Energy balances that include entropy consist of two parts: A balance that accounts for the changed entropy content of the substances, and another one that accounts for the energy freed or taken by that reaction itself, the Gibbs energy change. The sum of reaction energy and energy associated to the change of entropy content is also called enthalpy. Often the whole enthalpy is carried by entropy and thus measurable calorimetrically. For standard conditions in chemical reactions either molar entropy content and molar Gibbs energy with respect to some chosen zero point are tabulated. Or molar entropy content and molar enthalpy with respect to some chosen zero are tabulated. (See Standard enthalpy change of formation and Standard molar entropy) The substance potential of a redox reaction is usually determined electrochemically current-free using reversible cells. Redox electrode Other values may be determined indirectly by calorimetry. Also by analyzing phase-diagrams. Sub-microstructural properties of condensed matter, gas Infrared spectroscopy Neutron detector Radio frequency spectrometers for nuclear magnetic resonance and electron paramagnetic resonance Raman spectroscopy Crystal structure An X-ray tube, a sample scattering the X-rays and a photographic plate to detect them. This constellation forms the scattering instrument used by X-ray crystallography for investigating crystal structures of samples. Amorphous solids lack a distinct pattern and are identifiable thereby. Imaging technology, microscope Electron microscope Scanning electron microscope Transmission electron microscope Optical microscope uses reflectiveness or refractiveness of light to produce an image. Scanning acoustic microscope Scanning probe microscope Atomic force microscope (AFM) Scanning tunneling microscope (STM) Focus variation X-ray microscope (See also Spectroscopy and List of materials analysis methods.) Rays ("waves" and "particles") Sound, compression waves in matter Microphones in general, sometimes their sensitivity is increased by the reflection- and concentration principle realized in acoustic mirrors. Laser microphone Seismometer Sound pressure Microphone or hydrophone properly gauged Shock tube Sound level meter Light and radiation without a rest mass, non-ionizing Antenna (radio) Bolometer measuring the energy of incident electromagnetic radiation. Camera EMF meter Interferometer used in the wide field of interferometry Microwave power meter Optical power meter Photographic plate Photomultiplier Phototube Radio telescope Spectrometer T-ray detectors (for lux meter, see the section about human senses and human body) See also :Category:Optical devices Photon polarization Polarizer Pressure (current density of linear momentum) Nichols radiometer Radiant flux The measure of the total power of light emitted. Integrating sphere for measuring the total radiant flux of a light source Radiation