Rock and Minerals

Rock and Minerals 

 Our earth is made of  soils  and rock. rocks  are found  everywhere  in mountains , sea s and ground. All rocks on the  earths  are made up of  minerals . some rocks  contain only one minerals , while , other may contains  many minerals .

 

 

Types of rocks 

 On the basis of  their  formation, rocks  are of three types  igneous, Sedimentary and  metamorphic 

Igneous rocks 

 The  centre of  the earth is made of  hot molten rock called magma .When a volcano erupt , this magma flows out  onto the surface  of  the earths . The magma that reaches  the surface  of the earths  is called   larva . Larva cool down and  solidifies  to form hard rocks  igneous rocks .

Type of igneous rocks 

1.Basalt : It is  an igneous rock formed  by the rapid cooling  of the larva  on the earths  surface . it is  dense and dark in color  and  has fine  grains . The edge of this  rock is  called  is very sharp. They are called scoria  rocks.

2.Granite : It is formed  when magma cools below the earths  surface , it is  the most  common igneous rocks . It may be black, grey, white or pink in colour. it is very hard and therefore, used  for flooring of houses , making  statues and paving roads

3. Pumice : It is  light , grey or cream- colored  rock formed by quick cooling  of frothy lava . It is  the only rock  that float . It  has many holes  because  of   the air  trapped  insides  it can float . it  has many holes  because  of the  air  trapped  inside  it at the  time  of its  formation .

 it is used  as  scrubbing  stone  to remove  rough dead  skin from the body. Dentist  use  powdered  pumice for polishing  our teeth

4. Obsidian : it is formed  by quick cooling  of larva . it looks like  a  glass and is black in co

lour . due  to its  sharp edges, it  is use  in making  or cutting  of jewellery. 

Sedimentary rocks

Sedimentary rocks  are formed  from pebble , sand  mud  or clay that gets  deposited in seas and oceans . Repeated  heating  and cooling  of mountain by  rain, wind  and  sunlight  wear down the rock. These small pieces  of rocks  are  carried down by rivers  and  strong  wind s into the lakes  and seas . They sink to the  bottom and  settle  down from  layers called sediments . As the time passes  by , more  sediments  build up that press  down the layers.  continuous pressure  upon the lower layers  hardens them into rocks . Such rocks are  called  Sedimentary rocks . major  portion of the earths  surface is covered  with sedimentary rocks  .

Types of sedimentary rocks 

1.Sandstone : It is formed  when small particles  of sand  get compressed  and  cemented  together . Sandstone  mostly consist of  a  mineral called quartz. it is  widely used  for making  building . Many of our  old building  in Delhi, Agra  and Rajasthan are  are made up of  sandstone .

2. Conglomerate : it is solid  mass of pebbles , sand  and  gravel cemented  together  with minerals like  silks  and  calcium carbonates . It is mostly orange  or grey in colour . it  can be  withstand  weathering . it is used in construction and  for polishing  ornaments .

3.Shale : it is a smooth sedimentary rocks  formed  when  layers  of  clay hardens . It is  used  to make  tiles  and bricks 

4. Limestone: Lime stones  are made  of minerals  called  calcite  this minerals  comes  from Shells  of sea  creatures. when shells and skeletons  of millions of  tiny sea  creature s  settle down in the sea  bed , that from layers . These layers harden to form limestone . Chalk is a limestone  rock. cement  and lime  are also made using  lime stone . it is  also used  in  making  glass and  for separating  pure metals  form their ores .

Metamorphic rocks 

 Metamorphic rocks  are formed   from igneous rock or sedimentary rocks . when igneous rocks  or sedimentary rocks  are subkjecteds  to immerse    heat or pressure  inside the earth's , the  minerals  content  of these  rocks  changes . these   changed  rocks  are known as  metamorphic  rocks . These  changes  make  them harder  and   tougher .

Types of  metamorphic rocks 

1. Marbles : When lime stone I A sedimentary rock ) undergoes  several changes , it form marbles . It is found  in various  colour . It  can be  carve and polished  easily . it is used  for making  writing  slates  blackboard and roof  tiles .

2. Slate: When shale ( a sedimentary rocks ) undergoes several changes  , it forms  slate . It is dark grey in colour . It can easily  be split  into thin sheets . it is used  for making  writing  sltes  black board  and roof  tiles .

