Friday, 19 September 2014

science facts 1 ( Lekshmi Mohan.N )

10 Surprising secrets from Apollo 11's Historical moon landing

This year is the 45th anniversary of the Apollo 11 moon landing, the first time humans walked on the moon. The iconic imagery and audio from the mission is certainly seared into humankind’s collective consciousness, but there are a handful of side stories from the mission that are often overlooked. Here are some of the historical anecdotes that will change the way you remember man’s first foray on the moon. 




10. “In the Event of Moon Disaster” 
Had the Apollo 11 moon landing gone horribly wrong, the world may have immortalized the words of William Safire, Richard Nixon’s speechwriter. You see, Safire had written a statement for Nixon to deliver in the wake of a hypothetical moon disaster. Rather than Neil Armstrong’s famous words, we may have committed an equally poetic phrase to memory: “Fate has ordained that men who went to the moon to explore in peace will stay on the moon to rest in peace.”
9. A Famous Misquote? 
When Neil Armstrong took his first step on the moon, he actually meant to say “That’s one small step for man.” People have argued whether a shoddy radio connection caused the misquote, or if Armstrong had a case of global stage fright and skipped over the tiny, but important, word.





8. Speaking of Those ‘First’ Words…
Armstrong gets all the credit for uttering the first words on the moon, but “That’s one small step…” wasn’t the first lunar sentence spoken — technically. Bob Berman, Slooh astronomer and author of Zoom, tells a different story that came out of an interview with Aldrin years ago. Berman says Aldrin was actually the first man to speak on the moon, but his quote wasn’t nearly as sexy. When the lander touched down, Aldrin simply said, “OK, engines stop.”

7. Armstrong Was Too Good a Pilot
Although it seems counter-intuitive, Armstrong landed the Eagle too softly on the surface of the moon. Berman says Armstrong was supposed to cut the engines when the lander was a few feet from the surface. NASA scientists built the lander with legs that would crumple upon impact to absorb the shock. Since Armstrong was such an ace pilot, the lander’s legs never crumpled. As a result, the astronauts had to exit the lander several feet higher than intended, which means that first small step was more of a leap.
6. That’s One Soggy Step 
Armstrong was the first human to step foot on the moon, but Aldrin holds the title as the first man to urinate on it. Upon stepping foot on the moon, Aldrin promptly emptied his bladder into his space suit’s internal urine collector. Unfortunately, Armstrong’s piloting skills came back to haunt Aldrin: when he made his higher-than-expected leap from the Eagle, his urine collector broke upon sticking the landing. As a result, one of Aldrin’s boots filled with pee when he relieved himself, Berman says. Fully aware that he was on a live radio feed, Aldrin kept that bit of information to himself.



5. The Moon’s Aroma
Have you ever wondered what the moon smells like? When Aldrin and Armstrong, caked with moon dust, returned to the Eagle lander, they reported that the moon smelled a bit like wet ashes and gunpowder. Pressurizing the cabin upon their return was in itself a worrisome operation: some folks believed lunar dust was flammable, and would ignite as soon as it came in contact with oxygen. Luckily, that wasn’t the case.
4. Broadcasting in HD
We all remember that iconic video feed beamed to hundreds of millions of earthlings in 1969, but the video was actually captured in higher quality than we ever saw. That’s because the camera captured video in a format that commercial television stations couldn’t broadcast. NASA used a scan converter to adapt the video for U.S. broadcast signals, but by the time the images appeared on home television sets, the feed was substantially degraded.


