X2 consists of small notes on facts, culture, and history of physics in Persian. The texts are in the pdf format. To view them, Adobe (Acrobat) reader 5 or later is needed. Adobe reader can be obtained from Adobe reader download.

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X2 (2017)                                        back to mamwad
X2-124 (2017/05/29) pdf The age of the universe, and the catastrophe of 
                        the estimation of the cosmological constant

X2-123 (2017/04/17) pdf The power and the life time of a white dwarf

X2-122 (2017/02/27) pdf Wheat as food

X2-121 (2017/01/28) pdf Pluto's surface temperature

X2 (2016)                                        back to mamwad
X2-120 (2016/11/30) pdf If the arctic ice melts

X2-119 (2016/10/31) pdf If the moon becomes attached to the earth, what would be the length of the day?

X2-118 (2016/08/27) pdf How much air is needed to survive?

X2-117 (2016/07/29) pdf Cooling, using evaporation

X2-116 (2016/05/30) pdf The compact object in the center of the Milky Way

X2-115 (2016/04/29) pdf The speed of water waves

X2-114 (2016/02/28) pdf The gravitational potential energy of a mountain

X2-113 (2016/01/29) pdf Archimedes and moving the earth

X2 (2015)                                        back to mamwad
X2-112 (2015/11/30) pdf Energetic cosmic particles

X2-111 (2015/10/30) pdf Quantum mechanics and Iran, III: relativistic quantum mechanics

X2-110 (2015/08/29) pdf Internal heating of planets

X2-109 (2015/07/30) pdf The habitable zone, and the evolution of the sun

X2-108 (2015/05/29) pdf Remaining young in the gravitational field

X2-107 (2015/04/30) pdf The impulse, force, and pressure due to the rain

X2-106 (2015/02/24) pdf The water in the clouds

X2-105 (2015/01/26) pdf The minimum of the melting temperature of ice

X2 (2014)                                        back to mamwad
X2-104 (2014/11/28) pdf Revolution of the sun around the galactic center

X2-103 (2014/10/30) pdf Melting of ice, and convection

X2-102 (2014/08/25) pdf Freezing water, and cracking vessel

X2-101 (2014/07/26) pdf Perspiration

X2-100 (2014/05/30) pdf Buoyancy of the human body

X2-099 (2014/04/26) pdf The density of the rocky planets

X2-098 (2014/02/22) pdf Reducing the time needed to cook an egg

X2-097 (2014/01/31) pdf Evaporating water, raising water

X2 (2013)                                        back to mamwad
X2-096 (2013/11/29) pdf Change of the carbon dioxide ratio in the atomsphere

X2-095 (2013/10/30) pdf Which is hotter, boiling water or water vapor?

X2-094 (2013/08/31) pdf Constant angular velocity in Keplerian orbits

X2-093 (2013/07/30) pdf Quantum mechanics and Iran, II: modern quantum mechanics

X2-092 (2013/05/30) pdf The intensity and the effective intensity of the sunlight

X2-091 (2013/04/29) pdf The volume difference of liquid and gas, and the latent heat of vaporization

X2-090 (2013/02/28) pdf The laser reflected from the lunar surface

X2-089 (2013/01/30) pdf Time needed to cook an ostrich egg

X2 (2012)                                        back to mamwad
X2-088 (2012/11/29) pdf Planck mass

X2-087 (2012/10/30) pdf The boling point of the mixture of two immiscible fluids

X2-086 (2012/08/31) pdf Apparent diameters of heavenly bodies

X2-085 (2012/07/31) pdf The electric charge does not depend on the velocity

X2-084 (2012/05/30) pdf The uncertainty, and an old model of the nucleus

X2-083 (2012/04/27) pdf Ultrasonic humidifiers

X2-082 (2012/02/29) pdf A supernova as luminous as the full moon

X2-081 (2012/01/28) pdf Cooling of the erarh, and age of the earth

X2 (2011)                                        back to mamwad
X2-080 (2011/11/30) pdf Thin tubes and fluid current

X2-079 (2011/10/30) pdf Multipole radiation and the life of excited electron states

X2-078 (2011/08/10) pdf Escaping the increasing power of the sun

X2-077 (2011/07/29) pdf The focal length of thin lenses

X2-076 (2011/05/30) pdf Scattering of the sunlight in the earth's atmosphere

X2-075 (2011/04/30) pdf The angle of the rainbow

X2-074 (2011/02/25) pdf Threshold of vision

X2-073 (2011/01/27) pdf The smooth surface of a neutron star

X2 (2010)                                        back to mamwad
X2-072 (2010/11/26) pdf Magnetar

X2-071 (2010/10/30) pdf Motion with a fixed speed, in a fixed direction relative to the north

X2-070 (2010/08/28) pdf The collision which created the moon

X2-069 (2010/07/28) pdf The magnetic force felt by nonmagnetic materials

X2-068 (2010/05/28) pdf The fastest and slowest living creatures

X2-067 (2010/04/30) pdf Quantum mechanics and Iran, I: old quantum mechanics

X2-066 (2010/02/27) pdf Turning off LEDs to save electricity?

