Cosmic Evolution: From Scientific Method to the Big Bang
The Scientific Method and Its Application to the Cosmos
The scientific method involves making observations, asking questions, forming hypotheses, and conducting experiments. Elegance, in this context, refers to the ability of a theory to explain a wide range of phenomena.
A scientific belief is typically backed up by experiments designed to test hypotheses. If several experiments do not contradict a hypothesis, we tend to believe it to be true. While this is not directly applicable to phenomena like
Read MoreKey Concepts in Physics: Fluids, Electricity, and Energy
Fluids and Pressure
- Atmospheric Pressure (P. ATM): The pressure that air exerts on the bodies that are on the surface of the Earth.
- Adhesion: The attraction between molecules of different classes.
- Barometer: A device that allows us to measure the atmospheric pressure.
- Fluids: Defined as a substance that flows easily and changes shape.
- Bernoulli’s Principle: For a perfect fluid, the sum of kinetic and potential energies and pressure anywhere within the liquid mass is constant.
- Absolute Pressure: The total
Understanding States of Matter and Energy Changes
States of Matter and Their Properties
Changes of State: When a substance changes its state, its mass is conserved. This is a physical change, meaning it does not produce a new substance. If the changes are reversed, the substance regains its original properties. Evaporation does not have to occur at the boiling temperature of the liquid; it involves only a few particles becoming a gas. In a liquid, particles have a range of energies. At the surface, some particles will have enough energy to escape
Read MoreUnderstanding Conservative Forces and Kepler’s Laws of Planetary Motion
Block 1
Conservative Forces
For many types of forces, the work done to move a body between two points depends on the path followed (e.g., frictional forces). However, this is not the case for a particular type of force called conservative forces. A conservative force is capable of returning the work done against it. These forces are characterized by performing work that only depends on the initial and final positions, not the path taken. Consequently, when work is done in a closed path, the net work
Read MoreElectrical Concepts and Wave Properties Explained
Electric Field
The electric field is the area of space around a load where electrical forces exert attraction or repulsion.
- The field strength depends on the load generator.
- The greater the load, the stronger the field.
- The further we move from the load generator, the weaker the field.
Capacitors
Capacitors store energy until required for use. They consist of two conductors, one positive and one negative, that support more capacity induction.
Ammeter
An ammeter measures the current in a circuit. It is placed
Read MoreMagnetic Fields: Properties and Laws
The Magnetic Field
The magnetic field is a region of space in which a point electric charge, value q, moving at a speed, suffers from a force that is perpendicular and proportional to the speed and the field, called magnetic induction or density magnetic flux.
Performance of Magnetic Field Lines
The performance of magnetic field lines can roughly estimate the magnetic field existing at a given point, taking into account the following characteristics:
- The magnetic field lines are always closed loops