Science 4th primary 2nd term unite2 lesson 4

** most of equipments at home work by electricity.

** such as : computer – refrigerator – television.

** these equipments need wires to connect them by electricity ( current electricity ).

** there is another kind of electricity does not flow in wires and is called ((static electricity.))

Phenomena related to static electricity:

* The vision of light in the sky ((Lightning)).

* standing or your hair when you combing it by plastic comb.

* Hearing a sound when you putting off your clothes in some days or vision of a flash.

What is the reasons of occurrence of those phenomena in your opinion?!

………………………………………………………………………………………………………………………………………..

Formation of electric charges is the reason of these phenomena.

This charge is called ((static electricity)).

Static electricity:

It is formed from electric charges that remain on an object.

Activity >>> Balloon and generation of electricity.

Materials:

- balloon

- a piece of wool

- little amount of powdered sugar.

- a thread.

Procedures:

- Blow a balloon and tie its opening by a thread.

- rub the balloon by piece of wool.

- close the balloon to sugar.

What do you observe?

………………………………………………………………………………………………………..

Conclusion:

On rubbing a balloon by a piece of wool.

Electric charges are formed on its surface and attract sugar to them.

Light of lightning:

Lightning happens when negative electric charges found in clouds meet with positive electric charges rising from earth.

Activity >>> small bits of paper and the charged ruler.

Materials :

- plastic ruler

- small bits of paper

Procedures:

- close the ruler to the small bits of paper.

- are the bits of paper move or not?!

…………………………………………………………………………………………………………..

- rub the ruler by your hair several times.

- close the ruler to the small bits of paper.

What do you observe?!

…………………………………………………………………………………………………………

Explanation:

Before rubbing the ruler, there is no electric charges on the ruler.

After rubbing electric charges are formed on ruler that attracted the small bits of paper to them.

Rubbing of objects generates static electricity.

Activity >>> to show the concept of electric current.

Materials:

- pocket torch

- battery for the torch.

Procedures:

Put the battery inside the torch then press on its key.

What happens to its lamp?!

……………………………………………………………………………………………………………..

Explanation:

The battery pushes electric charges in wires.

Electric charges reaches to the lamp causing its lighting.

Electric current flows in one direction, so it called direct current.

Current electricity

They are electric charges that flow through connecting wires for long distances.

Activity >>> make a battery from a lemon !!

Materials:

- flexible lemon

- a rod of copper

- rod of zinc or iron

- lamp with base

- connection wires.

Procedures:

- press on the lemon several times until it becomes flexible.

- put copper rod far from the zinc rod by 3 cm in the lemon.

- connect the rods by the lamp as in figure.

What do you observe?!

……………………………………………………………………………………………………………………

Conclusion:

……………………………………………………………………………………………………………………

Exercise

You can do the pervious activity by using an orange or another fruit.

Activity >>> formation of an electric circuit.

Materials:

- battery

- lamp with a base

- connecting wires have uncovered ends

- electric switch.

Procedures:

- set up an electric circuit as shown in the opposite figure.

Perform the following steps in the table and record your observation about the state of lamp in each step.

State of lamp

Steps of performance

No light

Light

1 – on closing the circuit by the switch.

2 – on opening the circuit by the switch.

3 – on removing battery then close the circuit

4 – on connecting the battery and closing the circuit.

In light of your observations, answer the following questions:

1 – what is the function of battery?

……………………………………………………………………………………………………………………….

2 – what is the benefit of switch?

………………………………………………………………………………………………………………………

3 – what is the importance of connecting wires?

……………………………………………………………………………………………………………………..

The battery:

It is the source of electric current.

The switch:

It is used to close and open the electric circuit.

The wires:

They are used to transfer electric current from battery to lamp.

The electric circuit:

It is the path of electric current.

Attention:

Don't use the electricity of homes in performance of this activity or any other activates.

Mention some equipment that are present at your home and work by electricity?

1 – Television

2 – washing machine

3 – Refrigerator

4 – Heater

5 – computer.

Enrichment information:

* some inventors of electric equipments:

* Marconi >>> the inventor of radio (born in Bolivia in 1874)

* Jon Bird >>> the inventor of television (born in Britain in 1888)

* Volta >>> the inventor of generating electric current in 1800.

