Science and everything The importance of practical work and science as a context. [email_address] [email_address] Resources available online on the science connected wiki: http://scienceconnected.wetpaint.com/
I want to track down the book that has a reference to a pub I visited a week ago
………… .travel back in time and space one week and 12,000 miles.
Leave the train….back into the station….back in time five minutes .
Back into the pub… back in time another two minutes
Good ale……but travel back in time another five minutes
Perfect but travel back in time 2.2 billion years……I think. The reference is in the Bill Bryson book whose title I have forgotten
The bar top is made from ancient orbicular granite
Granite is an igneous rock
It cooled slowly deep inside the earth’s crust.
It is light coloured and has large crystals
At 2.2 billion years there was no oxygen or life as we know it on the planet.
Science is the ultimate context
Science has been remarkably successful at describing everything that has happened in the universe since it exploded into life with the sort of energy that scientists are trying to recreate deep inside the Large Hadron Collider in CERN.
Give us your learning contexts and allow us to tease out the science.
A short history of everything
In the beginning there was the laws of physics 13.6 billion years ago
Then 12 basic particles appeared as a plasma because it was very hot
And four different forces
… and now the present: It is a lot colder and there are fewer particles. luckily we are close enough to the sun to feed off its energy
Can we rely on the sun?
The sun is losing mass at an alarming rate, 4 million tons every second
The temperature at the core is important, it has to be high enough to allow the nuclear fusion of hydrogen into helium
The neutrino problem
When the sun is healthy it produces lots of particles called neutrinos (small neutral particles with hardly any mass)
In the sixties there was evidence that neutrino production was only a third of that expected
Oh no we were doomed!... something was wrong with the sun
Scientific experiments and the sun
Experiments need to be carefully designed
Data has to be collected accurately.
Experimental results must be reproducible
Only one variable at a time is changed during a scientific investigation
All other variables are controlled
Scientists needed to go to extraordinary lengths to investigate the sun and control variables
The search for missing neutrinos
Neutrinos are tiny sub atomic particles with hardly any mass and no charge
Because they can’t be easily stopped by matter they are almost impossible to detect.
They are produced in unimaginable numbers every second as hydrogen gas is turned into helium in the sun.
They mostly pass straight through the earth
The odds against detecting a neutrino are much greater than buying an intergalactic lotto ticket……..but
Every now and again a neutrino can bump into a chlorine atom, give of a flash of light and turn into a radioactive Argon atom
This can be detected…..but it isn’t easy
Catching neutrinos: Homestake gold mine South Dakota1966
At 4900 feet the only radiation that would penetrate this far are neutrinos.
The detector a tank, 20 feet in diameter and 48 feet long, held 100,000 gallons of perchloroethylene. (dry cleaning fluid)
How effective was this neutrino catcher
On a good day 10 neutrinos flying out from the sun at the speed of light should be trapped as radioactive argon
On average they detected 3
Was the experiment flawed
Was the model that predicted neutrino numbers flawed
Sunny end to the story
Both the theory and experiment have since been validated….but it took 40 years
Raymond Davis the designer of the experiment finally received a Nobel prize in 2002
The sun is good for another 4.5 billion years
Student worksheet: vinegar analysis
How do you ensure a fair test.
What will you measure?
What needs to stay the same?
Can you repeat and get similar results?
How could you improve the experiment?
What happens next?
Other scenarios for the same experiment
Student worksheet: Shoes
What other investigations could follow from this?
Can we help you?.
Its only a theory
Evolution is only a theory
Scotland will probably never win a rugby world cup
Gravity is only a theory.
Oxford dictionary theory definition 1
A scheme or system of ideas or statements held as an explanation or account of a group of facts or phenomena. A hypothesis that has been confirmed or established by observation or experiment, and is propounded or accepted as accounting for the known facts. A statement of what are to be the general laws, principles or causes of something known or observed.
Oxford dictionary theory definition 2
A hypothesis proposed as an explanation; hence, a mere hypothesis, speculation conjecture; an idea or set of ideas about something, conjecture; an idea or set of ideas about something; an individual view of a notion.
Raymond Davis: Solar neutrino experiments
Brookhaven National Laboratory press release 1967
Brookhaven National Laboratory Bulletin Board.
For further assistance [email_address] [email_address] Resources available online on the science connected wiki: http:// scienceconnected.wetpaint.com /