3. A Mother’s Concern
There are myriad things a moonwalker’s mother could worry about, but Neil Armstrong’s mom had just one real concern: that the lunar crust was too delicate and wouldn’t support her son’s weight when he walked on it.
2. What We Left Behind
Although every man on the Apollo 11 mission returned to Earth safely, they left plenty of artifacts back on the moon. Some items, such as a golden olive branch, American flag, Apollo 1 patch and a moon memorial disk, served a symbolic function.
But there was also plenty of junk left behind, including television cables, a camera, urine and defecation collection devices, tongs and a hammer to name a few. NASA has compiled a list of every single item the Apollo missions left behind on the moon.
1. A Second Chance
Aldrin may have never had the chance to walk on the moon because NASA turned down his initial application to become an astronaut. He tried again, and was accepted in the third group of astronauts in 1963; he became known as “Dr. Rendezvous.”

E-waste (Lekshmi Mohan.N)

E-waste  constituents and it's effect on health

"E-waste" is a popular, informal name for electronic products nearing the end of their "useful life. "E-wastes are considered dangerous, as certain components of some electronic products contain materials that are hazardous, depending on their condition and density. The hazardous content of these materials pose a threat to human health and environment. Discarded computers, televisions, VCRs, stereos, copiers, fax machines, electric lamps, cell phones, audio equipment and batteries if improperly disposed can leach lead and other substances into soil and groundwater. Many of these products can be reused, refurbished, or recycled in an environmentally sound manner so that they are less harmful to the ecosystem.
                                     

  1. The nation now dumps between 300 million and 400 million electronic items per year, and less than 20% of that e-waste is recycled.
  2. E-waste represents 2% of America's trash in landfills, but it equals 70% of overall toxic waste. The extreme amount of lead in electronics alone causes damage in the central and peripheral nervous systems, the blood and the kidneys.
  3. Because computer processing power doubles roughly every two years, many old computers are being abandoned. Only 15% recycle their computers, which means the other 85% end up in landfills.
  4. It’s energy efficient to rebuild old computers, but only about 2% of PCs ever find their way to a second user.
  5. About 50 millions cell phones are replaced worldwide a month, and only 10% are recycled. If we recycled just a million cell phones, it would reduce greenhouse gas emissions equal to taking 1,368 cars off the road for a year.
  6. Flat panel computer monitors and notebooks often contain small amounts of mercury in the bulbs used to light them.
  7. Cathode ray tubes in older TVs and computers typically contain about 4 lbs of lead and sometimes as much as 7 lbs.
  8. The European Union banned e-waste from landfills in the 1990s, and current laws hold manufacturers responsible for e-waste disposal.
  9. Large amounts of e-waste have been sent to countries such as China, India and Kenya, where lower environmental standards and working conditions make processing e-waste more profitable. Around 80 % of the e-waste in the U.S. is exported to Asia.
  10. E-waste legislation in the United States is currently stalled at the state level. Just 24 states have passed or proposed take-back laws. However, as of January 1, 2011, covered electronics are completely banned in West Virginia.
  11. Electronic items that are considered to be hazardous include, but are not limited to:
    • Televisions and computer monitors that contain cathode ray tubes
    • LCD desktop monitors
    • Laptop computers with LCD displays
    • LCD televisions
    • Plasma televisions
    • portable DVD players with LCD screens                           









 Effects of E-Waste constituent on health

Source of e-wastes
Constituent
Health effects
Solder in printed circuit boards, glass panels and gaskets in computer monitors
Lead (PB)
  • Damage to central and peripheral nervous systems, blood systems and kidney damage.
  • Affects brain development of children.
Chip resistors and semiconductors
Cadmium (CD)
  • Toxic irreversible effects on human health.
  • Accumulates in kidney and liver.
  • Causes neural damage.
  • Teratogenic.
Relays and switches, printed circuit boards
Mercury (Hg)
  • Chronic damage to the brain.
  • Respiratory and skin disorders due to bioaccumulation in fishes.
Corrosion protection of untreated and galvanized steel plates, decorator or hardner for steel housings
Hexavalent chromium (Cr) VI
  • Asthmatic bronchitis.
  • DNA damage.
Cabling and computer housing
Plastics including PVC
Burning produces dioxin. It causes
  • Reproductive and developmental problems;
  • Immune system damage;
  • Interfere with regulatory hormones
Plastic housing of electronic equipments and circuit boards.
Brominated flame retardants (BFR)
  • Disrupts endocrine system functions
Front panel of CRTs
Barium (Ba)
Short term exposure causes:
  • Muscle weakness;
  • Damage to heart, liver and spleen.
Motherboard
Beryllium (Be)
  • Carcinogenic (lung cancer)
  • Inhalation of fumes and dust. Causes chronic beryllium disease or beryllicosis.
  • Skin diseases such as warts.

