Daniell Cell Lecture
Mr. Grodski
Charles-Augustin de Coulomb 1736 - 1806
Coulomb was a French military engineer and physicist. He is best known for developing what is now known as Coulombs law. He discovered first an inverse relationship of the force between electric charges and the square of its distance and then the same relationship between magnetic poles. Later these relationships were named after him as Coulombs law.
The SI unit of electrical charge, the coulomb was named in his honour.
Charles-Augustin de Coulomb 1736 - 1806 - Torsion Bar Experiment
Coulomb Unit
The coulomb (symbol: C) is the International System of Units (SI) unit of electric charge. It is the charge (symbol: Q or q) transported by a constant current of one ampere in one second:
It is equivalent to the charge of approximately 6.242×1018 (1.036×10−5 mol) protons, and −1 C is equivalent to the charge of approximately 6.242×1018 electrons.
André-Marie Ampère 1775 – 1836)
Ampere was a French physicist and mathematician who was one of the founders of the science of classical electromagnetism, which he referred to as "electrodynamics". He is also the inventor of numerous applications, such as the solenoid (a term coined by him) and the electrical telegraph.
The SI unit of measurement of electric current, the ampere, is named after him. His name is also one of the 72 names inscribed on the Eiffel Tower.
The SI unit of charge, the coulomb, "is the quantity of electricity carried in 1 second by a current of 1 ampere". Conversely, a current of one ampere is one coulomb of charge going past a given point per second:
In general, charge Q is determined by steady current I flowing for a time t as
Q = It.
André-Marie Ampère 1775 – 1836)
Energy – ability to do work
work = Force x Distance
Mass x Acceleration
Kg x m
sec2
x m
=
Kg m2
sec2
or
Kg m2 sec-2
Joule
SI unit
Only when SI units were utilized internationally did joules become used as the common energy unit. Older heat units that dealt with water were used initially (BTU, and calorie).
James Prescott Joule – 1818-1889
Joule studied the nature of heat, and discovered its relationship to mechanical work (see energy). This led to the theory of conservation of energy, which led to the development of the first law of thermodynamics.
The first unit or equivalent of energy was given determined by Joule by dropping 773 lbs one foot that caused enough motion to increase the temperature by 1 degree Fahrenheit in a pound of water (2.2 Kg). These were called foot pounds.
From Your Reference Tables:
SI Unit of Heat or Energy
This is a fruit Juice Nutritional Label from Amsterdam:
A Nutritional Lab from China:
A Nutritional Label from England:
256 kJ
61 kcals
=
~4.18
This means that there are about 4.18 kiloJoules for every 1 kilocalorie or 4.18 J for every calorie.
From Your Reference Tables:
Our Nutritional Labels.
Notice that the word Calorie is in capitals because they (FDA) do not think that the US population can handle the concept of kcals or kilocalories thus they put a capital C in front of the word calorie to denote kilo or large amount of calories.
Alessandro Giuseppe Antonio Anastasio Volta - 1745 – 1827
He was an Italian physicist, chemist, and a pioneer of electricity and power,[who is credited as the inventor of the electrical battery and the discoverer of methane. He invented the Voltaic pile in 1799, the first battery to refute the idea that electricity is biologically inherent.
Voltage -
The voltage between two points is equal to the work done per unit of charge against a static electric field to move a test charge between two points. This is measured in units of volts (a joule per coulomb); moving 1 coulomb of charge across 1 volt of electric potential requires 1 joule of work.
A voltage may represent either a source of energy (electromotive force, E0cell) or lost, used, or stored energy (potential drop).
Voltage verse Amperage
Voltage - Electromotive Force or Potential difference of charge
Voltage - Electromotive Force or Potential difference of charge
Voltage - Also a measure of spontaneity
Voltage that we read from volt meters or galvometers are also a measure of spontaneiety or Entropy!