How do we use electricity and magnetism?

How do we use electricity and magnetism? (part 1)Chapter 12: Lesson 5:

What is matter?Matter is everything around us that has mass and volumeWhat is matter made of?Matter is made of very small building blocks called ATOMS

What are Atoms?Smallest part of any matterCannot be seen with a normal microscope (use electron microscope)Example:Oxygen HydrogenN.B. Water (HO)is made of 1 atom of oxygen and 2 atoms of hydrogen)

WHAT DO ATOMS LOOK LIKE?Matter is made up of atoms.

+

+

+

+

Proton (positive charge) neutron (neutral)electron (negative charge ,Electrical charge)atom

nucleus

Where do charges come from?If electrons = protons neutral ,So atoms are neutral

If electrons > protons gaining electrons, negative charge, electrical chargeIf electrons < protons losing electrons, positive charge

Positive and Negative ChargeOpposites charges attractSame charges repel

Choose the correct answer1) Matter is made up of tiny particles called .A) atomsB) ballsC) hoops2) Inside the atom, there are and charges.A) positive and positiveB) negative and negativeC) negative and positive

3) When the positive charges are equal to the negative charges, matter is _______________ .A) positively chargedB) neutralC) negatively charged4) charges move easily than _____________ charges.negative, positive B) positive, negative C) neutral, positive

5) Negative and positive = __________ A) AttractB) RepelC) No change

Electricity is divided in to 2 types:

1.Static electricity 2. Current electricity (A flow of electrical charges through a path way called : circuit)

1.Static ElectricityThe build up of an electric charge on the surface of an object.

The charge builds up but does not flow.

Static electricity does not move. It is stored.

ElectronsAre located on the outer edges of atomsthey can be moved.A concentration of electrons in an atom creates a net negative charge.If electrons are stripped away, the atom becomes positively charged.

Examples of static electricity

Where do charges come from?When a balloon rubs a piece of wool...

electrons are pulled from the wool to the balloon.The balloon has more electrons than usual.+++++The balloon: charged, The wool: +chargedwool

Try rubbing a balloon against a wool clothPlace the balloon over anybodys hair and watch what happens Balloon Experiment

When we rub the balloon against a wool cloth, the balloon gains a negative charge (-)The (-) charge in the balloon attracts the (+) charge in the hair causing the hair to stand.Explanation

Static Electricity

The production of a charge in an uncharged body by bringing a charged object close to itWhen negatively charged rod is put near a metal can...electrons of the can are pushed away from the rod. top of the can: positive& attraction > repulsion+++++metal can-----

------- buttom of the can: negativeinduced charges

attractionrepulsion

Attraction of uncharged objectsSimilarly, when charged rod is close to paper scrap...

-------

molecules of paper align. attraction between the rod and + charge > repulsion between the rod and - charge.paper

+

+

+

+

+

+

+

+

attractionrepulsion

Try rubbing a comb against a wool cloth

The comb will gain a negative chargeBring the comb near some pieces of paper Comb Experiment

Initially the paper is uncharged, but the comb attracts the positive charges in the paper and repels the negative charges.

Lightning(Is caused By)Rubbing of rain drops and ice inside a storm cloudWhen the (-) charges get large enough they jump to the ground as lightning.

3)The _________charges on the balloon attract the _________ charges on the wall . The balloon sticks to the wall.

1)A balloon and wool cloth are ____________.

2)By rubbing the balloon with the wool,_____________ charges goes to the balloon.

Complete:

The end

Current Electricity(Current electricity)A flow of electrical charges through a circuit.(Circuit is a path along which electric current flows)

Circuits should have 3 partsPower sourceBattery (cell)LoadBulb / MotorConnectorsWiresPower sourceLoadConnectors

Types of circuitsOpen circuitsBroken circuits (Incomplete)Closed circuitsUnbroken circuits(Complete)

CIRCUITS SYMBOLS:1) Battery

2) Bulb

3) Wires(A straight line)

4) Switch (off)

5) Switch (on)

6) Motor7) Buzzer

The end

Series and Parallel Circuits

Series CircuitSeries circuit - has only one path through which the electricity can flow.

In the above diagram, the electricity flows through both loads.

The current decreases because the resistance increases. Ohms Law

says that I=V/R. The voltage in the system is constant, resistance increases.

Parallel CircuitsA parallel circuit has multiple paths through which the electricity can flow.

In a parallel circuit, the current though one path may be different than the current through the other path.

PARALLEL CIRCUITPlace two bulbs in parallel. What do you notice about the brightness of the bulbs?

Add a third light bulb in the circuit. What do you notice about the brightness of the bulbs?

Remove the middle bulb from the circuit. What happened?

Simple Circuits

Series circuitAll in a row1 path for electricity1 light goes out and the circuit is broken

Parallel circuitMany paths for electricity1 light goes out and the others stay on

Conductors and Insulators

A conductor is a substance through which electric charge flows readily. An insulator is a substance that strongly resists the flow of electric charge.