Monday, 26 October 2015

Relevant contributions recently in Science

Bomb-Detecting Plants

   There may come a day when certain plants in your workplace suddenly turn white, at which point everyone will run screaming from the building – those co-workers will have been right to do so, as the white plants indicated that a toxic gas was present. Before that scenario can take place, a little more work still needs to be done, and Colorado State University (CSU) biologist Dr. June Medford is doing it. Using a computer-designed detection trait, she is creating plants that stop producing chlorophyll when they detect pollutants or explosives in the air.
    According to Medford, plants such as tobacco are as good as or better than a dog’s nose for detecting airborne substances. Unlike dogs, however, plants don’t need to be trained, housed or fed. They also don’t need to be powered or protected from the elements, unlike electronics.
    With help from colleagues at Duke University and the University of Washington, Medford redesigned naturally-occurring receptor proteins using a computer program. She then modified the receptors to function in plants, and targeted them to the test plants’ cell walls.
       In the first generation of plants, the receptors were able to detect pollutants and explosives in the air or soil near each plant, and caused chlorophyll suppression within a matter of hours. In future generations of plants, Medford and her CSU team would like to get that reaction time down to a matter of minutes. They are also interested in causing the plants to change color in ways not visible under normal conditions, so that authorities using the right equipment (such as infrared lights) could detect the activity of people such as bomb-makers, before those people knew that they had been detected.
      Once the pollutant or explosive itself has been removed, the plants return to their usual green coloration.
      The sniffer plants could conceivably be “deployed” in high-terrorist-risk locations such as airports, malls or arenas, or around places like schools or people’s homes. If enough of the plants were situated in an outdoor location, satellites would even be able to detect their color changes. Any type of plant could be used, and could be capable of detecting multiple pollutants at once.
       Apparently none of that can happen, however, until many more years of research have been completed. Even then, widely distributing such genetically-modified plants will present legislative and environmental challenges of its own.

THERMAL POLLUTION

THERMAL POLLUTION

Thermal pollution is defined as sudden increase or decrease in temperature of a natural body of water which may be ocean, lake, river or pond by human influence. This normally occurs when a plant or facility takes in water from a natural resource and puts it back with an altered temperature. Usually, these facilities use it as a cooling method for their machinery or to help better produce their products.
Plants that produce different products or waste water facilities are often the culprits of this massive exodus of thermal pollution. In order to properly control and maintain thermal pollution, humans and governments have been taking many steps to effectively manage how plants are able to use the water. However, the effects are still lasting today.

Effects: 

Many organisms are killed instantly by the hot water resulting into a high mor­tality. It may bring other disturbance in the ecosystem. The egg of fish may hatch early or fail to hatch at all. It may change the diurnal and seasonal be­haviour and metabolic responses of organisms. It may lead to unplanned mi­gration of aquatic animals.
Macro-phytic population may also be changed. As temperature is an important limiting factor, serious changes may be brought about even by a slight increase in temperature in a population. For minimising thermal pollution, hot water should be cooled before release from factories and removal of forest canopies and irrigation return flows should be prohibited.

Causes or Sources of Thermal Pollution:

The various causes of thermal pollution are as follows:

(1) Coal-fired Power Plants:

Some thermal power plants use coal as fuel. Coal-fired power plants constitute the major source of the thermal pollution.

(2) Industrial Effluents:

Industries generating electricity require large amount of Cooling water for heat removal. Other industries like textile, paper, and pulp and sugar industry also re­lease heat in water, but to a lesser extent.

(3) Nuclear Power Plants:

Nuclear power plants emit a large amount of unutilized heat and traces of toxic radio nuclear into nearby water streams. Emissions from nuclear reactors and processing installations are also responsible for increasing the temperature of water bodies.

(4) Hydro Electric Power:

Generation of hydro-electric power also results in negative thermal loading of water bodies.

(5) Domestic Sewage:

Domestic sewage is often discharged into rivers, lakes, canals or streams with­out waste treatment. The municipal water sewage normally has a higher tem­perature than receiving water. With the increase in temperature of the receiv­ing water the dissolved oxygen content (DO) decreases and the demand of oxy­gen increases and anaerobic conditions occur.

Control of Thermal Pollution: 

Control of thermal pollution is necessary as its detrimental effects on aquatic ecosystem may be detrimental in the future. Viable solutions to chronic ther­mal discharge into water bodies are as follows:

(1) Cooling Ponds:

Cooling ponds or reservoirs constitute the simplest method of controlling ther­mal discharges. Heated effluents on the surface of water in cooling ponds maximize dissipation of heat to the atmosphere and minimize the water area and volume. This is the simplest and cheapest method which cools the water to a considerable low tem­perature. However, the technique alone is less desirable and inefficient in terms of air-water contact.

(2) Cooling Towers:

Using water from water sources for cooling purposes, with subsequent return to the water body after passing through the condenser is termed as cooling process. In order to make the cooling process more effective, cooling towers are designed to control the temperature of water. In-fact, cooling towers are used to dissipate the recovered waste heat so as to eliminate the problems of thermal pollution.

