ONLINE ASSIGNMENT

ONLINE ASSIGNMENT

NATIONAL CURRICULUM FRAMEWORK FOR SCIENCE EDUCATION (2005)

             National Curriculum Framework (2005) emphasizes that science curriculum must be used as an instrument of achieving social change in order to reduce the divide based on caste, religion, gender, region, and economic status of the individuals. It identifies three basic issues in the Indian scenario of science education which are as follows:

1. Science education in India is still far from achieving the goal of equity enshrined in the constitution of our country.

2.Science education in Indian develops competence, but does not encourages inventiveness and creativity.

3. It is examination oriented rather than learning oriented.

            These are the challenging issues that require to be changes as soon as possible. NCF 2005 advocates that science is a dynamic, expanding body of knowledge, covering ever new domains of experience. In a progressive, forward looking society, science can play a truly liberating role, helping people escape from he vicious cycle of poverty, ignorance and superstition. In the present fast changing world, the most important skills which an individual needs to develop are flexibility, innovation and creativity. Science education should be true to the child, life and of course, to science itself. For achieving these goals and to make it s strong tool of social change, science curriculum must be valid on the following basic criteria applicable to biology as well:

1. Cognitive validity: If refers to the characteristics of curriculum that make its content, process, language, pedagogical practices and other aspects appropriate to the age and cognitive ability of the children.

2. Content validity : It refers to the characteristics of the curriculum that make its subject matter or syllabus relevant to the child and the society. Content validity means it must be age appropriate, ability appropriate, and level appropriate. It must convey significant and correct scientific information and must be meaningful and simple according to the pupil’ abilities and interest.

3. Process validity: This requires that the curriculum should engage the learner in acquiring the methods and processes of science that lead to generation and validation of scientific knowledge, and nature in him or her natural curiosity and creativity . It is one of the most important creterial as it helped the learners in learning to learn science. Process validity requires constructive approach to teach and learn science, based on student’s own interpretation, reflection on the imparted facts and information and the given situation.

4. Historical validity: It refers to the historical development of science, scientific facts and technology based on them. The curriculum must be prepared with historical perspective in mind 80 that the learners know how science has evolved over the years. Historical validity helps students understand science in social perspective and comprehend how science and society influence each other and how social factors influence the development of science.

5. Environmental validity : If requires that the curriculum should make students understand the complexity of natural environment and how to protect it. Environment validity should enable students appreciate the issues at the interface of science, technology and society. The curriculum should prepare them with the requisite knowledge and skills to enter the professional world.

6. Ethical validity: The curriculum should promote the values enshrined in our constitution, and those in our culture and civilization. It should promote scientific attitude and the values of honesty, objectivity, cooperation, freedom from fear and prejudice and should inculcate in the pupils a concern for life and preservation of the environment.

SCIENCE RELATED TOPIC - 2

SCIENCE RELATED TOPIC - 2

                        OZONE DEPLETION

Introduction: All about Ozone

Like other environmental problems, Ozone Depletion is one that is very troubling, and rightly so, considered as a major environmental issue by all nations on the earth. 
Have you ever felt the sun's intensity ripping through your skin on a hot afternoon? Probably so.
But the sun is no where near the earth. The sun is estimated to be about 150 million kilometers (93 million miles) from our planet earth. Everyday, as the sun rises, we begin to feel the heat. This heat is radiated through millions of space, and yet we still feel it. 
The rays from the sun contain Ultra Violet Rays (UV Rays). UV rays is not all bad, because it helps human with Vitamin D. But too much of it is very dangerous. 
Unfortunately, manufacturing activities since the industrial revolution have caused a disturbance in the atmosphere and opened up for more UV rays to come through to the earth. There have been serious consequences, and potentially it can get worse if we do not act responsibly.
 What is Ozone? 
Ozone is a natural gas composed of three atoms of oxygen. It chemical symbol isO3. It is blue in color and has a strong odor. Normal oxygen (O2), which we breathe, has two oxygen atoms and is colorless and odorless.

scientists have classified O3 into two: Good Ozone and Bad Ozone.

Good Ozone 
Good ozone (also called Stratospheric Ozone) occurs naturally in the upper Stratosphere. The stratosphere is the layer of space 6 to 30 miles above the earth's surface. 
Where does good Ozone come from?
The air is full of gases reacting with each other, even though our eyes do not see. When UV light strikes (Oxygen) O2 molecules, they are split into two individual O atoms — O and O. When one of the O atoms combine with O2 molecule, ozone (O3) is created.
Even though Ozone is only a small part of the gases in this layer, it plays a vital role because it shields us from the sun's harmful UV rays. It is called Good Ozone, for obvious reasons—because it protects humans, life and animals on earth.

Bad Ozone 
Bad Ozone is also known as Tropospheric Ozone, or ground level ozone. This gas is found in the troposphere, the layer that forms the immediate atmosphere. Bad Ozone does not exist naturally. Human actions cause chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOC). 

