Characteristics of particles of matter

Characteristics of particles of matter:

1.      Very small in size.

2.      Have spaces between them

3.      Particles are constantly moving

4.      Particles attract each other

The characteristics of particles can be discussed by experiment.

Particle of matter are very small: we take a beaker full of water and add small amount of ink to it. Ink diffuse in water and spreads uniformly. When more water is added the colour dilutes, this is because few drop of ink is composed of millions of small particles which keep on spreading in large amount of water. 

Particles have space between them: we take a beaker full of water and add small amount of ink to it. Ink spreads uniformly between the spaces present between the particles of water.

Particles are constantly moving: we take a beaker full of water and add small amount of ink to it. Ink spreads uniformly after some time even when we leave it undisturbed, this happens because the particles of matter are constantly moving. The same can be observed with essence sticks, as the gases spread from one corner of room to the whole space.

Particle of matter attract each other: the force of attraction between the particles of same matter is called cohesion. This cohesion is different for different material. Like for liquid and gases they are less but for solid they are large. That is why it is difficult to break apart a solid but it is easier of liquids. We can move our hand through liquid and gases but not through solid. We cannot break iron but ban easily break chalk as cohesive force between the particles of iron is much larger than that of chalk.

  

Matter is made of particles

Every matter is made up of very small particles. These tiny particles are extremely small which cannot be seen even with high power microscope. These small particles that form other objects are called atoms and molecules.

How to prove that matter is made up of small particles.

We can easily observe that matter is composed of small particles by mixing two different things and noticing the two dissolve in each other.

1.      Dissolving solid in liquid

2.      Dissolving liquid in liquid

3.      Mixing two gases

Dissolving solid in liquid: To discuss this we will take

 Potassium permanganate, a purple coloured solid crystalline substance and water, a colourless liquid. When potassium permanganate is added to beaker full of water and leave it as it is, slowly the colour of water will change to purple, this is because the molecules of potassium permanganate separate from one another and diffuse in water. Here diffusion means that the molecules of potassium permanganate spread in water to make a uniform solution.

Dissolving liquid in liquid: To discuss this we will take

 Blue coloured ink and water. When ink is added to beaker full of water and leave it as it is, slowly the colour of water will change to blue, and this is because the molecules of ink diffuse in water. This means that ink and water both are made of small particles.

Mixing two gases: let’s take 2 test tube

One with colourless gas and other with bromine vapour, a red-brown coloured gas when the two test tubes are joined after some time the content of both gases mix with each other. Content of both tubes are made of small particles that diffuse in each other

This diffusion phenomenon gives us two conclusions:

1.      Matter is made of two particles.

2.      These particles have kinetic energy and they are constantly moving.

Matter is made of particles

Matter is made of particles

Every matter is made up of very small particles. These tiny particles are extremely small which cannot be seen even with high power microscope. These small particles that form other objects are called atoms and molecules.

How to prove that matter is made up of small particles.

We can easily observe that matter is composed of small particles by mixing two different things and noticing the two dissolve in each other.

1.      Dissolving solid in liquid

2.      Dissolving liquid in liquid

3.      Mixing two gases

Dissolving solid in liquid: To discuss this we will take

 Potassium permanganate, a purple coloured solid crystalline substance and water, a colourless liquid. When potassium permanganate is added to beaker full of water and leave it as it is, slowly the colour of water will change to purple, this is because the molecules of potassium permanganate separate from one another and diffuse in water. Here diffusion means that the molecules of potassium permanganate spread in water to make a uniform solution.

Dissolving liquid in liquid: To discuss this we will take

 Blue coloured ink and water. When ink is added to beaker full of water and leave it as it is, slowly the colour of water will change to blue, and this is because the molecules of ink diffuse in water. This means that ink and water both are made of small particles.

Mixing two gases: let’s take 2 test tube

One with colourless gas and other with bromine vapour, a red-brown coloured gas when the two test tubes are joined after some time the content of both gases mix with each other. Content of both tubes are made of small particles that diffuse in each other

This diffusion phenomenon gives us two conclusions:

1.      Matter is made of two particles.

2.      These particles have kinetic energy and they are constantly moving.

States of matter

Three states of matter

Now we will discuss the three states of matter : solid, liquid and gas.

Properties of solid:

·         Fixed shape and volume

·         Have high density

·         Do no flow

·         Certain solid can be compressed but not much, eg rubber

Properties of liquid:

·         Have fixed volume but don’t have a ffixed shape

·         They have less density than solid

·         Flow easily

·         Cannot be compressed

Properties of gases:

·         Have no fixed shape or volume

·         Have very low density

·         Flow easily

·         Can be compressed easily

Comparing the properties of solid, liquid and gases

Shape: either it is a book, chair or table every solid have a fixed shape, their shape remains the same wherever we place it. But in case of liquid and gases they do not have a fixed shape because they change their shape according to the container in which they are stored

Volume: solid and liquid have fixed volume, that means that they will occupy a certain required space, a iron ball of volume 100cubic cm when melted and moulded in another shape will still occupy the same space, similarly when 1l of water when kept in a jar or in a tub may change its shape but in both cases it will occupy same 1l of space. In case of gases the gas can be compressed in a small space by applying pressure, LPG and CNG is an example of large amount of gas compressed in small cylinders.

