil to the power of your immune system in recognizing pathogens and the climbing ability of geckos! Feel the strength of London dispersion and dipole-dipole attractions, explore how intermolecular attractions affect boiling point and solubility, and investigate the special role of hydrogen bonds in DNA. Finally, design your own antibody based on intermolecular attractions.

In this interactive activity from ChemThink, learn how ionic bonds are formed and how an ionic bond structure is represented by its formula.

This video segment adapted from Discovering Women profiles Fermilab physicist and Harvard professor Melissa Franklin.

In this activity, students interact with 12 models to observe emergent phenomena as molecules assemble themselves. Investigate the factors that are important to self-assembly, including shape and polarity. Try to assemble a monolayer by "pushing" the molecules to the substrate (it's not easy!). Rotate complex molecules to view their structure. Finally, create your own nanostructures by selecting molecules, adding charges to them, and observing the results of self-assembly.

In this interactive activity from ChemThink, learn about covalent molecules and how the VSEPR theory predicts the shapes of covalently-bonded molecules.

In this video adapted from NOVA scienceNOW, find out about the discovery of a new building material, the carbon nanotube, whose physical properties could theoretically enable the creation of a 22,000-mile elevator to space.

In this interactive activity from ChemThink, examine the basic properties of matter at an atomic level and consider how various atoms affect the way a substance behaves.

This interactive periodic table developed for Teachers' Domain provides detailed information about the chemical properties of elements and illustrates the electron configurations that determine those characteristics.

This animation adapted from Garland Science Publishing takes a close look at the DNA double helix and its individual components, describing their chemical structures and how they function together to make the DNA molecule unique.

This animation produced by WGBH and Digizyme, Inc. demonstrates the experimental technique used to introduce DNA plasmids inside bacterial cells, a process called bacterial transformation.