St.John High SchoolFort, Bellary

Submitted ByVishwadeep

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Periodic Classification of Elements

Science Project

Biology&

Chemistry

•Dmitri Ivanovich

Mendeleev:

•Born on 8 February 1834 – 2 February

1907 O.S. 27 January 1834 – 20

January 1907) was a

Russian chemist and inventor.

•He formulated the Periodic Law,

created his own version of the periodic

table ofelements, and used it to correct

the properties of some already

discovered elements and also to predict

the properties of eight elements yet to

be discovered.

S I L I C O NSilicon is a chemical element with symbol Si and atomic number 14. It is

atetravalent metalloid, less reactive than its chemical analog carbon,

thenonmetal directly above it in the periodic table, but more reactive

thangermanium, the metalloid directly below it in the table. Controversy

about silicon's character dates to its discovery; it was first prepared and

characterized in pure form in 1823. In 1808, it was given the name silicium

(from Latin: silex, hard stone or flint), with an -ium word-ending to suggest

a metal, a name which the element retains in several non-English

languages. However, its final English name, first suggested in 1817,

reflects the more physically similar elements carbon and boron.

Silicon is the eighth most common element in the universe by mass, but

very rarely occurs as the pure free element in nature. It is most widely

distributed industs, sands, planetoids, and planets as various forms

of silicon dioxide (silica) or silicates. Over 90% of the Earth's crust is

composed of silicate minerals, making silicon the second most abundant

element in the Earth's crust (about 28% by mass) after oxygen.[7]

Appearance

Diatoms can form small colonies, and filaments have been seen to measure over two feet. The size of these very diverse micro-organisms varies greatly. There is a yellow tint that can be seen due to photosynthetic plastids. When observed as larger masses, the color takes on a darker color, often deep brown or black. Some diatoms also have a blue or green color, but these are the exceptions. HabitatDiatoms are found in both fresh water and salt water. There in

fresh water habitats mostly in the spring and fall months. Not

only do diatoms live in streams, lakes and other bodies of fresh

water, but they can be found on the rocks, plants, and mud that

is nearby or at the borders of the water.

GREEN PLANTS AND CHORDATES

The Plant body is

called Thallus. The

cells are typically

eukaryotic, with a

prominent nucleus and

many plastids. The

cellwall is composed

of Cellulose and pectin.

In green Algae, Green

Pigment Chlorophyll is

maximum. Eg. Spirogya

and Ulothrix. In Red

Algade in additional to

Chlorophylla red

pigment called

PHYCOERTHRIN.

Byrophytes includes two groups of Plants namely Liverworts and Mosses. Liverwors have a green plant body resembling the shape of liver. Eg. Riccia, Marchantia. In Mosses the plat body grows vertical to the soil surface.Eg : Polytrichum, Funaria.

Bryophtes reproduce sexually. The Life Cycle includes two generations vizGametophyte and a Diplooid Sporophyte. The adult plant body is called Gametophyte. Since it produces male and female games in distinct structures called antheridia and Archegonia respectively. Gametophyte is photosynthetic and can lead an independent life. The Zygote resulting from sexual reproduction develops into a diploid sporophyte.

Pteridophytes or Pteridophyta, in the broad

interpretation of the term (or sensu lato),

are vascular plants (plants

withxylem and phloem) that reproduce

and disperse via spores. Because they

produce neither flowers nor seeds, they are

referred to as cryptogams. The group

includes ferns, horsetails, clubmosses, spike

mosses and quillworts. These do not form

a monophyletic group, because ferns and

horsetails are more closely related to seed

plants than to lycophytes(clubmosses,

spikemosses and quillworts). Therefore,

pteridophytes are no longer considered to

form a valid taxon, but the term is still used as

an informal way to refer to ferns

(monilophytes) and lycophytes, and some

recent authors have used the term to refer

strictly to the monilophytes.

The flowering plants (angiosperms), also known

as Angiospermae Lindl.[2][3] orMagnoliophyta, are

the most diverse group of land plants.

Angiosperms are seed-producing plants like

the gymnosperms and can be distinguished from

the gymnosperms

by characteristics including flowers, endosperm wit

hin the seeds, and the production of fruits that

contain the seeds.

Etymologically, angiosperm means a plant that

produces seeds within an enclosure, in other

words a fruiting plant.

The ancestors of flowering plants diverged

from gymnosperms around 245–202 million years

ago, and the first flowering plants known to exist

are from 160 million years ago. They diversified

enormously during the Lower Cretaceous and

became widespread around 120 million years ago,

but replaced conifers as the dominant trees only

around 60–100 million years ago.