Where does bad ozone come from?
Each time there is a reaction of chemicals such as those found in cars, power plants and factory emissions, in the presence of sunlight (UV light), Bad Ozone is created.

Bad ozone contaminates (dirties) the air and contributes to what we typically experience as "smog" or haze. 
Note that this kind of smog is different from the deadly London winter type that killed 4000 people. Smog from bad ozone is usually in the summer, caused by the action of sunlight on a mixture of hydrocarbons and oxides of nitrogen. It is known as Photochemical or Summer Smog.


The Ozone Layer

This is simply a layer in the stratosphere containing a relatively high concentration of ozone.

The earth's atmosphere is divided into several layers, and each layer plays an important role. The first region extending about 10km upwards from the earth's surface is called the troposphere. Many human activities like mountain climbing, gas balloons and smaller aircrafts operate within this region.
The next layer, extending about 15-60 km is called the stratosphere. The ozone layer is mainly found in the lower portion of the stratosphere from approximately 20 to 30 kilometres (12 to 19 mi) above earth, though the thickness varies seasonally and geographically. 
The ozone layer protects the earth from the suns UV Rays. If the ozone layer is depleted by human action, the effects on the planet could be catastrophic.
What is Ozone Depletion?
Ozone layer depletion, is simply the wearing out (reduction) of the amount of ozone in the stratosphere. Unlike pollution, which has many types and causes, Ozone depletion has been pinned down to one major human activity.
Industries that manufacture things like insulating foams, solvents, soaps, cooling things like Air Conditioners, Refrigerators and ‘Take-Away’ containers use something called chlorofluorocarbons (CFCs). These substances are heavier than air, but over time, (2-5years) they are carried high into the stratosphere by wind action. 

Depletion begins when CFC’s get into the stratosphere. Ultra violet radiation from the sun breaks up these CFCs. The breaking up action releases Chlorine atoms. Chlorine atoms react with Ozone, starting a chemical cycle that destroys the good ozone in that area. One chlorine atom can break apart more than 100,000 ozone molecules.Ozone layer depletion is best illustrated or explained with the Ozone Bucket Analogy. 
There are other Ozone Depleting Substances (ODS) such as methyl bromide used in pesticides, halons used in fire extinguishers, and methyl chloroform used in making industrial solvents.
Other chemicals that naturally destroy Ozone are Noy, Hox, Clx, which belong to the Nitrogen, Hydrogen and Chlorine families.
Measurements of CFCs in the stratosphere are made from gas balloons, aircraft and satellites.How Ozone Depletion Affects UV Levels?
Depletion of the ozone layer has consequences on humans, animals and plants. This typically results from higher UV levels reaching us on earth. 
 Humans
Research confirms that high levels of UV Rays cause non-melanoma skin cancer. Additionally, it plays a major role in malignant melanoma development. 

This is why it is important to wear UV protection sun-glasses and sun-cream when you stay in the sun to minimise the UV effect on your skin and eyes.
 Plants
The damage that extreme UV levels has on plants is one that our eyes do not see much, but humans can feel the impact. Plant growth, as well as its physiological and developmental processes are all affected negatively. These include the way plants form, timing of development and growth, distribution of plant nutrients and metabolism, etc. These changes can have important implications for plant competitive balance, animals that feed on these plants, plant diseases, and biogeochemical cycles. Marine (or water) Ecosystems
Phytoplankton form the foundation of aquatic food webs. These usually grow closer to the surface of water, where there is enough sunlight. Changes in UV levels is known to affect the development and growth of phytoplankton, and naturally, the fish that feed on them. UV radiation is also know to have affect the development stages of of fish, shrimp, crab, amphibians and other animals. When this happens, animals in the upper food chain that feed on these tiny fishes are all affected. Effects on Biogeochemical Cycles
The power of higher UL levels affect the natural balance of gasses (and greenhouse gases) in the biosphere: e.g., carbon dioxide (CO2), carbon monoxide (CO), carbonyl sulfide (COS) and ozone. Changes in UV levels can cause biosphere-atmosphere feedback resulting from the atmospheric buildup of these gas.
What is Ozone Hole?
Top atmospheric researchers confirm that Ozone levels vary by season and latitude. Sometime in 1979, it was observed the there considerable Ozone depletion in the upper latitudes, Arctic and Antarctic. This massive stretch of ozone depletion (hole) is estimated to be about the size of America. 
Particularly in the antarctic, satellite images were released showing a disturbing thinning of the ozone layer. The phenomenon is what we usually call the Ozone hole, and it was most observed over the Antarctic every year during the spring. 