3.Gneiss : when granite ( an igneous  rock ) undergoes many changes , it form gneiss. during  its formation, the  minerals  within it get separated  to  form light  and dark bands of  different  colours  that can be seen separately. it  often glitters  because  of the   presence  of shiny mica 

 4.Quartzite: When sandstone ( A sedimentary rock) undergoes  several changes , it form Quartzite . It is  a hard  rock and can even scratch steel. it is used  to make  Statues  . It  is  also used  in making  glass and  in  ceramic industries 

Minerals :

 Minerals  are underground natural resources . Some are simple  substances and  some  are complex ones . rocks are also formed from minerals . Coal and marble are  examples of non metallic  minerals  Hematite and   bauxite  are some  examples  of  metallic minerals 

Uses of minerals  and  Rocks :

 We use various  rocks and mineral in our  daily life in different  ways :

1. We get useful metals from the rocks :

 Different metals are extracted  or mined from minerals . A minerals  from which metals  can be extracted  is called  an ore . We get iron, aluminum , copper , and zinc  from hematite , bauxite , copper  pyrites and calamine  ores  respectively. These metals  are commonly used  for making  utensils , machine , furniture , wires, etc . precious metals  like  gold , silver  and platinum are used  for making jewellery. 

2. we get  fuels  from rocks and minerals 

 Coal, petrol, diesel, kerosene , LPG, CNG, etc  are fuels  that we  use  in our daily life .

1. Coal: It is valuable natural resource . it is formed  from the remains of plants and  animals  buried  millions of years  ago. Due to high temperature and pressure  inside  the earths  these  remains  of plants  turned  into coals . It is widely used  for cooking  , producing  electricity , making plastics ,nylon, fertilizers and  in various  industries  as fuels .

 

 

2. Petroleum : It is dark colored  , thick crude  oil, It is  also called  black gold . Petroleum was  formed when plants  and  animals got buried  under  the  sea  millions of  years  ago. Due  to  high pressure  and temperature , their dead  bodies  got  converted  slowly into  petroleum.

We get LPG, CNG, petrol, diesel and kerosene  from petroleum, it is used  in automobiles  as fuels  and  in making  chemicals  paints , plastics , fertilizers , medicines  cosmetics  and produce  electricity .

 

3.Uranium: It is  not a minerals  but  found  with mineral. It is used  for producing  tremendous amount of energy . This  energy is called  nuclear energy . Atomic  power  plants  us  uranium to produce  nuclear energy.

3. We  get Gemstones  form the rocks

 Many minerals  are  very hard and found  in the form of  crystals . They are cut and polished  into beautiful stones  called gemstones . Diamond , ruby, emerald  and  sapphire are  some  gemstones 

used in making Jewellery.

 

 

 4. We get Fertilizers  from the minerals 

 Some  of the minerals , like  sulfates  and nitrates  are  added as fertilizers  to the  soil fertilizers  help to maintain the soil fertility and  improve  plants  growth.

5. Minerals  are Important  Nutrients :

Our  body needs  minerals  like  sodium, potassium, calcium, zinc and iron in small quantities , for health growth  Need to Conserve  natural resources Coal and petroleum are very  useful natural resources  of energy. The consumption of  these  fuels  is increasing  day  by day due to large numeber  of vehicles  and industries , however , these  is  a limited  amount  of these  resources on the earth. Once  these  resource used  up, they will not be available  again. also burning  of these  fuels  release  harmful gases , in the atmosphere  causing  air pollution which is  the  biggest heals  hazard 

Judicious and economical use  of these resources  can help us  to conserve  them and  prevent  pollution. we should  conserve  these fuelsd  by using  alernate  resources  of energyt like  solar  enerfy, wind , energy. These are unlimited  and do not cause  pollution .

States of matter solid liquid and Gases

States of matter solid liquid and Gases

All things, whether living or non-living, are made of matter. Anything that has mass and occupies space is called matter. Table, chair, water, milk, air, etc., are matter. matter is made up of very small particles called molecules. on the bases of arrangement of molecules, matter exists in three states-- solid, liquid and gas.

ARRANGEMENT OF MOLECULES

Solids: In solids, molecule;es are very closely packed. there is a strong force of attraction between them. They cannot move away from one another. So, solids are hard, rigid, have fixed shape and volume, and cannot flow.

Liquids: In liquids, the molecules are not very close to one another due to weak force of attraction between them. So, the molecules in liquids can move and slide over each other. This makes liquids flow. Liquids take the shape of the container in which they are poured into. So, liquids do not have a fixed shape but have a fixed volume.

