Paul Andersen discusses the technology, advantages and disadvantages of six sources of renewable energy; biomass, hydroelectric, solar, geothermal wind, and hydrogen. He also explains how changes in the storage and flow of energy in our power grid must be improved. [9:21]

Paul Andersen explains how the resistivity of a material opposes the flow of charge. [4:22]

The following video narrated by Paul Andersen explains how resistors and capacitors affect circuits. The resistance of a resistor is affected by the resistivity of the material and the geometry of the resistor. The current through a resistor can be determined by Ohm's Law. [9:16]

Paul Andersen starts this video with a description of the respiratory surface. He explains how worms, insects, fish, and mammals take in oxygen and release carbon dioxide. He then tours the major organs of the respiratory system; from the pharynx to the trachea, bronchus, bronchiole and alveoli. A video review worksheet is also provided. [8:45]

Physics video [10:40] from science teacher, Paul Andersen, in which he teaches us the concept of rotational force through images and formulas using clear and understandable explanations.

Paul Andersen describes the important features of the skeletal system. He starts by comparing and contrasting endoskeletons and exoskeletons. He then explains how the human skeleton provides support, movement, storage, blood production, and homeostasis. [7:58]

Paul Andersen explains how soils are formed and classified. Weathering of rock creates particles which are mixed with water, air, and organic material. Soils are classified according to particle size, chemical makeup, and horizon distribution. [9:22]

In the following video Paul Andersen explains how the dissolution of a solute in a solution can be explained as a reversible reaction. Bonds in the solid solute are broken and the ions are dissolved in a solution. The Ksp (or solubility product constant) can be used to explain the solubility of various salts. [7:06]

In the following video Paul Andersen explains how light that is perfectly reflected creates specular reflection. The angle of the incident ray is equal to the angle of the reflected ray. Specular reflection is also known as mirror-like reflection. If the reflecting surface is irregular it will create diffuse, rather than specular reflection. [4:33]

In this video Paul Andersen explains how the boundary between the system and environment is chosen to simplify analysis of a physics problem. [3:13]

The following video narrated by Paul Andersen explains how systems are two or more objects that interact with one another. If a system has no relevant internal structure it can be treated as an object. The conservation laws apply to energy, charge and momentum in a system. [2:29]

In the following video Paul Andersen explains how objects in contact with varying temperatures will eventually reach thermal equilibrium with equal temperatures. The amount of thermal energy transferred is related to the mass and temperature of the objects since momentum is transferred and conserved along the margin. [3:48]

In the following video Paul Andersen explains how the total energy of a system is the combination of kinetic, potential and internal energy of the objects. He then shows you how to calculate the kinetic energy, gravitational potential energy, and elastic potential energy of objects within a system. Over time the total energy of the system will change due to changes in position and frictional effects. [6:14]

Paul Andersen explains how a vector field shows the distribution of vector quantities. [7:47]

Paul Andersen explains how the vector sum of forces can be used to identify the net force on an object. The net force can be used to determine the overall acceleration of the object using Newton's Second Law. [6:54]

Paul Andersen explains how water quality can be degraded by pollutants. Wastewater is the main source of water pollution and can be measured using the BOD (biochemical oxygen demand). Dead zones, cultural eutrophication, disease, and other pollutants are included. A 'Water Pollution Concept Map' is also available for download. [9:07]

Paul Andersen explains how water is unequally distributed around the globe through the hydrologic cycles. Seawater is everywhere but is not useful without costly desalination. Freshwater is divided between surface water and groundwater but must me stored and moved for domestic, industrial, and agricultural uses. [11:38]

Paul Andersen explains how the energy of a wave if directly related to the amplitude of a wave. The wave energy of a sound wave is the volume of the wave. [3:39]

In the following video the wave model of the electron can be used to explain the Bohr model. Electrons are found in certain orbits because they interfere with themselves and create standing waves. When the wavelengths don't match up with a whole integer they will create destructive interference. [4:02]