Summary

Comparison between static and dynamic electricity!!

Dynamic electricity

Static electricity

Points of comparison

It is the electric charge that flow in connecting wires for long distances.

It is formed from electric charges that remains in an object.

Definition

Electric circuit

Rubbing

Method of generation

Used to operate fridge, t.v and computer

-vision of lightning in sky

-standing of your hair when you comp it.

-hearing sound when you putting off your clothes.

Examples:

Glossary

Static electricity

كهرباء استاتكيه

Thread

خيط

Powdered sugar

سكر بودره

Electric charge

شحنه كهربيه

Inflated balloon

بالونه منتفخه

Wool

صوف

Attract

يجذب

Bits of paper

قصاصات ورق

Phenomena

ظاهره

Vision

رؤيه

Lightning

البرق

Positive charge

شحنه موجبه

Negative charge

شحنه سالبه

Comb

مشط

Stable

ثابت

Flow

يمر

Pocket torch

كشاف الجيب

Connecting wire

اسلاك توصيل

Electric circuit

دائرة كهربيه

Apply

تطبيق

Uncovered end

نهايات اسلاك غير معطاه

Electric switch

مفتاح كهربى

Copper

نحاس

Rod

قضيب

High power

تيار كهربى قوى

Closed path

مسار مغلق

Questions on lesson:

Complete the following statements:

1 – most of equipments at home work by …………………………………

2 - ……………………………… is the electricity that does not flow in wires.

3 – equipments need …………………………… to connect them by electricity.

4 – the vision of light in the sky is called ……………………………..

5 - …………………………………….. is formed from electric charges that remain on an object.

6 – lightning happens when ……………………. Electric charges found in clouds meet with ……………….…… electric charges rising from earth.

7 –rubbing of objects generates ……………………………… electricity.

8 – the …………………………….. pushes electric charges in wires.

9 - ……………………………………. Are electricity charges that flow through connecting wires for long distances.

10 – we can use …………………………. Fruit to generate electricity.

11 – on closing the electric circuit ,the lamp will ……………………………..

12 - ………………………… is the source of electric current.

13 - ……………………………. Used to transfer electric current from battery to lamp.

14 – the electric …………………………… is the path of electric current.

15 - ………………………… is the inventor of Radio.

16 - ………………………. Is the inventor of television.

17 – Volta is the first inventor of …………………………………. Electric current.

18 – Television , ……………………… and ……………………… are examples of home equipments that operate by electricity.

Choose the correct answers:

1 – lightning that occurs in sky is phenomenon related to …………………….

A: static electricity b. dynamic electricity c. potential energy d.kinetic energy.

2 – to make an electric circuit , we need …………………………

A: key and lamp b.connecting wires c.battery d.all the previous.

3 – the closed path of electric current is called ………………………

A: electric current b. battery c. electric circuit d. switch.

4 – all the following equipments work by the current electricity except ………………………

A: blender b. television c. fan d. windmills.

5 – washing machine and electric heater work by ………………………….

A: static electricity b. current electricity

c. both static and current electricity d. no correct answer.

6 – static electricity is produced from …………………………

A: flow of electricity charges in wires.

B .rubbing your hair by plastic ruler.

c. putting battery inside torch.

d. a and c

What happens when:

1 – rubbing your hair by a plastic comb?

…………………………………………………………………………………………………………………………………….

2 – rubbing a plastic ruler by a piece of wool?

…………………………………………………………………………………………………………………………………..

3 – rubbing a flattened balloon by a piece of wool then closing it to your hair?

……………………………………………………………………………………………………………………………………

4 – Removing the battery from a closed electric circuit?

……………………………………………………………………………………………………………………………………

Give reasons:

1 – attracting the small bits of paper to a ruler that was rubbed by your hair?

……………………………………………………………………………………………………………………………………

2 – attracting a balloon rubbed by the wool to a wall?

……………………………………………………………………………………………………………………………………

3 – it is forbidden to use electric current at home for performing an activity?

……………………………………………………………………………………………………………………………………

Suggest a way to decrease the consumption of electricity?!!

………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………

The electric equipments used at home

Current electricity (Dynamic)

Static electricity generation

The Electricity

Ms. Marim 1