Posted By: Shreyasi Bhattacharya
Class: VIII B
Dwarf Planets Facts…….
Planet Quiz…..
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1. Now that Pluto is no longer included, how many planets are there in the Solar System?
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2. What is the smallest planet in the Solar System?
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3. What is the largest planet in the Solar System?
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4. What is the hottest planet in the Solar System?
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5. The sixth planet from the Sun features an extensive ring system, what is the name of this planet?
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6. The chemical element uranium was named after what planet?
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7. What planet in the solar system is farthest from the Sun?
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8. What is the second smallest planet in the solar system?
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9. What planet is closest in size to Earth?
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10. The moon Titan orbits what planet?
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11. What planet is nicknamed the ‘Red Planet’?
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12. True or false? Neptune is larger than Saturn.
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13. The Galilean moons orbit what planet?
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14. What planet is closest to the Sun?
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15. What is the seventh planet from the Sun?
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16. True or false? Venus has more atmospheric pressure than Earth?
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17. Triton is the largest moon of what planet?
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18. What is the brightest planet in the night sky?
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19. What is the third planet from the Sun?
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20. Phobos and Deimos are moons of what planet?
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Planet Quiz Answers
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1. 8
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2. Mercury
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3. Jupiter
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4. Venus
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5. Saturn
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6. Uranus
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7. Neptune
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8. Mars
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9. Venus
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10. Saturn
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11. Mars
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12. False
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13. Jupiter
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14. Mercury
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15. Uranus
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16. True
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17. Neptune
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18. Venus
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19. Earth
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20. Mars
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Posted By: Shreyasi Bhattacharya
Class: VIII B
Amazing Facts on Comets………
A comet is a relatively small solar system body that orbits the Sun. When close enough to the Sun they display a visible coma (a fuzzy outline or atmosphere due to solar radiation) and sometimes a tail.
The coma is created as the comet gets closer to the Sun, causing water, carbon dioxide and other compounds to sublime (quickly changing from solid to gas) from its surface.
Comets are made of ice, dust and small rocky particles.
The name comet comes from the Greek word meaning ‘hair of the head’, it came from the Greek philosopher Aristotle who observed comets as ‘stars with hair’.
Short term comets (also known as periodic comets) have orbital periods of less than 200 years while long term comets have orbital periods of over 200 years.
Halley’s Comet
Halley’s Comet (or Comet Halley as it is also known) is the most well known comet.
It is known as a periodic comet (or short term comet) because the time it takes to orbit the Sun is less than 200 years.
Records of humans observing Halley’s Comet go back thousands of years, with appearances noted by Babylonian, Chinese and European star gazers.
It can be seen with the naked eye from Earth every 75 to 76 years (although the time period has between 74 and 79 years in the past).
It last appeared in the inner Solar System in 1986 and will return again sometime in 2061 (start charging your camera battery).
Halley’s Comet is named after English astronomer Edmond Halley who first determined its period of orbit. It was the first comet to be recognized as having a periodic orbit.
Halley’s Comet appearance in 1986 allowed researchers to investigate its make up more closely using spacecraft. While some previous theories were proven correct, other models were altered with the new information. For example, while earlier models predicted the comet to feature many volatile ices, the actual amount was less than first expected.
The tail and fuzzy glow you see around Halley’s Comet is known as a coma. It occurs when the comet gets close to the Sun and compounds such as frozen water and carbon dioxide sublime (rapidly change from solid to gas) from its surface.
While the coma over Halley’s Comet can stretch up to 100,000 km across, the nucleus is actually small, only around 15km (9.3 miles) long, 8km (5 miles) wide and 8km (5 miles) thick.
Comet Shoemaker-Levy 9
In July 1994, the Shoemaker-Levy 9 comet broke apart and collided with Jupiter. This event gave astronomers a unique opportunity to observe what happens when such a collision occurs.
The largest fragments were 2 km (1.2 mi) in diameter and struck Jupiter at a speed of around 60 km/s (37 mi/s). The impact scars were clearly visible for months after the impact.
Shoemaker-Levy 9 was originally located by astronomers Eugene M. and Carolyn Shoemaker and David Levy in March 1993.
Posted By: Shreyasi Bhattacharya
Class: VIII B
STORY OF THE UNIVERSE……..
Most astronomers believe the Universe began in a Big Bang about 14 billion years ago. At that time, the entire Universe was inside a bubble that was thousands of times smaller than a pinhead. It was hotter and denser than anything we can imagine.
Then it suddenly exploded. The Universe that we know was born. Time, space and matter all began with the Big Bang. In a fraction of a second, the Universe grew from smaller than a single atom to bigger than a galaxy. And it kept on growing at a fantastic rate. It is still expanding today.
As the Universe expanded and cooled, energy changed into particles of matter and antimatter. These two opposite types of particles largely destroyed each other. But some matter survived. More stable particles called protons and neutrons started to form when the Universe was one second old.
Over the next three minutes, the temperature dropped below 1 billion degrees Celsius. It was now cool enough for the protons and neutrons to come together, forming hydrogen and helium nuclei.
After 300 000 years, the Universe had cooled to about 3000 degrees. Atomic nuclei could finally capture electrons to form atoms. The Universe filled with clouds of hydrogen and helium gas.
Posted By: Shreyasi Bhattacharya
Class: VIII B
All the Thirteen Planets of our Solar System…………
Posted By: Shreyasi Bhattacharya
Class: VIII B
The Biggest Star in the Universe!!!!!!!!
Have a look at the Biggest Star in the Universe……….
