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Science communication is important in today's technologically advanced society. A good part of the adult community is not science saavy and lacks the background to make sense of rapidly changing technology. My blog attempts to help by publishing articles of general interest in an easy to read and understand format without using mathematics. I also give free lectures in community events - you can arrange these by writing to me.

Saturday, 8 November 2008

Web Links to CT Scan Videos and Pictures

There are some interesting videos on the Web that demonstrate the capabilities of CT Scans - in particular the 3D nature of the information and the ability to extract views of the internal organs from any angle. Some of the links are:

BBC: This describes the perfomance of Philips Brilliance CT256

< http://news.bbc.co.uk/go/em/fr/-/1/hi/health/7112688.stm >

TOSHIBA: There are many 3D video clips on the site - any many more pictures from their AquilionOne 320 Slice Scanner.


I am sure there are many more sites to search for interesting video clips.

A Good source of information about the detector system used in multi slice scanners is


Enjoy !!

Saturday, 25 October 2008

Different Imaging methods....Compare resolution

Most techniques provide resolution of the order of 1 mm

Resolution - Smallest feature that may be seen clearly

X-Ray Films 0.1 mm X-ray radiation

Mammography 0.03 X-ray radiation

CT Scan 0.4 X-ray radiation

PET Scan 5-7 Nuclear radiation

MRI 1.0 Radio-frequency

Ultrasound 0.3 Sound waves

Science for All talks start on 1st November 2008...

A new series of five talks starts on Saturday 1st November 2008. The programme is as follows:

Talk 1 (01/11/2008): X-ray Imaging
Talk 2 (08/11/2008): Computer Assisted Tomography (CT Scans)
Talk 3 (15/11/2008): Ultrasound Scans
Talk 4 (22/11/2008): Positron Emission Tomography (PET Scans)
Talk 5 (29/11/2008): Magnetic Resonance Imaging (MRI Scans)

Free Science Talks for Secondary Pupils & Adults
No Science Background Needed
11 am – 12 noon on Saturdays
1, 8, 15, 22 & 29 November 2008
James Watt Auditorium, E.K. Technology Park, G75 0QD
(Ample free parking on site)
In Partnership with: Glasgow University
Scottish Enterprise, Lanarkshire
Further Information: ekTalks@yahoo.co.uk
Since the discovery of X-rays over 100 years ago with their potential for medical imaging, developments in physics have been vital to the advancement of medicine. MRI, CT, PET and ultrasound scans, and various types of radiotherapy are some of the physics-based devices that help diagnose and treat ailments ranging from broken bones to cancer.

Dr Singhal will explain the science behind medical imaging. The talks are aimed at the general audience and no prior background in physics or biology is assumed. The talks are particularly suitable for secondary school pupils who are encouraged to attend. The presentation is visually attractive and highly informative. Talks are free to attend.

The talks are part of the community education initiative under the Science for All programme

Friday, 8 February 2008

Prefixes to Units...

We normally write:

Average weight of a newborn baby is W = 3.5 kg
Planes fly at an altitude H = 8,000 m
An hour has 3600 s

Value of a physical quantity is expressed as a comparison to a unit of that quantity. For example, the value of a physical quantity Z is written as the product of a unit [Z] and a numerical factor n: Z = n[Z]

SI syatem is the metric system used internationally in science and engineering

In the SI system, kilogram (kg), metre (m) and second (s) are the base units of mass, length and time respectively.

Other commonly used base units in the SI system are

Energy - Joule (J)
Power - Watt (W)
Electric potential - Volt (V)

Units may be combined to express complex quantities

Speed is distance travelled in unit time - so its base unit will be
metre per second or m/s or ms-1

Frequently one needs to deal with very large or very small values and it is common to use a prefix with the base unit to obtain a derived unit. For example

Radius of the Earth is 6,450,000 m or 6,450 km {1 km = 1000 m}

Size of a virus is 0.0000001 m or or 0.1 microm or 100 nm
{1 micrometre = 0.000001 m; 1 nm = 0.000000001 m or 10-9m}

Standard Prefixes are in steps of 1000 - they are listed in the following for distance measurements. Others are similar.

Large numbers:

1,000 m = 103m or 1 km
1,000,000 m = 106m or 1 Mm
1,000,000,000 m = 109m or 1 Gm
1,000,000,000,000 m = 1012m or 1 Tm
1,000,000,000,000,000 m = 1015m or 1 Pm petametre
1,000,000,000,000,000,000 m = 1018m or 1 Em
1,000,000,000,000,000,000,000 m = 1021m or 1 Zm zettametre

Small Numbers:

0.001 m = 10-3m or 1 mm millimetre
0.000,001 m = 10-6m or 1 microm micrometre
0.000,000,001 m = 10-9m or 1 nm nanometre
0.000,000,000,001 m = 10-12m or 1 pm picometre
0.000,000,000,000,001 m = 10-15m or 1 fm femtometre
0.000,000,000,000,000,001 m = 10-18m or 1 am attometre
0.000,000,000,000,000,000,001 m = 10-21m or 1 zm zeptometre

Friday, 1 February 2008

Writing numbers that are very big or very small ...

