In this video Paul Andersen explains how the reaction path can be described in an energy profile. Enough energy must be added to reach the activation energy required and stress the bonds. Eventually the bonds break and new bonds are...

In this video Paul Andersen explains how classical waves (like light) can have particle properties. Albert Einsetein used the photoelectric effect to show how photons have particle properties.

Paul Andersen attempts to explain Gibbs Free Energy. He begins by using three spontaneous reactions to explain how a change in enthalpy, entropy and temperature can affect the free energy of a system. He then applies this concept to...

Paul Andersen explains how biogeochemical cycling is used to move nutrients from the environment into living material and back again. He explains the water cycle, the carbon cycle, the nitrogen cycle and the phosphorus cycle. He also...

In this video Paul Andersen explains how the average value of the electric field can be determined by dividing the potential difference by the displacement. Equipotential lines can be used to determine the potential in an electric field...

In this video Paul Andersen explains how the wave speed measure the speed of a wave through a medium. The medium determines the speed of the wave. The velocity of the wave is equal to the product of the wavelength and the frequency of...

In this video Paul Andersen explains how the energy, charge, and momentum in a system is conserved over time.

Paul Andersen starts with a brief description of feeding methods. He then details all of the major parts within the human digestive system. This tour starts in the mouth, move down the esophagus, through the stomach, small investing,...

In this video Paul Andersen gives an overview of the human urinary system. The system consist of the kidneys, ureters, bladder, and urethra. The kidneys excrete waste from the blood in urine. He explains how the nephron is responsible...

A mini-lesson on observational patterns.

In this video Paul Andersen describes how reversible reactions achieve equilibrium as reactants are converted to products and products are converted to reactants. A model shows how forward reaction rates and reverse reactions rates...

In this video Paul Andersen explains how a rotating system will have several quantities; including torque, angular velocity, angular acceleration and angular momentum. Each of these quantities have a vector property that can be...

In this video Paul Andersen explains how the angular momentum of a system can be calculated by determining the angular momentum of all individual objects within the system. An inquiry activity using a gyroscope is also included.

In this podcast Paul Andersen explains how cells differentiate to become tissue specific. He also explains the role of transcription factors in gene regulation. The location of a cell within the blastula ultimately determines its fate....

In this video Paul Andersen explains how buffer solutions maintain pH in a solution. A buffer solution is made up of a weak acid and its conjugate base. As strong acids or bases are added the pH remains stable. A good buffer solution has...

In this video Paul Andersen explains how the magnetic permeability is the ability of a material to form internal magnetic fields. The magnetic permeability of free space is a constant and is much lower than the magnetic permeability of...

Paul Andersen explains how populations eventually reach a carrying capacity in logistic growth. He begins with a brief discussion of population size ( N ), growth rate ( r ) and exponential growth. He then explains how density dependent...

In this video Paul Andersen explains how the electric field strength decreases as the square of the radius as you move away from a point charge, or a uniform distribution of charge on a sphere. This is a direct application of Coulomb's Law.

In this video Paul Andersen explains how forces on an object always require another object. An object cannot exert a force on itself. If net forces on an object are balanced the object will remain at rest or move with a constant...

In this video Paul Andersen explains how ionic solids form a lattice between cations and anions. According the Coulomb's Law the lattice energy increases as the ions carry a larger charge and are smaller. Some of the properties of ionic...

Paul Andersen explains the importance and structure of nucleic acids. He begins with an introduction to DNA and RNA. He then describes the important parts of a nucleotide and shows how they are connected through covalent and hydrogen...

In this video Paul Andersen explains how heating is the transfer of energy (heat) from a warmer object to a cooler object. Heat can be transferred through conduction, convection and radiation. At the microscopic level conduction results...

Paul Andersen explains how X inactivation works in mammals. This process was first described by Mary Lyon. Each cell in a female will have on activated and one inactivated X chromosome. This explains why almost all calico cats are female.

Paul Andersen explains the major plants structures. He starts with a brief discussion of monocot and dicot plants. He then describes the three main tissues in plants; dermal, ground and vascular. He also describes the plant cells within...