lesson plan (lekshmim Mohan.N)

CONCEPT ATTAINMENT MODEL
LESSON TRANSCRIPT


Name of Teacher  :   Lekshmi Mohan.N                                                        standard: IX
Name of school     :   C.M.G.H.S Poojappura                                                 Date:4/7/2014
Subject                  :   Physics
Unit                      :   oscillations
Sub-unit                :   periodic motion

I.    Name of the concept : Periodic Motion
II.  Definition of the concept: any motion that repeats itself at regular intervals of time is                                                                       known  as  periodic motion
III. Essential Attributes
1.      Time interval
2.      Repeated motion
IV. Non-Essential Attributes
            Duration,Shape and size of the object
V. Preparing exemplars

Positive exemplars

Negative exemplars

Motion of hour hand of a clock
Motion of second hand of a clock
Heart beat of a healthy person
Motion of pendulum
Rotation of earth
Revolution of earth

Launching of rocket
Boy running along a straight path
Motion of bullet
Falling of Mango
Falling of Raindrops
Crawling of snake

VI . Instructional Effects
1.      Competency for close , meaningful observation of examples non-examples leading to attribute analysis
2.      Ability to identify the essential attributes of the members of the category
3.      Competency to generating meaningful hypothesis regarding the new category
4.      Practice of testing hypothesis formed in the light of new examples
5.      Skill for categorising items observed on the basis of essential attributes and to justify
6.      Skill to define the category formed, in terms of essential attributes.
7.      Ability to generate new examples independently and to test the acceptability of them.
VII . Nurtural effects
1.      Acquires sensitivity to logical reasoning
2.      Becoming tolerant to ambiguities
3.      Developing positive attitude towards alternate perspectives.



PHASE 1
   
Presentation of data and concept identification
   
T :  Dear students , here we are going to play a game. I have a concept in my mind. I’ll provide you some positive exemplars ( YES example) for the concept in my mind and some negative exemplars ( NO example) which do not bear the characteristics of the concept. All  the YES exemplar have some attribute in common. By comparing the exemplars , you have to identify the concept in my mind , it's characteristics and suggest some more examples.Moreover based on the attributes , you have to define the concept. Here is a pair of +ve and –ve examples.
     Motion of hour hand of clock ( +ve )
     Launching of a rocket ( -ve )
Can you identify the motion?
   S : Slow motion
   S : Circular motion

T : Now listen here is your second set of examples
      Motion of second hand of a clock ( +ve )
      Boy running along a straight path ( -ve )
    S : It is surely circular motion 
 T : If so , check the next set of examples
      Heart beat of a healthy person ( +ve )
      Motion of a bullet ( -ve )
    S : something that is not related to straight line motion ( translator motion )
   S : Can you give some more examples?
   T : Let us see the next set
       Motion of pendulum ( +ve )
       Falling of Mango ( -ve )
    S : In all the positive examples the motion of the object repeats itself


    T : You are absolutely right.Can you name the motion?
    S : No teacher
    T : All right, I’ll tell you. This is known as periodic motion



Any motion that repeats itself at regular intervals of time is known as periodic motion


PHASE 2
Testing attainment of the concept
T : Now I am going to check your knowledge about periodic motion. I will give you a set of examples from which you should identify the 'YES' example and 'NO' example.
     Revolution of earth and
     Crawling of snake.
S : Revolution of earth – YES
     Crawling of snake – NO
PHASE 3
Analysis of thinking stratergy
T : Can you explain how did you reach your conclusion ?
S : Teacher , your first +ve examples of motion of hour hand of a clock made us think that the concept might be something related to circular motion. The second example also confirms our hypothesis but then you provided the next +ve example of motion of a pendulum. Thus that hypothesis was rejected .
T : Then how did you reach the correct conclusion  ?
S : We analysed the +ve and –ve examples again and again. On comparing we came to identify that in all the +ve examples , the motion of the object repeat itself. Thus we arrived at the concept of periodic motion.
    










