concentration

Examples of concentration in the following topics:

• Diffusion

  • Diffusion is the movement of particles from regions of high concentration towards regions of lower concentration.
  • Diffusion is the movement of particles move from an area of high concentration to an area of low concentration until equilibrium is reached .
  • Diffusion explains the net flux of molecules from a region of higher concentration to one of lower concentration.
  • However, diffusion can still occur in the absence of a concentration gradient.
  • Particles moving from areas of high concentration to areas of low concentration.

• Electric Potential in Human

  • As a result, a cell can contain a concentration of a given ion that differs from that which exists outside.
  • No energy is required for this to occur, and therefore ions can only move from areas of higher concentration to those of lower concentration.
  • This involves ion pumps using energy to push an ion from an area of lower concentration to one of higher concentration.
  • This impulse is passed through the axon, a long extension of the cell, in the form of an electrical potential created by differing concentrations of sodium and potassium ions on either side of a membrane in the axon .
  • This impulse is passed through the axon, a long extension of the cell, in the form of an electrical potential created by differing concentrations of sodium and potassium ions on either side of a membrane in the axon.

• Molecular Transport Phenomena

  • The rate of diffusion is proportional to the concentration difference.
  • Many more molecules will leave a region of high concentration than will enter it from a region of low concentration.
  • Osmosis is driven by the imbalance in water concentration.
  • For example, water is more concentrated in your body than in Epsom salt.
  • Osmosis will be to the right, since water is less concentrated there.

• Newton's Rings

  • Newton's rings are a series of concentric circles centered at the point of contact between a spherical and a flat surface.
  • Newton's rings appear as a series of concentric circles centered at the point of contact between the spherical and flat surfaces.
  • When viewed with monochromatic light, Newton's rings appear as alternating bright and dark rings; when viewed with white light, a concentric ring pattern of rainbow colors is observed.

• The Rutherford Model

  • Rutherford confirmed that the atom had a concentrated center of positive charge and relatively large mass.
  • Rutherford's new model for the atom, based on the experimental results, contained the new features of a relatively high central charge concentrated into a very small volume in comparison to the rest of the atom.
  • Bottom: Observed results -- a small portion of the particles were deflected, indicating a small, concentrated positive charge.

• Gravitational Attraction of Spherical Bodies: A Uniform Sphere

  • The Shell Theorem states that a spherically symmetric object affects other objects as if all of its mass were concentrated at its center.
  • A spherically symmetric object affects other objects gravitationally as if all of its mass were concentrated at its center,
  • Given that a sphere can be thought of as a collection of infinitesimally thin, concentric, spherical shells (like the layers of an onion), then it can be shown that a corollary of the Shell Theorem is that the force exerted in an object inside of a solid sphere is only dependent on the mass of the sphere inside of the radius at which the object is.
  • The net gravitational force that a spherical shell of mass $M$ exerts on a body outside of it, is the vector sum of the gravitational forces acted by each part of the shell on the outside object, which add up to a net force acting as if mass $M$ is concentrated on a point at the center of the sphere (Statement 1 of Shell Theorem).
  • The resulting net gravitational force acts as if mass $M$ is concentrated on a point at the center of the sphere, which is the center of mass, or COM (Statement 1 of Shell Theorem).

• Nerve Conduction and Electrocardiograms

  • This membrane separates electrically neutral fluids having differing concentrations of ions, the most important varieties being Na+, K+, and Cl− (these are sodium, potassium, and chlorine ions).
  • Free ions will diffuse from a region of high concentration to one of low concentration.
  • Only small fractions of the ions move, so that the cell can fire many hundreds of times without depleting the excess concentrations of Na+ and K+.
  • The semipermeable membrane of a cell has different concentrations of ions inside and out.

• Conductors and Fields in Static Equilibrium

  • It should be noted that the distribution of charges depends on the shape of the conductor and that static equilibrium may not necessarily involve an even distribution of charges, which tend to aggregate in higher concentrations around sharp points.
  • This explains the difference in concentration of charge on flat vs. pointed areas of a conductor.

• Biological and Medical Applications

  • Another important form of fluid movement is osmosis—the transport of water through a semipermeable membrane (shown in ) from a region of high concentration to a region of low concentration.
  • It is driven by the imbalance in water concentration.
  • Similarly, dialysis is the transport of any other molecule through a semipermeable membrane due to its concentration difference.

• Problems

  • Using the results depicted in Figure 10.4, estimate the temperature of the hot and cold car exhaust and the relative concentration of CO in the two cases.