1. Electrical ConductivityPrathomsueksa 5

2. Vocabulary 3. conductivity 4. conductor 5. electron 6. proton 7. battery 8. StructureWe use relative clauses to giveadditional information aboutsomething without starting anothersentence. By combining sentenceswith a relative clause, your textbecomes more fluent and you canavoid repeating certain words. 9. Recognize a relative clauseA relative clausealso called anadjective or adjectival clausewill meet three requirements. 10. -First, it will contain a subject and verb.-Next, it will begin with a relative pronoun[who, whom, whose, that, or which] or arelative adverb [when, where, or why].-Finally, it will function as an adjective ,answering the questions What kind? Howmany? or Which one? 11. The relative clause will follow one ofthese two patterns: Relative pronoun or adverbsubject verb + Relative pronoun as subject verb 12. ExampleRelative pronoun verbWho continued to play videogames until his eyes were blurrywith fatigue. 13. Example Relative pronoun A conductor is a material whichcontains movable electriccharges. verb 14. ExampleRelative pronoun verbThat dangled from the oneclean bathroom towel. 15. Electrical ConductivityElectrical conductivity is a materials abilityto conduct an electric current when anelectrical potential difference is appliedacross it. It is also known as specificconductance, and should not be confusedwith conductance which is a property of acomponent, whereas conductivity is aproperty of the substance from which thecomponent is made. 16. The SI unit of electrical conductivity is thesiemens per metre (S/m). Conductivity is theinverse of resistivity. The conductivity, , isgiven in terms of current density, J, and electricfield strength, E, using the expression:J = E (Siemens /m)J current density conductivityE electric field strength 17. Electrical conductorA conductor is a material which containsmovable electric charges. In metallicconductors such as copper or aluminum ,the movable charged particlesare electrons . Positive charges may also bemobile in the form of atoms bound in acrystal lattice which are missing electrons,or in the form of mobile ions, 18. such as in the electrolyte of a battery, or asmobile protons in protonconductors employed in fuel cells. Ingeneral use, the term "conductor" isinterchangeable with "wire."Insulators arenon-conducting materials with few mobilecharges and which support onlyinsignificant electric currents. 19. Experiment 20. Materialslampwire batteryl 21. clear adhesive tape razorpencil lead 22. coinsspoon key 23. Activity1. Make a group of four ( but not now )2. Lets do the experiment by consulting with your friends and draw a picture.3. Come in front of the class to show your experiment and conclude the experiment please show your own song and dance follow the song. 24. ProceduresPeel both sides of wire; the first side ofwire has to be longer than another side. 25. Connect the wire to the anode ofbattery and bind another wire to thebase of the lamp. 26. Place the cathode of battery and thebase of the lamp on each side of thepencil lead. Then, notice thebrightness of the lamp. 27. Gradually move the base of the lampfollow the pencil lead ,and notice thebrightness of the lamp. 28. ConclusionWhen we gradually move the base of the lampfar from the pencil lead; the brightness of thelamp will be dim up. If the space of the batteryand the lamp increase; the electric current thatpasses through the pencil lead will be decreasebecause the pencil lead is not a good conductor.