ANGIOPHERMS

In the 1750's, Carl Linnaeus, a Swedish scientist who decribed many North American birds,

established a system or hierarchy of living organisms so that scientists all over the world could

understand each other. Since then, the Linnaeus System has been improved by a number of

scientists and it's still being changed today as new discoveries are made among groups of birds.

The science of naming things, such as birds, is called "Taxonomy" and it can become quite

complicated, but the basics are easy to understand.

Basics of Taxonomy:

All living organisms are divided into 5 Kingdoms: Plants, Fungi, Animals, Protoctista and Bacteria

(the last two have to be seen through a microscope). The living members of the Animal (Animalia)

Kingdom is divided into smaller groups called Phyla (singular) or Phylum (plural) which means a

direct line of descent within a group and then its further divided into smaller groups called Classes.

Classes are divided into even smaller (though still fairly large) groups called Orders. After

categorizing the Orders, we have Families and sometimes Subfamilies. Within each

Family/Subfamily, there are are number of Genera (plural for Genus) and within each Genus are a

number of Species.

A White-breasted Nuthatch can then be classified as:

Kingdom: Animalia

Phylum: Chordata

Class: Aves

Order: Passeriformes

Family: Sittidae

Genus: Sitta

Species: carolinensis

Manufacture of glass

The manufacture of glass involves the following steps:1. Limestone, sand and soda ash are mixed and poured into a tank furnace. Tankfurnace looks like a small swimming pool. It is very hot (about 17000C). It isshallow at one end and deep at the other.2. The raw material moves slowly towards the deeper end. Silica melts at a veryhigh temperature. In order to lower its melting point, soda ash is added. Thus,energy is saved and a low cost is incurred in the glass-making process.3. Due to the presence of limestone, glass becomes insoluble in water.4. As the raw material melts, a clear jelly-like substance is formed; this takes about a week’s time.5. During this time bubbles of CO2 gas escape and some of the raw material slowly changes into a mixture of silicates.6. The following reactions take place inside the furnace.7. The clear jelly-like substance on cooling sets to form glass. This is known as soda-lime glass.

Types of glassThere are nine types of glass according to the minor additions and variations inthe ingredients used and according to the methods of manufacturing. Thedifferent types of glasses are different in their properties and uses.

1. Soda glass or soda-lime glass:

It is the most common variety of glass. It is prepared by heating sodiumcarbonate and silica. It is used for making windowpanes, tableware, bottles andbulbs.

2. Coloured glass:

Small amounts of metallic oxides are mixed with the hot molten mixture of sand,sodium carbonate and limestone. The desired colour determines the choice ofthe metallic oxide to be added, as different metallic oxides give different coloursto the glass.Coloured glass is much in demand. It is used for decorating walls, makingsunglasses, and for making light signals for automobiles, trains and aeroplanes.

3. Plate glass:Plate glass is thicker than ordinary glass. It has a very smooth surface. It is made byfloating a layer of molten glass over a layer of molten tin. It is used in shopwindows and doors.

4. Safety glass:It can also be called shatterproof glass. It is made by placing a sheet of plastic suchas celluloid between sheets of glass. The special quality of this glass is that in caseof breakage the broken pieces stick to the plastic and do not fly off. You must havenoticed a broken window-pane of a bus or a car still in its place. It is used inautomobiles. It is also used for making bulletproof screens.

5. Laminated glass:It can also be called bulletproof glass. Several layers of safety glass are boundtogether with a transparent adhesive. The larger the number of layers used thegreater is the strength of the glass. It is stronger than safety glass. It is used inaeroplanes and windshields of cars.6. Optical glass:Optical glass is softer than any other glass. It is clear and transparent. Potassiumand lead silicates are used in making optical glass. It is also called flint glass. Themain use of flint glass is in the manufacture of lenses, prisms and other opticalinstruments.

9. Lead crystal glass:

Lead crystal glass has high refractive index, and so has the maximumbrilliance. It sparkles and is used for high quality art objects and forexpensive glassware. It is also called cut glass because the surface ofthe glass objects is often cut into decorative patterns to reflect light. Inorder to increase the refractive index, lead oxide is used as flux incrystal glass, therefore it is also called lead crystal glass.

The major disadvantage of ordinary glass is that it is brittle. It crackswhen subjected to sudden changes of temperature. When the glasshas been moulded into a finished article, it is cooled very slowly toprevent brittleness. The process in which a finished glass article iscooled slowly is called annealing.