Physical World

                     Physical World and its Measurements(Part-3)

Dimensions

                      The Dimensions of a physical quantity to which the units of base quantity are raised to represent a Drive Unit of a quantity.

Some physical quantities with there dimensional equations:

 

1)Area- Length x breath

            =L x L=L2

            =[M0L2T0]

2)Volume- Length x breath x height

            =L x L x L =L3

            =[M0L3T0]

3)Velocity-Displacement

                        Time

                 =m  =L   =LT-1  =[M0L1T-1]

                    s    T

4)Acceleration- Velocity

                              Time

                   =         Distance      =m  =  L    =LT-2   =[M0L1T-2]

                          Time x Time      s2     T2

5)Force-Mass x Acceleration

              Mass x  Velocity 

                             Time

           

              Mass x      Distance

                             Time xTime

               Mass x M   =   m x L     = m x LT-2    =  [M1L1T-2]

                           T2               T2

Physical World

                  Physical World and it's Measurements(Part-2)

System of units

                            There are various of system of units and which are as follow:- 

     1)E.P.S.:In this system of measurements the length is measured in foot, weight is measured in             pound and time is measured in second. 

     2)C.G.S.:In this system of measurements the length is measured in centimetre, the weight is               measured in gram and the time is measured in second.

     3)M.K.S.:In this system of measurements the length is measured in metre, weight is measured in       kilogram and time in second.

     4)S.I. system(International system):This system of measurements is used by all the countries at       international level. 

List of fundamental units

     S.No.               Physical quantity                 Fundamental Units              Symbols

       1)                             Mass                                                  Kilogram                           Kg 

       

       2)                            Length                                                   Metre                               M   

       3)                             Time                                                    Second                              S  

       4)                       Temperature                                               Kelvin                              K

       5)                     Electric Current                                           Ampere                             A

       6)                   Luminous Intensity                                       Candela                            Cd

       7)                    Quantity of Matter                                         Mole                               M

List of Some Drive Units

    S.No.               Physical Quantity                      Drive Units                       Symbols

      1)                             Force                                                 Newtone                               N 

      2)                            Energy                                                  Joule                                   J

      3)                             Power                                                  Weight                               W 

continued in part 3.........         

Reproduction in Plants

                                          Reproduction

• In reproduction a living organism give rise  a new offspring which is similar to it.
• The nucleus of the cell contain DNA (Deoxyribose nucleic acid) which is the heredity material.
• DNA is able to replicate and it forms new cells causing variations,that's the reason of cells genetically similar but identically not.
• Variation is necessary for the evolution and the survival of the species over time.

Types of reproduction  

 Asexual reproduction:

• In asexual reproduction a single individual participate and produced a new individual without the involvement of  gametes and new individual is identically similar (clone) to the parent.
• Asexual reproduction is a rapid reproduction as compared to sexual reproduction and it is mainly adopted by lower plants.

Sexual reproduction:

• In sexual reproduction two individual participate (with opposite sex) and give rise to a new individual with the involvement of male and female gametes fusion.
• In sexual reproduction the new individual is genetically similar but identically not. 

Modes of Asexual reproduction

1. Fission:It means breaking.In this method parent cell divides into two or more daughter cells. There are two types of it a)Binary fission and b)Multiple fission.
2. Fragmentation:In this method a organism breaks-up into small small pieces which are called fragments and each fragment develops into a new individual e.g. Spirogyra.
3. Regeneration:In regeneration if a organism get cut into pieces,each piece of the organism grow and develop into a complete organism e.g. Planaria.
4. Budding:In budding a bud is develop on a small outgrowth surface of the parent which get detached at the time of complete development (till that all the nutrition the bud take from the parent e.g. Hydra.
5. Vegetative propagation:In this method new plants develops from the vegetative parts.It is mainly divided in two types first Natural and second is Artificial.

     

          Natural:

       a)By roots e.g. sweet potato.

      b)By stem e.g. potato,ginger.

     c)By leaves e.g. bryophyllum.

          Artificial:

         a)Grafting e.g. mango.

        b)Cutting e.g. rose.

       c)Layering e.g. jasmine. 

      d)Tissue culture e.g. orchid

     Some benefits of tissue culture

                               With the help of this method we can grow those plants who lost their capacity to produce seeds like banana, rose and jasmine etc.And these plants are genetically similar to the parents.

      6.Spore formation:These are small structure which are covered by thick hard wall.Spores germinate only in favourable condition till than they are protected by theid thick hard wall.

Physical World

                       Physical World and Measurements

Welcome to the first topic of the Physics.In this topic we learn some basic and important definations and we learn how to find dimensions with  the help of basic old formulas.

What is Science ? 

                                 "Science is a system of knowledge in which we gain our knowledge through observations by systematically arrangement".Science involves in our all daily activities like walking,standing,eating and sleeping.

What is Physics ?

                                    "Physics is the branch of science which deals with the study of nature,matter and nature phenomenon.E.g. light,energy,radiation,sound and magnetism etc."

There are some important parts of physics which are:- 

• Measurements:The measurement is the process of comparison of unknown quantity with a known quantity.

• Mass:The mass of the body is defined as the quantity of matter in the body.The mass of the body cannot be zero or negative.It always positive.

• Length:Length of an object may be deffined as the distance of separation between any two points at the extrements of the objects.

• Time:Time is something what a clock reads.

• Fundamental Units:Fundamental units are those units which don't depends upon any other physical quantity.E.g.Mass Time and Length etc.

• Drive Units:These units are those units which depend upon the fundamental units.E.g. Velocity Force and Pressure etc.

      continued in second part................

Anatomy of Flowering Plants: Sclerenchyma tissues

                                                                   SCLERENCHYMA

Now the third or the final simple tissues of the flowering plants which is sclerenchyma tissues.
These tissues basically protect or provide the machenical support to the higher plants.

                                                               Fig.Sclerenchyma

Important points to remember are:-

1)They consists of long,narrow cells with thick and lignified cell walls having a few or numerous pits.

2)The sclerenchyma cells are usually dead and without the protoplasts.It means the protoplasts of these cells die and as we learn above they protect or provide support that's the reason they didn't need protoplasts.

3)Structure of these cells are thick-walled,elongated and pointed cells,generally occuring in groups in various parts of the plants.

4)As we seen in the figure there is sclereid which are spherical, oval or cylindrical highly tkickened dead cells with narrow cavities.These are commonly found in the fruit walls of nuts.

end of the simple cells topic in plants....