Orientation to the process













Teacher presents the first pair of labeled examples.


Hypothesis 1
Hypothesis 2


Teacher presents the second pair of labeled examples.


Teacher presents the third set of labeled examples.

Hypothesis 3.



Teacher presents the fourth pair of labeled examples.

Hypothesis 3 is rejected.
Hypothesis 4 formed.



Teacher name the concept.













Student label the unlabelled examples.










LESSON PLAN (LEKSHMI A S)

CONCEPT ATTANINMENT MODEL
LESSSON TRANSCRIPT


Name of shcool:                                                                                        Standard : IX.C
Name of teacher: Lekshmi. A.S                                                                Strength:
Subject                : Chemistry                                                                    Date:
Unit                     : Separation of Mixtures                                                Duration:45min
Topic                   : Adsorption



I. Name of the concept              : Adsorption
II.Definition of the Concept  :                                                                                                          
A process of retaining the molecules of a substance on the surface of another substance [liquid / solid] resulting into a higher concentration of molecules on the surface.
III. Essential attributes           :                                                                                                          
           I.Adsorbate
           II.Adsorbant
           III.Increase in concentration of adsorbate molecules on the surface of adsorbent.  
                       
                                                                                                 
IV.Non essential attributes :                                                                                                                      
Colour, amount, shape, climate
V. Preparing Exemplars           
                                                                                                                                  
Positive Exemplars
Negative Exemplars
Ink spreading on chalk
Wetting of sponge
Dust particle sticking on the surface of wall
Tissue paper get wetting
Spreading of ink on the surface of the thermocole
Cotton gets wetting
Dust particles on the mats
Soil absorbing water
Coal adsorbing harmful gases
Roots absorbing water from soil
Charcoal used for adsorbing colored and harmful substance for purification of water
Rasagula
Chalk dust on black board
Water adsorbed by bricks
Oil on steel plate
Biscuit dipped in tea
Paint on wall
Clothes put in bucket of water
Spreading of ink on glass paper
Wetting of paper
Charcoal in water purification
Clay absorbing water
Water on lotus leaf
Plants absorbing minerals from soil

VI. Instructional Effects:                                                                                                                                           
1.      Competency for close, meaningful observation of examples and no examples leading to attributes analysis.
2.      Ability to identify the essential attributes of the members of the category.
3.      Competency to generating attributes meaningful hypothesis regarding the new category.
4.      Practice of testing hypothesis formed on the light of new examples.
5.      Skill for categorizing the items observed on the basis of essential attributes and to justify.
6.      Skill to define the category formed, in terms of essential attributes.
7.      Ability to generate new examples, independently and to test the acceptability of them.
VIII. Nurturant Effect.
1.      Acquires sensitivity to logical reasoning.
2.      Becoming tolerant to ambiguities.
3.      Developing positive attitude towards alternate perspectives.

SYNTAX
PHASE 1
Presentation of data and concept identification

T: Dear students, here we are going to play a game. I have a concept in my mind. I’ll provide you some positive exemplars (YES example) for the concept in my mind and some negative exemplars (NO examples) which do not bear the characteristics of the concept. All the Yes examples have some attributes in common. By comparing the examples you have to identify the concept in my mind its characteristics and suggest some more examples. Moreover based on the attributes you have to define the concept.

Here is a pair of positive and negative examples.
Dust particles sticking on wall (+ve)
Wetting of sponge (-ve).