In science, you will encounter numbers that are very big or extremely small. These can be rather inconvenient to write out in the normal notation. Powers of ten is a useful shorthand method of writing very large or very small numbers. For example,

One thousand (1000) is 103 ; reads 'ten to the power 3' and is 1 followed by 3 zeros
One divided by 1000 is 0.001 or 10-3 ; reads 'ten to the power minus 3'

And that is it - the positive power on ten tells us how many zeros are after 1.
negative powers of ten tell us the position of the 1 after the decimal point.

Distance of the Sun from the Earth is 150 million km or 150,000,000 km or 15 x 107 km.
Diameter of an atom is 0.0000000002 m or 2 x 10-10 m.

Multiplication and division of powers of ten numbers is very easy...

When you multiply two numbers powers add

When you divide two numebrs powers substract.

Example: Multiply 2 million by 4 million

Longhand: 2,000,000 x 4,000,000 = 8,000,000,000,000

Powers of ten: 2 x 106 x 4 x 106 = 8 x 1012

Nuclear Talks...

The following programme is tentative. The talks will be suitable for practically everybody to attend (particularly for those who have felt that science is not for them/ I have never read science/ it is too difficult...). The talks will be presented in a visually attractive manner with no mathematics. The atmosphere is very friendly and relaxed (it is not like school!)

Please encourage your friends and neighbours to come too. The talks are free to attend.

Talk 1: Introduction to the nucleus; we shall address questions about the size, shape, what is the nucleus made of, what holds the nucleus together etc. Rutherford's discovery of the nucleus revolutionised our understanding of the structure of matter.
Talk 2: Radioactivity and its many applications like radio-isotope dating for finding ages of fossils and other objects of historic interest, nuclear medicine etc. will be discussed. Radioactivity is due to the decay of a nucleus into another by emission of energy in the form of alpha, beta and gamma radiation. We shall look at the fascinating history of the discovery of radioactive elements, the reasons why nuclei decay and the nature of the radiation that is emitted.
Talk 3: Nuclear binding energies, Nuclear fission and fusion; explain how energy is released in the fission of uranium and in fusion of hydrogen. We shall look at the particularly interesting history of the discovery of nuclear fission and the development of atomic bomb.
Talks 4 and 5: We look at global energy scene - present and future consumption trends and their impact on our climate. UK energy supply and consumption has special challenges and possibilities. We analyse aspects of nuclear power production in detail with a critical look at those of serious public concerns. Future nuclear reactor designs.

Sunday, 20 January 2008

Science for All Talks in East Kilbride....

Fourth in the series of talks aimed to increase public awareness of science will discuss the atomic nucleus and the controversial issue of nuclear power. Study of the nucleus is driven by the desire to learn about the fundamental constituents of matter – essentially, what we are made of? Our understanding of laws that govern the behaviour of matter has benefited enormously from such studies. Paradoxically, the understanding of the nucleus has been responsible for our current view of the origin of the Universe.

On a more practical level, medical advances like MRI, PET scanners, radiotherapy have come about from the study of nuclei. The world-wide-web was invented to facilitate communications between nuclear physics laboratories. Radio-isotope dating techniques have allowed us to establish the way the Earth’s climate has changed in the past.

Nuclear fission has been harnessed to generate environmentally clean power, although it has its associated concerns regarding radioactive waste disposal. The Sun maintains its prodigious energy flow through nuclear fusion of hydrogen. The development of nuclear fusion has the possibilities of supplying limitless energy in the future.

Dr Ravi Singhal has studied nuclear physics over the past forty years. In this series of talks, he will introduce the various ideas for the general audience without assuming any previous scientific background. The talks are suitable for all to attend and they are free. Secondary school students are especially encouraged to come to the talks.

The ‘Science for All’ is managed by Dr. Singhal in partnership with Scottish Enterprise and Glasgow University. In previous talks, Dr Singhal has discussed the subjects of The Universe, Climate Change and Nano-technology. Further details about the programme may be obtained by contacting ektalks@yahoo.co.uk

The websites http://www.scienceforall.co.uk and http://ektalks.blogspot.com give current updates about the science awareness programme in East Kilbride.

Tuesday, 15 January 2008

Science For All Talks start in February.....

Atomic Nucleus and Nuclear Energy

Dr Ravi Singhal
Free Science Talks for Secondary Pupils & Adults
No Science Background Needed
11 am – 12 noon on Saturdays
16, 23 February; 1, 8 & 15 March 2008
James Watt Auditorium, E.K. Technology Park, G75 0QD
(Ample free parking on site)

Talks aimed at increasing public awareness of science, Dr. Singhal will look at the atomic nucleus. Ten thousand times smaller than the atom, the nucleus carries most of the mass. The first three talks will aim to answer some of the questions:

What is the nucleus made of?
How do we study the nucleus?
How is the nucleus held together?
What are nuclear fission and fusion?
How have nuclear applications benefited mankind?

The last two talks will look at the science of nuclear energy production. This is a topic of vigorous current debate in the U.K. and is of great public interest/concern – particularly in relation to limiting carbon emissions, securing energy supplies, nuclear waste management and safety.

The talks are designed for the general audience and no prior background in science is required. Secondary school students are especially encouraged to attend. The presentation promises to be visually attractive, entertaining and thought-provoking. The talks are free to attend.

In Partnership with: Physics Department, Glasgow University
Scottish Enterprise, Lanarkshire

Further Information: ekTalks@yahoo.co.uk