Posted By: Shreyasi Bhattacharya
Class: VIII B
The Moon
Posted By: Shreyasi Bhattacharya
Class: VII B
Aurora
The Earth’s magnetic field funnels particles from the solar wind over the Polar Regions (due to the magnetic nature of the Earth). More than 80 kilometers above the ground, these collide with molecules in the atmosphere causing them to glow: green and pale red for oxygen and crimson for nitrogen. Auroras are caused by radiation from the sun, called solar wind, interacting with Earth’s magnetic field. Since the magnetic field is strongest near the poles, that’s the region where most auroras occur. Solar charged particles from the sun, which are normally radiated into space, sometimes get caught in the Earth’s magnetic field as they come into the upper atmosphere they react with other gases and produce colored lights The Earth’s magnetic field funnels particles from the solar wind over the polar regions (due to the magnetic nature of the Earth).
By – Karan Takalkar
VII A
Acids, Bases and Salts
The reaction of an acid with a base to produce only salt and water is called a neutralization reaction.
Acids
Acids are sour in taste.
If hydronium ions are found in a solution, the solution is acidic in nature. Hydronium ions are the only positively-charged ions (cations) formed when an acid dissolves in water. All the properties of an acid are due to the presence of these ions. The chemical formula of an hydronium ion is H3O1+.
An acid is known as a ‘proton donor‘.
Examples of Acids
Aqua Regia contains concentrated Nitric acid and concentrated Hydrochloric acid in the ratio 1:3. Aqua Regia means ‘Royal Water’ in Latin. It is used to dissolve noble metals like gold and platinum.
Milk contains lactic acid. Lactic acid is named after the Latin word ‘lac’, which means milk.
Vinegar is very dilute acetic acid. The vinegar used in cooking contains approximately 4% of acetic acid. The chemical formula of acetic acid is CH3COOH.
Sulfuric acid is used in the manufacture of many car batteries. It is also known as ‘Oil of Vitriol’. The chemical formula of Sulfuric acid is H2SO4.
Carbonic acid is responsible for the ‘fizz’ in soft drinks. The carbonic acid decomposes into Carbon dioxide bubbles. The chemical formula of Carbonic acid is H2CO3.
Ascorbic acid is the chemical name of Vitamin C. Deficiency of Vitamin C in the body may result in a disease known as scurvy. The chemical formula of ascorbic acid is C6H8O6.
Bases
Bases are bitter in taste and soapy to touch.
If hydroxyl ions are found in a solution, the solution is basic in nature. Hydroxyl ions are the only negatively-charged ions (anions) formed when a base dissolves in water. All the properties of a base are due to the presence of these ions. The chemical formula of an hydroxyl ion is OH1-.
A base is known as a ‘proton acceptor‘.
Examples of Bases
Antacids help to neutralize the acidity (of hydrochloric acid) in the stomach. They chiefly contain two bases, namely Magnesium hydroxide and Aluminum hydroxide. The chemical formula of Magnesium hydroxide and Aluminum hydroxide is Mg(OH)2 and Al(OH)3 respectively.
Sodium hydroxide is also known as ‘Caustic Soda‘. Its chemical formula is NaOH.
Potassium hydroxide is also known as ‘Caustic Potash‘. It is used in the manufacture of alkaline batteries. Its chemical formula is KOH.
Ammonia is a basic gas which is used in the manufacture of fertilizers such as Urea, Ammonium nitrate, and Ammonium sulfate. Ammonia is produced for commercial purposes by the Haber’s Process. When dissolved in water, Ammonia forms a base known as Ammonium hydroxide. The chemical formula of Ammonia is NH3.
Salts
A salt is defined as a compound formed by the complete or incomplete replacement of the hydrogen ion of an acid by a basic radical.
A normal salt is formed by the complete replacement of the hydrogen ion of an acid by a basic radical whereas an acid salt is formed by the incomplete replacement of the hydrogen ion of an acid by a basic radical.
Examples of Salts
Sodium sulfate is a normal salt whereas Sodium bisulfate is an acid salt.
Sodium sulfide is soluble in water whereas Copper carbonate, Lead chloride, and Barium sulfate are insoluble in water.
Sodium carbonate is used in the manufacture of detergents and glass.
Zinc sulfide is insoluble in water whereas Potassium phosphate, Ammonium carbonate, and Barium chloride are soluble in water.
Ammonium nitrate is used in the manufacture of fertilizers.
Posted By: Shreyasi Bhattacharya
Class: VII B
Did You Know??
What is dandruff?
Your skin constantly renews itself; dead cells from the scalp fall off as new cells from beneath them. Everyone loses skin cells in this way.
With dandruff the process is faster, so a greater number of cells are shed. This means the cells shed in clumps (flakes) that are big enough to be seen by the eye.
Flakes of dandruff are especially visible when they land on dark clothing. The scalp can also be itchy. The medical name for dandruff is pityriasis capitis, and it’s the most common condition of the scalp.
Many people think they get dandruff because their scalp’s too dry. They stop washing their hair with shampoo, or wash it less frequently, because they believe it makes the condition worse. This isn’t true.
Flaking only happens because of an increased turnover of skin cells or an infection of the scalp. It’s more common in children .
Dandruff is believed to be associated with an overgrowth of a fungus commonly found on the skin and scalp, called Malassezia (previously called Pityrosporum ovale).
Can dandruff be prevented?
It can be difficult to prevent dandruff completely, but it can be controlled. The condition may also improve as you get older.
By – Aarya Raina
VII D
PresidiumScienceAdda 