S: Mixing of molecules of different substance.

S: Adhesive force between different molecules.

T: Now, listen here is your second set of examples spreading if ink on chalk piece (+ve)
wetting  of bricks (-ve)

S: Attraction between two different molecules.

T: If so check the next set of examples.
Dust particles stick on wall (+ve)
Wetting of cotton (-ve).

S: in one case one type of molecule is present on second and in other case the second type of molecule spread over the first fully.

S: can you give more examples.

T: Yes sure, see the next set
Charcoal used in water purification (+ve)
Intake of water by plants (-ve)

S: In all positive examples II type molecule is trapped on the surface only and the negative examples are bulk process.

T:That’s right anything more?

S: One type of molecule is present on the surface of other molecule only.

T: Yes, you are absolutely correct can you name concept?

S: No, teacher.

T: All right, I will tell you. This process is known as adsorption, Can you list the attributes of adsorption and also perspective of adsorption and also perspective of adsorption one more.

S: In adsorption there are two substance adsorbent and adsorbate are required.

S: It is a surface process.

T: Very good.
Adsorption Is the process of retaining the molecules of a substance on the surface of another substance resulting, into a higher concentration of molecule on the surface of the substance.
 
In the above mentioned +ve examples shape of the substance is a non-essential attributes of adsorption. Can you suggest some other non essential attributes?

S: Ok, Colour of the substance.

T: anything more?

S: amount of the substance.

T: very good.

S: Climate.

T: Absolutely right.

PHASE 2
Testing the attainment of the concepts

T: Now I am going to check your knowledge about adsorption. I will give you a set of examples from which you should identify the YES examples and the NO examples
Spreading of ink on glass plate.
Wetting of clay.

S: Spreading of ink on glass plate: YES.
    Wetting of clay: NO.

T: Now listen the next set
Chalk dust on board.
Rasagula.

S: Chalk dust on board: YES.
    Rasagula: NO.

T: Now listen the next set of example.
Painting the wall.
Wetting of clothes.

S: Painting the wall: YES.
    Wetting of clothes: NO.

T: Very good. Can you define adsorption?

S: The process of retaining the molecule of a substance on the surface of another substance is adsorption.

T: Can you suggest some more examples.

S:  Oil on glass plate.

S: Water on leaf surface.

S: Dust on floor.

T: Very good.

PHASE 3
Analysis of the Thinking Strategy.

T: Can you explain how you reached your conclusion.

S: Teacher, your first +ve example, dust particles sticking on wall and –ve example wetting of Sponge made use of think the concept might be something related to mixing of two different types of molecules. But then you provided the next +ve example of spreading of ink on chalk piece leads to the rejection of Hypothesis 1 and Hypothesis of adhesive force remains.

T: What about the next example?

S: When you told about dust particles sticking on wall and wetting of cotton, we thought that the concept was related to amount of one type of molecule on another molecule leading to Hypothesis 3.

T: Then how did you reach the correct conclusion?

S: We analyzed all the +ve and –ve examples again and again on comparing, we came to identify that in all the +ve examples there is an increase in concentration of substance on the surface of another substance. Thus we arrived at the concept of adsorption.

T: Very good.










Orientation to the process.








Teacher present the first pair of labeled examples

Hypothesis 1

Hypothesis 2

Teacher presents the second set of labeled examples.

Hypothesis 2 persists
Hypothesis 1 rejected
Teacher present the third set of labeled examples.

Hypothesis 3





Teacher presents the fourth pair of examples.


Hypothesis 4
Hypothesis 3 persists




Hypothesis 5






Teacher name the concept



Students list the essential attributes





Teacher states the concept rule





Students list the non essential attributes.















Teacher presents first set of unlabeled examples.


Students label unlabeled examples.





Students label unlabeled examples.





Students label unlabeled examples.



Students states concept rule.



Students generate additional examples.












Student describes thought.








Discuss the role of Hypothesis.