(3) Artificial Lake:

Artificial lakes are man-made bodies of water which offer possible alternative to once through cooling. The heated effluents may be discharged into the lake at one end and the water for cooling purposes may be withdrawn from the other end. The heat is eventually dissipated through evaporation.
These lakes have to be rejuvenated continuously. A number of methods have been suggested and developed for converting the thermal effluents from power plants into useful heat resources for maximing the benefits.

 

INNOVATIVE LESSON TEMPLATE



INNOVATIVE LESSON TEMPLATE

Name of the teacher  :  Arya S. Raj                                
Date        :  19-08-2015
Name of the School  :  Vimala Hridaya G. H. S. S
Std          :  IX H
Name of the subject  :  Biology                                     
Str           :  63/65
Name of the unit       :  Circulatory path ways               
Period     :  5th
Name of the lesson   :  Structure of heart                                      
Duration :  40 minute


CURRICULAR TREATMENT
        To develop different dimensions of knowledge on the topic “Structure of heart” through group discussion, demonstration, observation and evaluation by questioning, participating in group discussion, reporting and presentation.
CONTENT ANALYSIS:-
Scientific terms:-           
Pericardium, pericardial fluid, auricle, ventricle, arteries, veins.
Facts:

  1. Heart, blood, blood vessels are together consists of circulatory system.
  2. The role of circulatory system is the transport of material throughout the body.
  3. Heart is a muscular organ located behind the sternum within the thoracic cavity.
  4. A persons heart is generally as large as his or her fist.
  5. Heart is protected by double membranous pericardium and the fluid fills the space between the membrane is called pericardial fluid.
  6. The pericardial fluid helps the smoothness of heart.
  7. Human heart has four chambers and upper two chambers are atria and lower two are ventricle.
  8. The atria and ventricle are separated by muscular walls.
  9. Left atrium open to left ventricle and right atrium to the right ventricle.
  10. The valves present between atrium and ventricle to help flow of blood in one direction and it prevent the backward flow of blood.
  11.  Arteries and veins are blood vessels that carry the blood from heart and bring to the heart.
 Concept
Structure of heart
LEARNING OUTCOME
To enable the pupil in

  1. Recognize the structure of heart and recalling the major parts of a heart for developing factual knowledge.
  2. Discussing and identifying the different parts of heart for developing conceptual knowledge.
  3. Generating an idea on the location of heart showing the structure of heart for developing procedural knowledge
  4. Developing scientific process skills like observation, discussion, identification, and classification of different parts of heart
  5. Developing scientific interest about the topic structure of heart
  6. Developing scientific appreciation about heart and its function
PREREQUISITE
The pupil already knows
Heart is the muscular organ which helps in the transport of materials throughout the body
TEACHING LEARNING RESOURCES
A poem showing the concept heart
Class room interaction procedure
Pupil response
Introduction
Teacher ask to the students
Today we are follows a new method of Learning

Presentation
Activity 1
Teacher with the help of a poem that shows the concept as heart and ask the students to discuss about the poem and identify the concept
Poem
Lub dub
Pumping,
Squeeze!
Not 2 arms,
2 eyes,
Nor knees...
Not your legs,
Nor other part,
I never rest,
'Cause I’m your companion
Pumping,
Glop!
No time for sleeping,
I can't stop!
Every second!
Each whole day!
Your whole life!
I work away!
Thumping, thumping
Blood I'm pumping,
Through your veins,
Pump-bump-pump-glumping...
Never stopping,
Not one time.
         
Consolidation
Teacher explains the concept as heart.
Heart is a muscular organ situated behind the sternum in the thoracic cavity between the lungs tighten slightly towards left. A  persons heart is  generally as large as his or her fist



Students listen the poem carefully and identify the concept
































Students listen carefully and understand about structure of heart
ACTIVITY2
Teacher with the help of a power point showing the structure of heart and ask the students to discuss and write the major parts involved in it.
Consolidation
Teacher explains circulatory system consist of heart, blood and blood vessels. Heart is a muscular organ heart is covered by double membranous structure called pericardium and the  fluid that fills the space is called pericardial fluid and it protect the heart and help it to function smoothly. Human heart has four chambers upper two are atria and lower two are ventricle. The atria and ventricle are separated by muscular walls. The valves present between atria and ventricle ensure the flow of blood in one direction.  Arteries and veins are the blood vessels carry blood from heart and bring to the heart.


Students observe the power point presentation carefully and discuss about the structure of heart.





















Students understand the structure of heart and identifies the major parts included

FORMATIVE EVALUATION PROCEDURE

  1. What is the function of circulatory system?
  2. Where the heart was located?
  3. What are the different parts of heart?
  4. What is the function of valves?
  5. How the pericardium helps the heart?
FOLLOW UP ACTIVITY
What are consequences occur in human, when the working of heart stops?
CHALK BOARD SUMMARY

19-08-2015                                       BIOLOGY                               STD: IX H
                                                                                                           STR: 63/65
               Structure of Heart
1       Circulatory system
 Heart, Blood and Blood vessels
2       Pericardium, Pericardial fluid
3       Auricles and ventricles
4       Arteries and Veins