X2-065 (2010/01/29) pdf Melting temperature versus pressure

X2 (2009)                                        back to mamwad
X2-064 (2009/11/28) pdf Rotation of stars

X2-063 (2009/10/29) pdf The speed of propagation of the electric field, and the speed of charges

X2-062 (2009/08/27) pdf Maximum of the speed in running

X2-061 (2009/07/30) pdf Sharpness of phase transition

X2-060 (2009/05/30) pdf Escaping the gravitational field

X2-059 (2009/04/24) pdf Relativity and Iran

X2-058 (2009/02/27) pdf Energy released in an earthquake

X2-057 (2009/01/22) pdf Tunneling probability for electron and proton

X2 (2008)                                        back to mamwad
X2-056 (2008/11/30) pdf Adiabatic, isothermal, and evanescent sound

X2-055 (2008/10/31) pdf Surface tension in the nucleus

X2-054 (2008/08/29) pdf Thermodynamics and Iran, III: 
                        Statistical mechanics

X2-053 (2008/07/28) pdf Moon's halo, and water droplets

X2-052 (2008/05/31) pdf The electric field of the earth

X2-051 (2008/04/29) pdf The energy of rain

X2-050 (2008/02/29) pdf Are green leaves optimum for photosynthesis?

X2-049 (2008/01/31) pdf Density of elements

X2 (2007)                                        back to mamwad
X2-048 (2007/11/09) pdf Energy saving: turning off a lamp, 
                        or changing it

X2-047 (2007/10/13) pdf Energy released in the collision of 
                        a heavenly body with the earth

X2-046 (2007/08/10) pdf Thermodynamics and Iran, II: 
                        Clausius and Kelvin

X2-045 (2007/07/11) pdf Development and the price of goods

X2-044 (2007/05/31) pdf Multi-question quiz

X2-043 (2007/04/29) pdf Changing scales versus time

X2-042 (2007/02/28) pdf Sound and the amplitude of the 
                        displacement of the air molecules

X2-041 (2007/01/19) pdf Are all chemical reactions incomplete?

X2 (2006)                                        back to mamwad
X2-040 (2006/11/24) pdf Desalination of water: 
                        reverse osmosis versus distillation

X2-039 (2006/10/12) pdf Power consumption in the world, 
                        and the water of the oceans

X2-038 (2006/08/04) pdf Thermodynamics and Iran, I: 
                        Rumford, Carnot, and Joule

X2-037 (2006/07/06) pdf Old cars and fuel consumption

X2-036 (2006/05/19) pdf The magnetic fields of planets and stars

X2-035 (2006/04/02) pdf Windows and energy consumption

X2-034 (2006/02/24) pdf Elecetromagnetics and Iran, III: 

X2-033 (2006/01/06) pdf Why there are no very-large animals
                        on the earth?

X2 (2005)                                        back to mamwad
X2-032 (2005/11/25) pdf The nucleons and the photons of the universe

X2-031 (2005/10/07) pdf The eye, the photographic film, 
                        and the digital camera

X2-030 (2005/08/31) pdf Swimming in heavy water

X2-029 (2005/07/27) pdf The power of the stars

X2-028 (2005/05/27) pdf Chemical energy, nuclear energy

X2-027 (2005/04/26) pdf The power a human needs to survive

X2-026 (2005/02/28) pdf Molecular distances and energies, 
                        and the bulk modulus

X2-025 (2005/01/15) pdf Elecetromagnetics and Iran, II: 

X2 (2004)                                        back to mamwad
X2-024 (2004/11/12) pdf The tidal effect of the Moon on the Earth, 
                        and the change of the sidereal day

X2-023 (2004/10/15) pdf Water wasted due to faulty faucets in Tehran

X2-022 (2004/08/25) pdf Complexity of the living organisms and galaxies

X2-021 (2004/07/31) pdf Solar energy, and the world's energy consumption

X2-020 (2004/05/08) pdf Elecetromagnetics and Iran, I: 
                        the electrostatics of Coulomb and Poisson

X2-019 (2004/04/10) pdf Density of the universe at different scales

X2-018 (2004/02/14) pdf The carbon dioxide emmited by human into the atmosphere

X2-017 (2004/01/12) pdf Global warming, and the rise of ocean levels

X2 (2003)                                        back to mamwad
X2-016 (2003/12/13) pdf Galileo and the Leaning Tower of Pisa

X2-015 (2003/10/31) pdf The number of the nucleons of the observable universe

X2-014 (2003/09/24) pdf The gravitational radiation

X2-013 (2003/07/28) pdf The surface tension, and the latent heat of evaporation

X2-012 (2003/06/20) pdf The resolving power of the eye, and the heavenly bodies

X2-011 (2003/04/29) pdf Birth of the new science and Iran, III: 
                        from Lagrange to Hamilton

X2-010 (2003/03/21) pdf Cloud, rain, hailstone

X2-009 (2003/01/31) pdf The nearest neighbor of the Earth (after the Moon)

X2 (2002)                                        back to mamwad
X2-008 (2002/12/25) pdf Birth of the new science and Iran, II: 

X2-007 (2002/10/22) pdf Birth of the new science and Iran, I: 
                        from Kopernik to Galileo

X2-006 (2002/08/06) pdf The history of the oblateness of the earth

X2-005 (2002/07/14) pdf The lightning

X2-004 (2002/05/20) pdf Birth of the matrix mechanics in the second half of 1925

X2-003 (2002/04/09) pdf Heisenberg, Born, and Pauli

X2-002 (2002/02/22) pdf Power consumption per capita, and production per capita

X2-001 (2002/01/06) pdf The industrial revolution in terms of the spinning machine