SciencewithD

CHANDRAYAAN 2 CHANDRAYAAN 2 Chandrayaan 2 is an Indian lunar mission , it is the world first mission to land on the SOUTH POLAR region of the moon.  The mission  Chandrayaan 2 was approved by Prime minister Dr Manmohan Singh 18 Sept, 2008. Chandrayaan 2 was launched on 22 July, 2019. GSLV Mk-III launcher was used for this mission, which is completely Indigenous. The Chandrayaan 2 mission is very important for India as it is first attempt to soft landing on the lunar surface.  India would become the first country to do soft landing on Moon's south polar region. And 4th ever country to do so. The success of this mission will also boost up the India first ever Maned Mission on Moon. Chandrayaan 2 will land on by soft landing on lunar south polar region on 2 Sept, 2019. Chandrayaan 2 has Lander -'Vikram' named after 'Dr Vikram A Sarabhai' the Father of Indian Space Programme and Rover - 'Pragyan' means 'Wisdom' in language Sanskrit...

Traffic Light Signals When  We all have stuck in traffic jam,w e wonder how these light changes ? Does some person change the light watching the traffic or they automatically change?  Traffic lights is a set of automatic,coloured lights for controlling traffic. Traffic lights are signaling devices positioned at road intersection, pedestrian crossing , and other locations to control the flows of traffic. Traffic lights was initially designed for railway system. In 1830's the signal used for railway is  Red-Stop  ,  Green - Caution  and  White - Go . This system was not safe as white colour is not visible in night with stars at horizon or with white background  . In 1914 a  red lens  was fall from a signal and indicate  White-Go  result in a huge train tragedy. After that  white  colour is replaced by  Green  and  Green  by  Yellow  for caution. The world's first road traffic...

ISRO CHANDRAYAAN 1  CHANDRAYAAN 1 Chandrayaan 1 was the first Moon mission of India. ISRO's CHANDRAYAAN 1 mission was announced by Prime Minister Atal Bihari Vajpayee  on 15 Aug 2003. It takes five year to launch the mission from  the Satish Dhawan Space Centre at Sriharikota On  22 nd  October, 2008. Cost of Chandrayaan 1 project was ₹ 386 crore. Launch mass of the spacecraft was 1380 Kg. Launch vehicle used for mission was  PSLV-C11 The spacecraft was orbiting around the Moon at a height of 100 km from the lunar surface for chemical, mineralogical and photo-geologic mapping of the Moon. Mission Life was expected to be 2 years but it works 11 months (approx) fulfill 95% mission objective, before it lost on lunar surface. On 14 November, 2008 Chandrayaan 1 crashes near the lunar south pole - confirms  the presence of water molecules on the Moon's surface. 28th August, 2009 End of Chandrayaan 1 mission.

TRAFFIC LIGHT SIGNALS Traffic lights   is a set of automatic,coloured lights for controlling traffic. Traffic lights are signaling devices positioned at road intersection, pedestrian crossing , and other locations to control the flows of traffic. We all have stuck in traffic jam and observed the traffic lights which give us signal :           Red - Stop,when to stop          Yellow (Amber) - Caution , go slow             Green -go,  move    by changing colour.  What is the reason behind the use of  Red  ,  Yellow  and  Green in traffic light signals ? Red   was considered as the signal of danger from ages due to colour of  Blood  and  Fire since long. Red colour can be seen from   large distance due to its longest wavelength in visible spectrum and less scattering character. Yellow   has wav...