This is the first of three linked web pages. The one listed introduces the concept of mass and the question of how it may be measured without recourse to gravity, e.g. in the weightless environment of a space station. The second tells how such measurements were actually conducted in 1973 aboard “Skylab,” and the third describes a simple experiment of comparing masses without using gravity, requiring only a hacksaw blade, clamps, bolts and a watch.
This site is an article that discusses, in depth, what dark matter is. The material is taken from current literature that looks at how scientists have determined the mass discrepancy, what they think dark matter is and how they are looking for it, and how dark matter fits into current theories about the origin and fate of the universe.
This article from the Australian Telescope National Facility describes the death of massive stars. It discusses the formation and characteristics of supernovae, hypernovae, neutron stars/pulsars, and black holes. The article includes an animated diagram showing how the pulsar beam is observed from Earth.
Using an image taken by the Large Angle and Spectrometric Coronagraph (LASCO) instrument on board the Solar and Heliospheric Observatory (SOHO) spacecraft, along with the National Institutes of Health (NIH) Image program for image processing, students investigate the acceleration of a coronal mass ejection (CME) into space. They will find the velocity and acceleration of a CME and whether it accelerates uniformly away from the Sun.
This web page from the Exploratorium museum helps students understand the difference between mass and weight. Enter an “Earth weight”, and the site automatically calculates your weight on the moon, other planets, and three stars. It also includes background information on the relationship between gravity, mass, and distance.
This simulation promotes understanding of isotopes by providing a simple way to model isotopes of the first 10 elements in the Periodic Table. In the most basic model, users click on an atomic symbol. The simulation displays a stable isotope for that atom. (For example, choose Helium and view a nucleus with two protons and two neutrons.) Now, drag neutrons into the nucleus and watch to see if atom becomes unstable. Students may be surprised to see that Beryllium and Flourine, for example, are unstable with equal numbers of protons and neutrons in the nucleus.
FIGURE 2. Rab family small GTP-binding proteins identified in AQP2-vesicles from inner medullary collecting duct. Rab GTPases and their effectors coordinate vesicle transport. They are involved in vesicle budding, transport, docking, and fusion. All Rab proteins listed were identified in the AQP2-containing vesicles except Rab3. CCV, clathrin-coated vesicle; EE, early endosome; ER, endoplasmic reticulum; LE, late endosome; RE, recycling endosome. Trairak Pisitkun, Jason D. Hoffert, Ming-Jiun Yu, and Mark A. Knepper. Tandem Mass Spectrometry in Physiology. Physiology 22: 390-400, 2007