Gases: In gases, the force of attraction between the molecules is the weakest. So the molecules in gases  are far apart from one another and they are free to move. This makes the gases flow easily and fill the container completely in which they are kept. So, gases neither have a fixed shape nor a fixed volume.

CHANGE OF STATE

In previous classes, you have learnt that the state of matter can be changed from one form to another on heating or cooling. Do you know how this happens? Do you know how this happens? Let's see the effect of heating or cooling on the molecules of matter.

EVAPORATION

The change of a liquid into gaseous state on heating is called evaporation. When water is heated, it changes into water vapour. This is because, on heating, water molecules start moving faster. they become free and escape into the air in the form of water vapor and can move much more freely.

Condensation 

When steam gets cooled, it condenses to form water again. This happens because on cooling steam, the movement of water molecules becomes slower. They start moving close to one another. They become less free to move and thus come closer to one another to form water. The change of a gas into liquid state on cooling is called condensation.

Melting 

Ice is solid. When it is kept at a warm place, the movement of molecules of ice increases. They become free from the rigid form and thus become loosely packed and form water. The change of a solid into liquid state on heating is called melting.

Freezing

When you cool water, the movement of its molecules slows down. They come very close to one another and pack into a rigid shape to form ice. The change of a liquid into solid state on cooling is called freezing.

SOLIDS IN WATER

Take a glass of water. Add a few crystals of sugar in it and stir. You find that the particles of sugar disappear. Where have the sugar particles gone? The particles of sugar take up the space between the molecules of water. So, we say that sugar gets dissolved in water.

LIQUIDS IN WATER

You must have seen a painter removing paint from his hand by using turpentine oil, not with water. This is because paint gets dissolved in turpentine oil and is easily removed, whereas it does not dissolve in water.

Some liquids when mixed together dissolve in each other. They are called miscible liquids. For example, liquids like glycerine and milk dissolve in water. Some liquids when mixed together do not dissolve in each other. They are called immiscible liquids. For example, kerosene iol and vegetable oil do not dissolve in water.

GASES IN WATER

When you boil water, you observe some bubbles are formed along the sides of the vessel. These are the dissolved gases that get separated from water on heating. Gases like carbon dioxide, oxygen and nitrogen dissolve in water. For example, water in rivers, oceans and lakes has oxygen dissolved in it. When we open a bottle of aerated drink, bubbles of carbon dioxide gas come out. Carbon dioxide gas is dissolved in water under great pressure.

EXPANSION AND CONTRACTION OF MATTER

When we heat a substance, its size increases. This increase in size of matter is called expansion of matter. On heating, s substance expands or its size increases because the movement of molecules increases and the space between them also increase.

For example, to open a tight metal lid of a jar, we dip it into hot water because the heat of water expands the lid a little and it opens out easily.

When we cool a substance, its size decreases. This decrease in size of matter is called contraction of matter. On cooling, a substance contracts or its size decreases because space between them decreases. That is why, electric cables do not appear loose in winter, while they hand loosely from poles in summer.

PHYSICAL AND CHEMICAL CHANGES

1. Physical Change

When the change occurs only in the shape, size and state of matter, it is called a physical change. It is a temporary change and can be reversed. No new substance is formed during this change.

Physical change may occur due to heating and cooling. For example, when you heat water, it changes into steam. On cooling steam, it changes again into water. Similarly, when you freeze water, it changes into ice. Stretching of a rubber band is also a physical change.

 

2  Chemical Change

When matter changes altogether to form a new substance, it is called a chemical change. It is a permanent change and cannot be reversed. For example, burning of paper. When we burn paper, it changes into a completely new substance called ash and we cannot get back the paper.

Styrene Gas Hazards

Styrene(Polystyrene)  Gas  Hazards 

Styrene is  a colorless liquid  that has  a sweet smell  that evaporate  easily  in its pur form, styrene has sweet smell, Manufactured  styrene may contain aldehyde , which give it a sharp unpleasant  odor Large amounts  of styrene  are produces in the united states . small amount  are produced naturally bt plants , bacteria , and fungi . Styrene is also present in combustion products such as Cigarette  smoke  and automobile  exhaust .

styrene is widely used to make plastics and rubber . Consumption product  containing styrene include 

1.Packing materials 

2.Insulation for electrical uses 

Breakdown of  styrene  : Styrne  is quickly broken down in the air  usually  within 1.2 days

 Long term exposure  to styrene   can cause  following Effect :

• Central nervous system and kidney effect.
• Headaches 
• Depression 
• fatigue  and weakness
•  Hearing  loss
•  Balance and concentration problems
• cancer 

Force , work and Energy

Force  , work and energy

 To move anything , we  either pull it or push it  when e  play cricket ,  , We push the  ball with the bat . During cycling  we push the pedals  of the  cycles  to move  it . To open a door , we  either  push it .

