UNIT 4 Standard No:23 LESSON 1

Open physics for you pg :

Electric circuit دائرة كهربية

Electric current تيار كهربي

Complete circuit دائرة مغلقة Incomplete circuit دائرة مفتوحة

Battery بطارية Bulb مصباح

Switch مفتاح Wire سلك كهربي

Potential difference فرق الجهد

ACTIVITY 1 : Each group has : 2 wires Bulb Battery

ACTIVITY 1 : Procedure : Use the items you have and make an electric circuit which will turn on the bulb. Time : 3 min.

electric circuit ( A ) Battery Bulb Wire In this circuit : 1- Did the electricity flow? 2- How do you know this? Complete circuit

2- Where did the electricity come from ? To answer this question we must go back to the atom structure. The atom has three particles : Electron : it has a ……………..charge proton : it has a ……………....charge neutron : it is ……………. positive negative neutral

Free Electrons Can Move

Free Electrons can Move from Atom to Atom The free electrons are attracted to atoms where there is an electron missing. It will fill the space just left empty by the first free electron. When this happens all the time, the movement of electrons becomes the "current".

Electricity - electrons moving through a metal wire.

ACTIVITY : Procedure : 1-Use the items you have and make a complete circuit which has no light bulb 2- keep holding the wires attached to the battery for 2 min.

Does the electricity flow in the wires ? There is no lights on After 2 minutes What happened to the wire ? It became warmer

ACTIVITY : Procedure : 1-Use the items you have and make a complete circuit which has no battery

ACTIVITY : Did the bulb turn on ? Why ? Did the electricity come from wire or battery? No Because there is no battery Most wires are made of copper which has free electrons

If the electrons are already in the wire, why do we use battery ? Look at this example with water. Water pump A B C D E F Water pipes You see a system ofpipes full of water. Would the water move from A to F by itself ? What do we need?

A V A B C D F E Find out the meaning of these symbols : Compare this with an electrical circuit. Instead of pipes, we have Instead of water, we have Instead of a pump, we have wires electrons a battery

A V A B C D F E switch Electrode Source battery wire voltmeter Ammeter

What is an electric current? An electric current is a flow of microscopic particles called electrons flowing through wires and components. + - In which direction does the current flow? from the Negative terminal to the Positive terminal of a cell.

Look at the two circuits below. Will the circuit give out light or sound when the switch is closed?

Q:Charge: 1 coulomb is the amount of charge that passes a point when a current of 1 ampere flows for 1 second. Q = It electric current is the rate of flow of charged Particles (Ampere) The charge on 1 electron is 1.6× c q=n×e Amount of charge =number of electron ×charge of one electron

Solve problem: A Current of 0.50A passes through a lamp for 2.0 minutes a) How much charge passes through the lamp ? b) How many electrons pass through the lamp?

What are conductors and insulators?

Warm Up 1. In the diagram above, the water in the pan is changing from a liquid to a gas, or ____. a. Melting c. condensing b. freezingd. evaporating 2. What is matter? a.The amount of matter something contains. b.Everything in the universe that has mass and takes up space c.The amount of salt in water d.The amount of space that matter takes up. 3. Study the picture above. When the sun comes out, the snowman melts, or changes from ____. a.solid to liquid b.liquid to solid c.gas to liquid d.solid to gas 4. Buoyancy is__________ a.The ability for an object to float b.To form a solution with another material c.The amount of matter something contains. d.evaporation

What is a conductor? A conductor is something which allows electricity to flow through. An example of a conductor is: – Scissors – Paper clip – Aluminum foil – Iron – Steel – Copper

What is a Insulator? An insulator is what makes electricity from not flowing Examples of insulators are: – Cotton – Paper – Plastic – Glass – Rubber

Inquiring Minds Want to Know! Conductor or Insulator? That is the question! Now take the bag of materials and spread them out in front of you. Draw the following table in your journal. As you test each item, record whether it was a conductor or and insulator with a Item Conductor InsulatorDid the bulb light? Spoon Paper clip pencil Rubber band eraser Foil Nail coin