water potential

Examples of water potential in the following topics:

• Water and Solute Potential

  • Water potential is the measure of potential energy in water and drives the movement of water through plants.
  • Water potential is critical for moving water to leaves so that photosynthesis can take place.
  • Water potential is a measure of the potential energy in water, or the difference in potential energy between a given water sample and pure water (at atmospheric pressure and ambient temperature).
  • When this happens, water moves to equilibrate, moving from the system or compartment with a higher water potential to the system or compartment with a lower water potential.
  • Solutes reduce water potential (resulting in a negative Ψw) by consuming some of the potential energy available in the water.

• Pressure, Gravity, and Matric Potential

  • Water potential is affected by factors such as pressure, gravity, and matric potentials.
  • This increases water potential between the water in the the petiole (base of the leaf) and in the leaf, thereby encouraging water to flow from the petiole into the leaf.
  • The force of gravity pulls water downwards to the soil, which reduces the total amount of potential energy in the water in the plant (Ψtotal).
  • The binding of water to a matrix always removes or consumes potential energy from the system.
  • When (a) total water potential (Ψtotal) is lower outside the cells than inside, water moves out of the cells and the plant wilts.

• Movement of Water and Minerals in the Xylem

  • Transpiration aids in the movement of water and minerals in the xylem, but it must be controlled in order to prevent water loss.
  • It is the main driver of water movement in the xylem.
  • Water from the roots is pulled up by this tension.
  • The energy driving transpiration is the difference in energy between the water in the soil and the water in the atmosphere.
  • Evaporation from the mesophyll cells produces a negative water potential gradient that causes water to move upwards from the roots through the xylem.

• Types of Energy

  • The various types of energy include kinetic, potential, and chemical energy.
  • Other examples of potential energy include the energy of water held behind a dam or a person about to skydive out of an airplane.
  • This type of potential energy is called chemical energy, and like all potential energy, it can be used to do work.
  • Water behind a dam has potential energy.
  • Moving water, such as in a waterfall or a rapidly flowing river, has kinetic energy.

• How a business can save water

  • Saving water is always worth the effort.
  • Faced with regional droughts and potential water use restrictions, the company decided to act fast and expects to save $60 million annually.
  • It's everyone's job to save water so make it everyone's job to save water.
  • Recycle ‘grey water' and rainwater.
  • Most industrial systems use tap water (e.g. drinking water) for most, if not all, of their production needs.

• Gravity

  • The potential energy due to elevated positions is called gravitational potential energy, evidenced, for example, by water held in an elevated reservoir or behind a dam (as an example, shows Hoover Dam).
  • (The surface will be the zero point of the potential energy. ) We can express the potential energy (gravitational potential energy) as:
  • For this choice, the potential at infinity is defined as 0.
  • Hoover dam uses the stored gravitational potential energy to generate electricity.
  • Generate an equation that can be used to express the gravitational potential energy near the earth

• The Degradation of Synthetic Chemicals in Soils and Water

  • Microorganisms are crucial participants in the detoxification of water and soil.
  • These pollutants can cause dangerous contamination of the air, soil, and water.
  • They also have the potential to clean the water from toxic components.
  • The final products are water, carbon dioxide, and methane.
  • In recent years, advances in genomics, proteomics, and bioinformatics studies of environmental microorganisms have revealed a tremendous potential in metabolic pathways.

• Equilibrium Constant and Cell Potential

  • If possible, a species will move from areas with higher electrochemical potential to areas with lower electrochemical potential.
  • For example, if a glass of water has sodium ions (Na+) dissolved uniformly in it, and an electric field is applied across the water, then the sodium ions will tend to get pulled by the electric field toward one side.
  • We say the ions have electric potential energy, and are moving to lower their potential energy.
  • Likewise, if a glass of water has a lot of dissolved sugar on one side and none on the other side, each sugar molecule will randomly diffuse around the water until there is and equal concentration of sugar everywhere.
  • These two examples show that an electrical potential and a chemical potential can both give the same result: a redistribution of the chemical species.

• How businesses waste water

  • The amount of water in the world is finite, yet between 1900 and 1995 global water consumption rose sixfold – more than double the rate of population growth.
  • (BBC, news.bbc.co.uk/2/hi/science/nature/3747724.stm) Interestingly, although our planet is mostly covered by water, more than 97% of it contains salt, making it unsuitable for drinking or irrigation (desalinating salt water produces one-third potable water and two-thirds poisonous, intensely salted waste that cannot be reintroduced into the environment without repercussions).
  • Less than half of one per cent can be used by humans, but this amount increasingly poses a potential hazard because it's rapidly becoming more polluted.
  • Currently, around 50% of the world's diseases are caused by contaminated water, and water rights have been – and continue to be – a worldwide source of conflict because water shortages often translate into food shortages and manufacturing difficulties.
  • The bottom line is that minimizing water consumption in business not only lowers operating costs, reduces water disposal expenses and promotes regional, national and international stability,it's also the right thing to do.

• Electric Potential in Human

  • Electric potentials are commonly found in the body, across cell membranes and in the firing of neurons.
  • Electric potentials are not limited in function to inorganic processes.
  • Cell membranes are only semipermeable; water can freely travel in and out, but ions can be selectively admitted passage across them.
  • Thus, a potential, called the resting potential, is created on either side of the membrane.
  • Potentials can change as ions move across the cell membrane.