A push or pull on an object is called force

Some  other  examples  of push or pull are shone in the picture  given along side

A force does not move  an object  always  for examples , if we  apply force  on a wall, it does not move .

 Effect of force

 Force can affect an object in many ways . Let us learn about these effects

 1.Force can stop a moving object  in opposite direction, the objects  shows or stops   for examples  force   applied  by a player  on moving  football, stop it

2. Force can move a stationary object

 When you apply force on a stationary objects , it moves  the objects  in the direction of  applied  force . For examples, a player moves  a football; by kicking  it .

 3.Force can change the direction of moving objects

 We apply force on the steering wheel to change the direction of moving  car

 4.Force can change the shape of the  an object

 When you presents  an inflated  balloon full of air , its  shape changes when you make  chapattis , the force  applied  by your  hand  changes the shape of the dough

 Types of force

Magnetic force

 When you bring  a magnet near iron nails , it attracts  the nails . The  force applied  by a magnet  on an objects  is called  magnetic  force

Electrostatic force :

 When you comb your dry hair and bring the comb near tiny bits  of paper , the paper gets attracted  towards  the comb. This  is  because  on  rubbing m, the  comb gets  charged  and attracted  tiny bits  of paper . so when things  are rubbed  with each other , they become  charged  and force of attraction is produced . this force of attraction  is called  electrostatic  force .

Gravity or Gravitational force

Every things that you through up in the air , comes  down, ripe  fruit s always  fall on the  earth’s  from a tree. You cannot jump beyond a certain height. Do you know why? Our earths exerts a force on every objects, that attracts  the object towards  its centre . This  force is called  gravity or Gravitational force

 

Force  of  friction :

 When we roll a ball on the floor , it  gradually  slows  down and finally stops . in the same  way , even you stop  paddling  you cycle, it gradually  slow does not  and stops. Why does ball or cycles stop[s?  they stop because  a force  acts between  the  ball or cycles  and  the floor  that slow down the ball or cycles . this force is called  frictional fore or  force of friction. A force  that slows down the movement of an objects  on a surface  is called  force of friction or frictional force .

Advantages of friction

 It helps us  to walk. We can not walk easily on a road  very smooth surface  or wet  floor  because there  is very less  friction and we  may slip on the floor

 Friction between road  and tyres of automobiles  makes  their movement possible

 You are able  to write  with your pen because  of friction. You often see that you cannot write  easily on oily paper . this  is because  there is very less friction  between our  pen and oily paper

Friction also helps to erase pencils marks from  the paper  by using  an eraser

Disadvantage of  friction :

 It slow down or stops the motion of an objects

Friction produce  heat that damage  the machine s . That is why we  use oil in sewing  machines cycles , etc

Friction damage the  tyres of  vehicles  and  soles  of our shoes

 Work Ram is reading  a book. Anuj is pulling  a toy car. Now  tells  who is doing  work? Anuj is doing  work Surprised ! in Science ,  work is said  to be done  only when  force  change s the position of an objects . Anuj is applying  force  to mover  the toy car . Car is changing  its position. So he is  doing  work. Thus  work is said  to be  done  only when the applied  force  change s the  position of the objects . for  Example s, when  you push a  table  and it moves , then work is done . when you push an almirah with all the force  you have , there is no change  in its position. Then, no work is done .

Energy :

The ability  to do work is called  energy . to perform any activity like  playing , reading , and sleeping , we need  need  energy ,even machines  need  energy  to work 

 

Types of energy :

1.Heat energy: Energy that we get from heat is called heat energy. This energy is produced by burning fuels, like coal LPG and Kerosene. we use  heat energy to cook food .

2. Light energy: Energy that we  get from  light  is called  light  energy . It is produced by bulb, CFL(Compact fluorescent  lamp) candles  etc. We  are able to  see  with the help[ of light  energy.

3.Kinetic Energy: The energy of  an objects  due to its movement is called  kinetic energy.  A moving  bus, moving  cycles, running  boy , etc , have  kinetic energy.

