Lesson 35: Human Limitations

There are limitations to what humans can do.

We cannot hear or see things which are tiny, too soft or well-hidden.
We cannot fly or walk very fast or too far without the aid of technology.


HOWEVER,

Human are able to overcome their limitations by using devices.
1. We can used telescope, magnifying glass and microscope to 
    see the fine details of an object.
( A )Telescope




( B ) Magnifying glass


( C ) Microscope




2. We can used telephone, megaphone and 
     microphone to speak loud enough for someone.
( A ) Telephone



( B ) Megaphone



( C ) Microphone


3. We used train, car and aeroplane to walk long distance.
( A ) Train



( B ) Aeroplane



( C ) Car

Lesson 34: Development of Technology

Human develop technology for the betterment of mankind. This development has made the world a better and more comfortable place to live in.

1. Technology in Agriculture
A long time ago, simple devices were used to dig holes, and loosen the soil. Later, animals were used to plough the land. 



Today, tractors were used on order to be done more quickly 



2. Technology in Communication 
A long time ago, telegraph and devices such as the telephone allow humans to communicate with each other in far away.

Telegraph

Radio

Telephone

Today,.....

These devices are known as telecommunication technology.

3. Technology in Transportation
Humans have invent a better transport as the technology changes. 



4. Technology in Construction

A long time ago, humans loved in caves and built houses from clay and parts of plants. However, these shelters were not safe. They were not strong and were easily destroyed.

Today, humans are now able to build bigger and taller buildings and most of the houses are built using bricks, concrete and steel which are strong.

Lesson 33: Planets, Planets How Are You?

1. Types of planets

• Mercury

- It is too close to Sun.
- The temperature is too hot to support life

• Venus

- A great amount of the heat from the Sun is trapped in its    
  atmosphere.
- It is hotter than Mercury

• Earth

-It has water, air and a suitable temperature to support life.

• Mars

- Almost all of its water is frozen.
- Scientists have not found any life there.

• Jupiter

- It is so big that all the others planets could fit inside it.

• Saturn

- It has three wide rings
- There can be seen with a telescope

• Uranus

-Uranus is lying on its side as it goes round the Sun.

• Neptune

- It is covered with a blue ocean of liquid methane.

• Pluto 

- Pluto is very cold because it is very far from the Sun.


2. Inner planets-Mercury, Venus, Earth and Mars


- All these planets are made of rocks
- Each of the inner planet has an atmosphere and it    
  contains air  
  which suitable for living things to survive.
- The atmosphere of the other inner planets is very thin 
  and poisonous to living things.


3. Outer planets-Jupiter, Saturn, Uranus, Neptune  
    and Pluto


-   They are mainly made of gases. 
-   Their temperature is too cold to support life.

Lesson 32: How far and How Big

Scientists have calculated that the Sun is one hundreds of times the size of Earth. Earth is four times the size of the Moon.


The distance from Earth to the Sun is 400 times the distance from the Earth to the Moon.

Lesson 31: Our Solar System

The sun and the nine planets are part of the Solar System




1. The sun is in the centre of the Solar System



2. Asteroids are huge chunks of rocks that travel around 
    the Sun



3. Meteors are tiny rock which probably come from the asteroid 
    belt


4. Comets have long glowing tails.



5. All the nine planets move around the Sun in a large oval path.


6. The nine planets are:

• Mercury
• Venus
• Earth
• Mars
• Jupiter
• Saturn
• Uranus
• Neptune
• Pluto 

Lesson 30: Rusting

Iron objects can rust. Therefore, how can you prevent them from rusting?
Difference between a rusted nail and unrusted nail
Rusted nail

- The nail with rusted surface is dull and rough
- When you scrap it off, the rusted surface will blister off.

Unrusted nail

-The clean non-rusted surface stays shiny.

There are different ways to prevent iron from rusting. We can keep it away from air and water. This can be done by:
( A ) Spay painting



( B ) Greasing or oiling



( C )Plastic coating



( D ) Tin plating

Lesson 29: Reuse, Reduce and Recycle

Natural and man-made materials are very limited. Therefore, we should reuse, reduce and recycle them.

( A ) We can reuse tins, cans and bottles


( B ) We should try to reduce the use of paper     
         because we have to cut many trees in order to     
         produce papers     


( C ) We should recycle newspapers instead of burn