Density: density of solid is maximum, liquid has comparatively less density and gases have even more density. This difference in density is due to gap in molecules of atoms, the atomic gap in case of solid is negligible. They are very closely packed and hence the density is high, the molecules of liquid are comparatively far with each other and gases are even farther so the density of liquid are less and gases even more less.

Flow: the flow of solid is zero, this means that solid cannot flow, this is because they have a defined shape, their molecules are compact without any gap between them, they have high force of attraction among their molecules which keep them from flowing. But in case of liquid and gases they have a defined shape, their molecules are less compact means they are a bit far and the force of attraction between their molecules are less so they can easily flow. Due to these factors gases can flow even more easily when compared to liquids.

Compression: there are a few solids like rubber and sponge that can be compressed under pressure, rubber is elastic in nature so it can change its shape when force is applied, on the other hand sponge has minute pores from which air gets squeezed out when we press it thus changing its shape. Liquid cannot be compressed although it has space between its molecules, gases have lots of space between them so when compressed  they gets squeezed and decrease in volume.

Why salt, elastic and sponge are called solid?

Although when placed in a container salt and sugar take their shape but the single particle of salt have its definite shape which cannot be changed.

Rubber is elastic in nature so it can change its shape when force is applied on it

Sponge has minute pores from which air gets squeezed out when we press it thus changing its shape.

Matter: An introduction

What is matter?

Anything that has volume and mass is called matter. Substance either as light as a feather or as hard as a brick all are matter. Anything which can flow as water or smoke all are matter.

Oxygen and hydrogen are gases, they have volume and mass which is negligible. Water, milk or juice have mass and they occupy space. Sand or brick they have mass as well as they occupy space.

All these are matter.

When we look around us everything that we see is matter. In the morning from using toothbrush till the night while we go in our beds all are matter.

                                                            

On the basis of physical properties matter is classified in three forms: Solid, liquid and gas

Solids are those substance which have fixed shape and volume.

Liquid are those substance which have fixed volume but no fixed shape.

gases are those substance which have no fixed shape and volume.

On the basis of chemical properties matter is classified in three forms: elements, compound and mixtures

Elements : these are the substance in simplest naturally occurring form. These substance cannot be further split in more simpler form using any chemical method.

Elements can be further divided as metal, non-metal and metalloid.

Metal are the strong elements(have high tensile strength) that are good conductor of electricity. They are malleable, ductile and lustrous. They have high density and sonorous.

Non-metal are low tensile strength element that do not conduct electricity. They are brittle and have low melting and boiling point.

Metalloids are the elements that show some properties of metal and some properties of non-metal.

Compounds are substance made up of two or more elements chemically combined in a fixed ratio.

Mixture is a substance that is made up of two or more elements physically combined. mixtures are of two types: homogenous mixture and heterogenous mixtue

Homogenous mixture: this type of mixture have their components uniformly mixed with each other. The components cannot be distinguished.

Heterogeneous mixture: those mixture in which one substance remain separate and can be distinguished from the rest of components are heterogenous mixture.

Gland and reproductive system

Glands and hormones

Glands are those cells which produce secretion called hormones that are released in the blood stream to reach their target sites

Hormones are the chemical messenger that travel inside our body through blood stream and control our body to function and perform its day to day activity.

Glands are divided in two types: endocrine glands and exocrine glands

Endocrine glands: these glands are ductless glands that mean that they pour their secretion directly in the blood stream. The secretion reaches its target site travelling through blood. Eg; pineal, pituitary, parathyroid, thyroid, thymus, adrenal, ovaries(female), testes(male).

Exocrine glands: these glands release their secretion with the help of duct at the specific sites. Eg; tear gland(lachrymal), salivary, mammary(female), live,r intestinal, urethral(male).

Heterocrine glands: these are the exceptional gland which poses both kinds of characteristics. Some secretions are released through duct while some secretions are released directly in the blood stream. Eg; pancreas and gonads.

What is the role of hormone is initiating reproductive system?

When the pituitary gland also called as master gland secrete follicle stimulating hormone (FSH), it stimulates the gonads (testes and ovary) to release testosterone and estrogen respectively. These hormones cause the physical change in human body to take place. Along with this testosterone and estrogen activates the testes and ovary to release their respective gametes, sperm and ova.