4.Potential energy:

The Energy stored  in an objects  due  to its  position is called  potential energy. The  water  stored  in a  tank on the roof  has potential energy because  it is stored  at a height .

5.Mechanical energy: The energy in an object due  to its  position (( potential energy ) and  its movement (( Kinetic energy ) is called  mechanical energy. The water stored behind a dam in the reservoir  has  potential energy that changes  into kinetic energy when the water fall down from a 

 certain height .

6.Electrical energy: The energy that we  get  from electric current  is called  electrical energy it ios used to ru  electrical appliance  like  television and washing  machine . it is  generated  at power station and supplied  to our homes 

7.Wind energy : The energy  that we  get  from the wind (morning air ) is called  wind energy . It is used  to generate  electricity by using  a windmills

8.Solar energy: The energy of the  sun is called  solar energy. It is used  to cook food in solar  cookers , to heat water  in solar heater , etc . It is also used  in solar calculator  and  solar watches

9.Hydro energy: The energy of the flowing  water  generates  electricity in hydroelectric power  plants . The  electric  energy so generated is called  hydroelectricity

 

 

Simple Machine and Compound Machines

Simple Machine and Compound Machines

A simple machine is a device  that makes our work  easier and faster .Scissors, knives, tweezers and  tongs  are some example  of simple machine .

Simple machine are of different  types leavers , pulley , inclined plane ,screw, wheel and axle and  wedge.

 

Lever 

 You must have seen that we  can easily open the  the  tin cap of soft drink bottle  using a bottle - opener. similarly we can lift heavy objects  using a rod . The bottle opener  and  the rod  are examples of lever 

A simple machine  that turns around a fixed point is called  a lever .

a lever helps us to do more work by applying less force  . this makes our work easier . the Terms  related  to a lever  are - Load, effect and fulcrum.  

1. The  Object on  which work is  to be performed is called load (L)

2. The force applied on a lever to lift( or move) the load is called effect (E)

3. The fixed point on which a lever turns is called fulcrum( F) 

Classes of levers 

There  are mainly three classes  of levers depending on the potions of the load (L), effort (E) and fulcrum(F)

1.First class lever : in first class lever , fulcrum is in between the load and  effort. Some examples of this type of lever are  crowbar , See-saw , scissor, spoon, etc. 

2. Second -class lever : in Second class levers load is in between the  fulcrum and effort. some examples of second - class lever are wheel- barrow, nut cracker , Bottle cap- opener , etc

3. third -class lever : in third- class levers , the effort is in between the fulcrum and load. Some examples of third- class levers are  forces, ice  tongs, knife , staple  machine , etc

 Pulley 

it is difficult;t to lift  a bucket full of water  from a well but you can do this easily when you use pulley. A pulley consists of a particular disc made of metal or wood with a groove  cut along its  rim. A  rope passes around the  groove  prevents the rope from slipping off the disc. the pulley rotates about  an axle fixed to a support .Inclined Plane 

 A simple machine trhat has a sloping  surface is called an inclined  plane. some examples of inclined plane are ramps sloping wooden planks , Slides , etc . Inc;lined  planes are provided  in the hospitals so that wheel chairs carrying  patients can easily be pushed .

Screw 

A screw looks like a nail with groove cut into . it . It has a winding  edge called thread. To insert a screw  in a wood , it is screws in by turning  it round  and round  with screw - driver . Less force  is needed to insert  a screw  in the  wood  than the nail. The srew  can hold  things  together  tightly. A screw jack is an examples  of a screw   .

Wheel and Axle

Each time  you turn the knob of  your water tap or the door  knob of  your house, you are using a simple machine , that is , a wheel and axle. A wheel with a road attached to it is called a wheel and  axle arrangement .

When we  turn the wheel, the axle  also turns . in a  screw driver , trhe thick handle  works a  the wheel and the  thinner  metals rod as the axle. With this arrangement , it tkes less force  to move  something . other examples  of wheel and  axle are the steering  wheel of a car and  a drill used  by carpenters

Wedge

 It is a  V- shaped  piece, generally made of metal. It has two inclined planes  put together  to form a sharp  edge. a blade , an axe  and knife  are examples  of wedge. It is used to cut  and split things 

Compound Machine

When you open up a clock, you find several simple machines inside it . Similarly , the cars, aeroplanes, sieving  machines  also . consist of several simple machines.

Machine that consist of  several simple  machines s are called  complex  machine  or  com,pound  machines .

 Machines  have made our  life  simple . We  must take  care  of machines and maintain them property .