U_5_1_Basic terminology

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1 U_5_1_Basic terminology
Física y química 3º E.S.O. THIRD TERM Unit 5: Electricity and magnetism U_5_1_Basic terminology and concepts

2 Bloque 4. El movimiento y las fuerzas.
4.1. Las fuerzas. Efectos de las fuerzas. 4.2. Fuerzas de especial interés: peso, normal, rozamiento, fuerza elástica. 4.3. Principales fuerzas de la naturaleza: gravitatoria, eléctrica y magnética. Criterios de evaluación C.E.4.8. Conocer los tipos de cargas eléctricas, su papel en la constitución de la materia y las características de las fuerzas que se manifiestan entre ellas. . Estándares de aprendizaje evaluables E.A Explica la relación existente entre las cargas eléctricas y la constitución de la materia y asocia la carga eléctrica de los cuerpos con un exceso o defecto de electrones. E.A Relaciona cualitativamente la fuerza eléctrica que existe entre dos cuerpos con su carga y la distancia que los separa, y establece analogías y diferencias entre las fuerzas gravitatoria y eléctrica. C.E.4.9. Interpretar fenómenos eléctricos mediante el modelo de carga eléctrica y valorar la importancia de la electricidad en la vida cotidiana. E.A Justifica razonadamente situaciones cotidianas en las que se pongan de manifiesto fenómenos relacionados con la electricidad estática. C.E Justificar cualitativamente fenómenos magnéticos y valorar la contribución del magnetismo en el desarrollo tecnológico. . E.A Reconoce fenómenos magnéticos identificando el imán como fuente natural del magnetismo y describe su acción sobre distintos tipos de sustancias magnéticas. E.A Construye, y describe el procedimiento seguido pare ello, una brújula elemental para localizar el norte utilizando el campo magnético terrestre. C.E Comparar los distintos tipos de imanes, analizar su comportamiento y deducir mediante experiencias las características de las fuerzas magnéticas puestas de manifiesto, así como su relación con la corriente eléctrica. E.A Comprueba y establece la relación entre el paso de corriente eléctrica y el magnetismo, construyendo un electroimán. E.A Reproduce los experimentos de Oersted y de Faraday, en el laboratorio o mediante simuladores virtuales, deduciendo que la electricidad y el magnetismo son dos manifestaciones de un mismo fenómeno.

3 Lesson 1 - Basic Terminology and Concepts
Lesson 2 - Methods of Charging Lesson 3 - Electric Force Lesson 4 - Electric Fields

4 Lesson 1 - Basic Terminology and Concepts

5 Electrical Charge Electrical charge is a fundamental property of protons and electrons The center of an atom is made up of particles called protons and neutrons. - Electrons, move around the center of the atom. - Electrons have negative electric charge - Protons have positive electric charge. - Neutrons have no electric charge.

6 Electric Charge There are two kinds of electric charge: positive and negative A neutral atom has the same number of protons and electrons. So, the positive and negative charges cancel each other out. The addition of energy to an atom can cause the electrons to leave the atom. An atom that loses electrons becomes positively charged An atom becomes negatively charged if it gains extra electrons.

7 Electric Charge There are two kinds of electric charge: positive and negative All objects are composed of atoms. A neutral object has the same number of protons and electrons. So, the positive and negative charges cancel each other out. An object with more protons than electrons becomes positively charged An object with more electrons than protons becomes negatively charged

8 How is electric charge transferred?
An object whose atoms lose electrons becomes positively charged An object whose atoms gain electrons becomes negatively charged The electrons contained within the objects are prone to move or migrate to other objects, although electrons are bound more tightly to some atoms and molecules than to others.

9 Static electricity An object whose atoms lose electrons becomes positively charged An object whose atoms gain electrons becomes negatively charged The electrons contained within the objects are prone to move or migrate to other objects.

10 Static electricity The buildup of unbalanced electric charges on an object is called “static electricity” When electric charges on an object are unbalanced there is static electricity

11 Static electricity How avoid being shocked when exiting your car?

12 Interaction between charges
Physical force between electric charges Opposite charges attract Two positive charges repeal each other Two negative charges repeal

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14 Law of conservation of charge
Is new electrical charge created or destroyed? Neither protons nor electrons in an object can be created or destroyed An object becomes charged when electric charges move from one place to another. Electrons can be transferred from one object to another, but they are no new electrons. The law of conservation of charge states that in a closed system, the total amount of charge is conserved since charge can neither be created nor destroyed.

15 The SI unit of charge Electrons and protons are tiny and have a very small charge. Most common applications of electricity require the charge of billions of electrons and protons. Useful things like lighting a bulb requires thousands of millions of electrons 1 coulomb (C) is equal to the charge of 6.25 x 1018 electrons or protons. This is electrons or protons

16 1 coulomb (C) is equal to the charge of 6.25 x 1018 e- or p+
The SI unit of charge 1 coulomb (C) is equal to the charge of 6.25 x 1018 e- or p+ e.g. : There are about 8.49 X 1022 free electrons per cubic centimeter of copper. 1 coulomb (C) q C 6·25 x 1018 electrons X 1022 free electrons 1 coulomb (C) 6·25 x 1018 electrons q 8.49 X 1022 free electrons 13,605.8 C The charge provided by the free electrons in 1 cm³ is 13,605.8 coulombs of free electrons

17 What is the charge of a single electron in coulombs?
1 coulomb (C) is equal to the charge of 6,25 x 1018 electrons or protons. 6.25 x 1018 electrons 1 electron - 1 coulomb (C) q C Q = x C What is the charge of a single proton in coulombs? Q = x C

18 Multiples and submultiples of charge unit in SI
SI Prefixes Table Calculate the charge of a single proton in picocoulombs The 20 SI prefixes used to form decimal multiples and submultiples of SI units: 1 pC = C 1 pC +1.60 x 10-7 pC Q = x C C

19 Multiples and submultiples of charge unit in SI
What is the charge of the free electrons in 1 cm³ of copper in kC? SI Prefixes Table Remember the charge of the free electrons is 13,605.8 C The 20 SI prefixes used to form decimal multiples and submultiples of SI units: 1 kC = 10 3 C 1 kC Q = - 13,605.8 C kC 10 3 C

20 Multiples and submultiples of charge unit in SI
A honeybee acquires a charge of +23 pC as it flies back to its hive. As it approaches the hive entrance, what is the magnitude of the charge of the honeybee in Coulombs?

21 Multiples and submultiples of charge unit in SI
A honeybee acquires a charge of +23 pC as it flies back to its hive. As it approaches the hive entrance, what is the magnitude of the charge of the honeybee in Coulombs? 1 pC = C C Q = +23 pC x = +23 x C= +2.3 x C 1 pC