In the winter, temperatures drop below -78°C (-109°F) in the Poles (Antartic). Thin clouds form of ice, nitric acid, and sulphuric acid mixtures. Chemical reactions on the surfaces of ice crystals in the clouds release active forms of CFCs. This sets the ozone depletion going by spring, a lot of depletion has occurred.
WHAT CAN BE DONE?
Ozone is a natural gas and is naturally replenished over time. This means if we can do something to balance the natural production with its depletion, there should not be a problem. Unfortunately, it does not quiet work like that.
People ask if we cannot produce our own ozone gas to replenish what is lost in the stratosphere. That’s a good question. The sun naturally produces ozone with immense energy and over time. To do the same, we will be looking at using immense energy too, about twice the energy used in the USA. That is just not practical. 
The only way to do that is to remove the excess chlorine and bromine from the stratosphere. And the only way to do that is to stop making CFCs and several other chemicals. This is why in the 1990s a meeting of the worlds big nations met and agreed to reduce the usage of CFCs and also encouraged other nations to do the same. That was decided in the Montreal Protocol.

SCIENCE RELATED TOPIC - 1

SCIENCE RELATED TOPIC - 1

 RADIOACTIVE POLLUTION

 The radioactive pollution is defined as the physical pollution of air, water and the other radioactive materials. The ability of certain materials to emit the proton, gamma rays and electrons by their nuclei is known as the radioactivity. The protons are known as the alpha particle and the electrons are also known as the beta particle. Those materials are known as the radioactive elements. The environmental radiations can be from different sources and can be natural or man made.

The natural radiations are also known as the background radiations. In this the cosmic rays are involved and reach the surface of earth from space. It includes the radioactive elements like radium, uranium, thorium, radon, potassium and carbon. These occur in the rock, soil and water. The man made radiations include the mining and refining of plutonium and thorium. This production and explosion of nuclear weapons include the nuclear fuels, power plants and radioactive isotopes.

 The first atom bomb was exploded in the Japan in the year 1945. It affected the Hiroshima and Nagasaki cities. It adversely affected the flora, fauna and humans of that area. In spite of these destructions the nuclear race is still going on between different nations. The nuclear arms are tested with the production of nuclear weapons.

 The radioactive elements are produced in the environment and affect other materials also. It includes the strontium, radium and iodine. The gases and particles are produced by the radioactive materials. They are carried by the wind and the rain brings down the radioactive particles to the ground which is referred as nuclear fallout. The soil transfers these radioactive substances to the plants and ultimately they reach the human body and cause many side effects. The iodine may affect the white blood cells, bone marrow, spleen, lymph, skin cancer, sterility, eye and damage to the lung. The strontium has the ability to aggregate in the bones and form a bone cancer and leads to tissue degeneration.

 The radioactive materials are passed through the land to water and cause an adverse effect on the aquatic animals. They reach to human through the food chain. The nuclear power generates a lot of energy which is used to run turbines and produces electricity. The fuel and the coolant produce a large amount of pollution in the environment. The atomic reactors are also rich in the radioactive materials. There biggest problem is in their disposal and if they are not properly disposed they can harm the living organisms. If they escape they can cause a hell lot of destruction. The gases escape as a vapor and cause pollution on the land and water. The use of radioactive isotopes is multipurpose. They are of a great scientific value and they may be present in the waste water. From these water resources they reach to the human body via food chain. The people who work in power plants have more chances of the exposure to harmful radiations. The human beings also receive the radiation and radiotherapy from the x rays.

 

 

 

 

 

 

 

 

LESSON TRANSCRIPT, INDUCTIVE THINKING MODEL

Name of the teacher : Asha M.S                                               Standard:10 Subject                    : Physics                                                     Date     :8-9-14 Unit                        : Energy Management Topic                     : Renewable and non renewable                                 resources

Name of the concept : Renewable and non renewable resources

OBJECTIVES

• Pupil develop observation skills
• Identification of different types of renewable resources
• Generalisation about property of renewable resources
• Pupil develops hypothesis predicting results.

PHASE 1 : Date Categorisation

T:What is the common property of petrol, Kerosine and wood?

S:They are all fuels

T:Can you name some other fuels that we use in our delay life?

S:Disel, CNG, Biogas, LPG, Gober gas, cowding cake.

T:Can you group them based on their similarities

Group A	Group B
Biogas	Diesal
Wood	Petrol
Cowding cake	CNG
Gobergas	LPG

PHASE 2 : Interpretation of data

T : Now let us analyse the above mentioned examples. How did you classify them?

S: Items in group A can be produced at home. But in B cann’t

T: Very good, anything else?

S: Items in group a are easy to handly

T: Yeas, are there any more difference?

S: Group A items are easily available in nature and can be replaced once they are used.

T: Absolutely right. Can you name them ?

S: No teacher

T :They are renewable and non renewable resources. Non renewable resources are those resources that can’t be replaced by once they are used up.

Renewable resources are those resources that can be replaced as they are used.

PHASE 3 : Application of Generalisation

T: Now I will give you some examples. Identify them?

Sunlight

S: Renewable

T: Yes. Why it is renewable?

S: Because it can be replaced once they are used up

T: Yes, then coal?

S: Non renewable

T: Very good, Air?

S: Renewable

T: So renewable resources are those resources that can be replaced as they are used non renewable resources are those resources that cann’t be replaced as they are used up.

 

Colours of light from Fareeda Beegum R S