Reproductive phase in life of humans:

Reproductive phase in the life of a female: in female the reproductive phase starts at puberty with the time when the ovary releases it first ova and it lasts till the age of 45-50 years. With the onset of puberty ova start to mature. During the reproductive period the two ovaries start to release ova after each 28 days. Each ovary release an ovum alternately at the difference of 28 days. When the ovum is released it passes through the fallopian tube, during this period the uterus prepares itself for the situation in which egg gets fertilized and zygote is formed. In the presence of estrogen and progesterone the wall of uterus gets thick and gets enriched with lots of capillaries. This happens because the foetus settles in the uterus and the foetus gets nutirition from the mothers blood through the umbical cord. If there is no fertilization the uterus wall slowly breaks down and blood and mucous is released from the vagina. This process is called menstruation and it repeats at every 28 days in the form of a cycle.

Sex determination of boy or a girl

The genetic information of a person is carried in the nucleus of its cell. In the nucleus the information is present in the chromosomes in the form of genes. Genes carry the information from parents to offsprings. Sex chromosome of a female is XX while that of a male is XY. When the gamete are formed the mother gamete contain X chromosome gamete while the gametes of father will be of two type, one having X chromosome and another one having Y chromosome.

When X chromosome of female fuses with X chromosome of male a girl child is born while When X chromosome of female fuses with Y chromosome of male a boy child is born.

Adolescence and puberty

When a child takes birth the newborn is called infant till a year, when he starts moving he is called a toddler, then comes the phase of childhood and a fully mature person is called a adult, the time between childhood and adult is adolescence. adolescence is the time when the person is in the process of becoming an adult, who can control their emotions, can act in a society, have intelligence, and is sexually capable.

What is adolescence?

Adolescence is the age in which a person gains social, mental, emotional and sexual maturity. It is the basically the teen age (13 to 19 years). The time when a person faces lots of hormonal changes in his or her body. It is the transition phase from childhood to adulthood.

What is puberty?

Puberty is the time when a person male or female gains sexual maturity. By the end of puberty the person has fully developed reproductive (sex) organs. He/ she has developed all the secondary sex ogans. A boys is biologically ready to become a father and a girl is capable of becoming a mother.

Changes during puberty

Increase in height: during adolescence there is a sudden increase in the height of individual. Generally an individual reaches its maximum height by the end of adolescence.   

Change in physical features: there are many physical changes in an individual during adolescence, although the changes in male and female body are generally different from each other.

     Changes in male:

·         growth of  beard and moustaches

·         chest gets broad

·         development of pubic hair and hair in armpit

·         development in penis

·         enlargement of voice box

·         muscular development of body

    Changes in female:

·         growth of mammary gland and breast

·         pelvic region broadens

·         hips gets broader

·         development of pubic hair and hair in armpit

Change in voice: with the start of adolescence the voice box in case of male gets enlarged and thus the sound coming out of its get hoarse. In certain cases the voice box gets large enough that it can be noticed in the throat.it is also called as adam’s apple. 

Increased activity of sweat and sebaceous gland: the sweat and sebaceous gland gets activated. The sweat gland produces lots of sweat, similarly the sebaceous gland also produce sebum, the oil, leading to skin problems like acne and pimple.

Development of hair: there is development of the pubic hair and the hair in armpit

Mental and emotional maturity: an individual gets mental and emotional maturity at this stage. The brain gets developed at this stage and a person has maximum learning power.

Sexual feeling: during adolescence a liking towards opposite sex  develop

Development of sex organs: the pituitary gland release hormone to activate the sex organs such that they can release the gametes. The ovary release ovum and the testes release sperm it start with the development of sex organs.

Secondary sexual character: sexual character develop in human beings

     Changes in male:

·         growth of  beard and moustaches

·         chest gets broad

·         development of pubic hair and hair in armpit

·         development in penis

·         enlargement of voice box

·         muscular development of body

   Changes in female:

·         growth of mammary gland and breast

·         pelvic region broadens

·         hips gets broader

·         development of pubic hair and hair in armpit

rock and types

What is rock?

Rock is a hard solid substance composed of one or more minerals.

Basically there are three types of rocks

1.Igneous rock

2.Sedimentary rock

3.Metamorphic rock

Igneous rock are the condensed lava that come out of the core of earth and cool down on the surface. When the tectonic plates of earth move causing volcano eruption lava come out from the inner core of earth, this molten lava when settles down on the crust and cools down it solidifies to form hard structure called rock

Igneous rock are of two type: basaltic rock (basalt) and granite

Basalt is formed by cooling of the molten lava on the surface of earth. It is a very fine grained rock

Granite is formed when lava from the core looses its force while come out to earth crust, some lava gets trapped along with the crust i.e , lava gets combined with the coarse soil and after cooling it solidifies in the form of a coarse grained rock

Sedimentary rock, these rocks are formed by the deposition of sediments formed by the weathering of other earthly structures. When the deposits from various sources like wind and water settles down on each other, the continuous pressure exerted by the upper layer hardens the layers beneath forming a hard structure. This hard structure is called sedimentary rock

Metamorphic rock, these rocks are formed when sedimentary rocks present inside the layers of earth undergoes changes in the presence of pressure and heat.