The Sun

From Karnataka Open Educational Resources

Concept Map

Textbook

Karnataka state SCIENCE text book for class 9:Chapter-27 The Sun.

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Teaching Outlines

Main features of The Sun:Interior and outer structure, Drawing of structure of The Sun.

Manifestations of Solar activity:sun spots, solar wind, solar flares and prominences.

Kepler's laws of Planetary motion:3 laws of planetary motion.

Concept-1:Nature and main features of the Sun

  • Main features of The Sun
  • Manifestations of Solar activity.

Learning objectives

  • The Sun is an immense ball of gases nearly a million miles in diameter, with a mass of more than 300,000 times the mass of the Earth. This happens to be about a thousand times the mass and a thousand times the volume of Jupiter, so the Sun is, like Jupiter, about 30% denser than water. However, unlike Jupiter, which is made of liquid hydrogen and helium, the Sun is entirely gaseous. This difference is caused by the Sun's high temperature, which ranges from a low of 6000 Kelvins (about 10000 Fahrenheit) at the surface to a high of about 15 million Kelvins (almost 30 million Fahrenheit) in the center. These high temperatures tear any molecules or atoms of hydrogen and helium to pieces, and those pieces are much smaller than ordinary atoms, so even at very high densities the materials in the Sun are still gaseous.
  • Because of the Sun's high temperature and large size it radiates a tremendous amount of light and to a lesser extent, other kinds of electromagnetic radiation. It gives off approximately 400 trillion trillion watts (4 x 1026 watts) of power, which is created by thermonuclear reactions in its deep interior.
  • Despite its immense size, mass and brightness the Sun is actually a fairly average star. There are stars with more than a hundred times the mass of the Sun, and stars with as little as a few percent of its mass. Stars with up to a thousand times the diameter of the Sun, and as little as a hundredth of its diameter. Stars with as much as a few million times its brightness, and as little as one fifty-thousandth of its brightness. And in almost every other respect, whatever properties are discussed for the Sun there are stars with much larger or much smaller values than those which apply to the Sun.
  • Despite being a very average star, the Sun is of immense importance to us, because our lives depend upon its light and heat. Without it life on Earth would soon end. In addition, the Sun is very important to astronomers, because being by far the closest star, we can study it in far more detail than any other star.
  1. Explains the Nature of the Sun.
  2. Explains the main features of the Sun such as Outer and Internal structure of The Sun.
  3. Draws the diagram showing the structure of The Sun.
  4. Explains the reason for enormous energy output of The Sun.
  5. Explains reason for calling the Sun as the laboratory for studying the other stars.

Notes for teachers

Sun is the source of energy. Sun is the nearest star to us. It belongs to the milky way galaxy.

If you want to journey into sun look at this link here.

Activity No #

  1. Materials/ Resources needed
  2. Prerequisites/Instructions, if any
  3. Multimedia resources

http//https://en.wikipedia.org/wiki/Sunspot‎

  1. Website interactives
  2. Evaluation

Concept-2:Kepler's laws of planetary motion

  • Kepler's first law
  • Kepler's second law
  • Kepler's third law

Learning objectives

  • Kepler presented his first two laws of planetary motion in 1609 by using the notes of his predecessor TYCHO BRAHE and third law in 1619.
  • Kepler developed his laws empirically from observation, as opposed to deriving them from some fundamental theoretical principles. About 30 years after Kepler died, Isaac Newton was able to derive Kepler's Laws from basic laws of gravity.
  • Newton presented his law of universal gravitation as a case study of his laws of motion. All matter exerts a force, which he called gravity, that pulls all other matter towards its center. The strength of the force depends on the mass of the object: the Sun has more gravity than Earth, which in turn has more gravity than an apple. Also, the force weakens with distance. Objects far from the Sun won’t be influenced by its gravity.Hence all the planets of the solar system revolve around the SUN due to Strong gravitational force of the Sun.
  • Newton’s laws of motion and gravity explained Earth’s annual journey around the Sun. Earth would move straight forward through the universe, but the Sun exerts a constant pull on our planet. This force bends Earth’s path toward the Sun, pulling the planet into an elliptical (almost circular) orbit. His theories also made it possible to explain and predict the tides. The rise and fall of ocean water levels are created by the gravitational pull of the Moon as it orbits Earth.
  1. States Kepler's three laws of planetary motion.
  2. Explains Kepler's laws of planetary motion.

Notes for teachers

These are short notes that the teacher wants to share about the concept, any locally relevant information, specific instructions on what kind of methodology used and common misconceptions/mistakes.

Activity No #

  • Estimated Time
  • Materials/ Resources needed
  • Prerequisites/Instructions, if any
  • Multimedia resources
  • Website interactives/ links/ simulations
  • Process (How to do the activity)
  • Developmental Questions (What discussion questions)
  • Evaluation (Questions for assessment of the child)
  • Question Corner

Activity No #

  • Estimated Time
  • Materials/ Resources needed
  • Prerequisites/Instructions, if any
  • Multimedia resources
  • Website interactives/ links/ simulations
  • Process (How to do the activity)
  • Developmental Questions (What discussion questions)
  • Evaluation (Questions for assessment of the child)
  • Question Corner

Project Ideas

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Fun corner