Collisional Heating by CO2 in the Atmosphere:
This applet illustrates the absorption of infrared radiation by CO2 in the troposphere and the collisional loss of this absorbed energy to surrounding N2 and O2 molecules. In this applet the user can sweep through a region of the IR-spectrum and excite some of the vibratory modes of CO2. A simple (purely qualitative) thermometer illustrates the rise in temperature of the gas as collisional de-excitation occurs.
The behaviour of CFC's is dependent on both the wavelength of radiation as well as position of the molecule in the atmosphere. In this applet the user can investigate the various interaction modes of a CFC molecule with electromagnetic radiation across the entire spectrum. The molecule can be rotated in 3D to better view the vibration induced by interaction with light.
Structure of the Atmosphere
Understanding the structure of the atmosphere is critical to being able to understand where and how global warming of the atmosphere occurs. This applet illustrates the major layers in the atmosphere and identifies a number of key characteristics and defining attributes of each layer.
Functional Groups, IR spectra, and Molecular Vibrations
Many organic molecules exhibit characteristic vibrational modes that produce spectral features in the infrared region. These provide the experimental basis for identifying functional groups. This digital learning object introduces the major functional groups, and interprets their infrared spectra with animated molecular models showing some of the more important vibrational modes used to identify them. Please be patient - this is a very large applet and will take a few seconds to download.
Infrared Spectral Windows
Greenhouse gases produce spectral features in the infrared portion of the spectrum. One area of concern is the rapidly closing "IR-window" - a phenomenon which occurs because different greenhouse gases absorb in different parts of the IR window. This has potentially serious consequences for global warming. The applet on the right shows how the IR signatures of a number of greenhouse gases collectively "close" the window.
The importance of isotopes is evident in the many applications of isotope ratio mass spectrometry. In this series, four applications are introduced through interactive lessons. Please be patient - this is a large applet and download will take a few moments.
13C Nuclear Magnetic Resonance Spectroscopy
13C NMR spectroscopy is a powerful tool to help determine the structure of molecules in organic chemistry, by mapping the framework of C atoms in a molecule. In the applet, NMR spectra are correlated with a rotatable 3D molecular structure, showing how to connect the resonances, or peaks, in a spectrum with the sets of C atoms that are in unique environments in a molecule.
1H Nuclear Magnetic Resonance Spectroscopy
1H NMR spectroscopy is a complementary tool to 13C NMR spectroscopy to help determine the structure of molecules in organic chemistry, by mapping the connectivity of H atoms in a molecule. In the applet, NMR spectra are correlated with a rotatable 3D molecular structure, showing how to connect the resonances, or peaks, in a spectrum with the sets of H atoms that are in unique environments in a molecule.
Seeing molecules in 3D greatly enhances the student's ability to understand chirality and how conformation influences chemical behaviour.
The Stereo Molecule Viewer Project, Molecules are drawn in a 3d environment, can be projected in 3d using a geowall. The applet can also rotate, zoom, translate, and measure many parts of the molecule. It can import pdb, mol and mol2 files, exportable from many chemistry programs, and found on the web.
Atomic Weight Calculator
This applet is used to explore the relationship between the isotopic ratios of an element and the element's atomic weight. Select any atomic element and manipulate its isotope ratios using the provided pie chart or table. A formula for atomic weight is dynamically created based on the given input.