Grade Nine Science

Space Unit

• http://www.youtube.com/watch?v=SWOoV4b49SI

What can we see in the sky?

• What are some things that we can see in the sky?

• Something that people have noticed and documented throughout time is that there are patterns in what we see in the sky.

• Constellations

• North Star

• Moons

• Planets

• The study of what is beyond Earth is called Astronomy.

Star Constellations

• Groups of stars that seem to form shapes and patterns are called constellations.

• Some stars look as though they are close together when some are really much farther from Earth than others.

• Constellations have been used for thousands of years as calendars, timekeepers and direction finders for travellers.

Constellations

• http://www.youtube.com/watch?v=uKXBtWHExwQ

• The solar system consists of our sun and all the objects that travel around it.

• Planets and moons are nonluminous. They do not emit their own light. We can see them in the sky only when the light from the Sun reflects off them towards Earth.

• Only 5 of the planets in our solar system can actually be seen with an unaided eye: Venus, Mars, Jupiter, Saturn and Mercury.

How big is the universe

• http://www.youtube.com/watch?v=Zr7wNQw12l8

What is the difference between Stars and Planets?

Feature Planet StarLocation : In the solar system Far beyond the solar

system.

Distance from Earth: Fairly near Very far

Real Size: Smaller than most stars Usually larger than planets

Reason why we see object:

Reflects light from the sun Emits its own lights.

Surface Temperature: Usually cool or very cold Very hot

What is the object made of:

Usually rocks or gases. Gases under high pressure and temperature.

Long-term observable feature

Very slowly wanders through constellations

Appears to move through sky as part of a constellation.

What sound does the Earth make

• http://www.youtube.com/watch?v=5AVHXMLDvWA&feature=related

Sound of the Sun

• http://www.youtube.com/watch?v=pGwDdTZBAEY&feature=related

The Sun: An Important Star

• The sun provides us with the energy needed by all plants and animals on Earth

• It’s gravitational pull keeps us in our steady orbit.

• Because the Sun is the closest star to Earth, it is the brightest object in the sky. It gives off so much light energy that you cannot see the other stars until the Sun has set.

• The Sun’s energy comes from a process called Nuclear Fusion.

• Nuclear Fusion occurs because inside the Sun the temperature and pressure are so high that substances fuse (join together) to form new substances.

• In this process, large amounts of heat, light and other forms of energy that travel out from the Sun through Space.

• Every second the Sun makes more energy than humans have used throughout our entire history.

• Scientists have predicted that the Sun has been producing energy for 5 billion years and predict that the Sun will continue producing energy for about another 5 billion years.

Parts of the Sun

• Core – where nuclear fusion produces the Sun’s energy (temp of 15 million degrees C and enormous pressure)

• Radiative Zone – first layer that surrounds the core. Energy may take a million years to reach the next zone.

• Convective Zone – hotter substances rise as colder substances fall. Energy moves outward to the photosphere.

Parts of the Sun

• Photosphere – surface of the Sun (avg. temp of 5500 degrees C) and Sun Spots occur here.

• Chromosphere – the inner atmosphere of the Sun (60,000 degrees hotter than photosphere).

• Corona – thin outer layer of the solar atmosphere – gleaming white, halo-like – that extends millions of km into space.

Parts of the Sun

• Sun Spots – dark spots appearing on the surface that are cooler than the area surrounding them.

• Solar Flare – gases and charged particles expelled above an active sunspot.

• Solar Prominence – low energy gas eruptions from the Sun’s surface that extend thousands of km into space.

Aurora Borealis/Aurora Australis

• Solar flares emit charged particles, which travel much slower than light.

• When these particles reach Earth they are focused by the Earth’s magnetic field, at the north and south poles.

• These charged particles produce the Northern Lights and Southern Lights.

Characteristics of Stars

• The color of stars tell us something about their temperature.

• A relatively cool star glows red.

• A very hot one glows a bluish-white or even blue.

Characteristics of Stars - ColourColour Temperature Range

(degrees C)Example(s)

Blue 25 000 – 50 000 Zeta Orionis

Bluish-White 11000 – 25 000 Rigel, Spica

White 7500 – 11 000 Vega, Sirius

Yellowish-White 6000 – 7500 Polaris, Procyon

Yellow 5000 – 6000 Sun, Alpha Centauri

Orange 3500 – 5000 Arcturus, Aldebaran

Red 2000 – 3500 Betelgeuse, Antares

• Stars the size of the Sun or smaller are called Giants.

• Stars with masses 10 times or more larger than the Sun’s become Supergiants.

• A star the size of the Sun or smaller is said to have “died” when the nuclear reactions die down, the core shrinks and the outer layers of the star drift away. This becomes a dwarf star.

• Dwarf stars are stars with a higher temperature than red or yellow stars.

Characteristics of Stars

Characteristics of Stars

• Stars are also classified by their brightness.

• There are six categories, with the brightest stars called first magnitude and the faintest stars called sixth magnitude stars.

• Apparent Magnitude – how bright a star appears to you.

• Absolute Magnitude – actual amount of light given off .

Stars• A spectroscope is an instrument used by

astronomers to look at the light given off by the Sun and other stars.

• This device splits light into a pattern of colors so we can see them as separate lines of color.

• It can also tell what chemical elements make up a star, how much of each element each star contains, the temperature of a star and the direction the star is moving.

The Life of a Star

• Stars follow a predictable series of stages: they are born, they develop and die.

• Gravity is the force that pulls objects towards each other. The more mass that an object has, the more gravity it exerts.

The Sun has stronger gravity than Earth.

The force gets smaller as the distance between objects increases.

How do Stars form? • All stars begin their lives in nebulas.

• Nebulas are huge clouds of dust and gases, mainly hydrogen and helium.

• Dust and gases swirl around, breaking into clumps and contracting because of gravitational forces.

• As the dust and gasses swirl around they become bigger and their gravitational force becomes stronger.

How do Stars form?

• More particles begin to pack together and eventually the clumps are dense and hot enough for nuclear fission to start.

• No two stars are the same.

Supernovas

• A supernova is an enormous explosion that occurs at the end of a large star’s life.

• By this stage the star has used up the fuels needed to produce energy by the process of nuclear fusion.

Death of a Star

• http://www.youtube.com/watch?v=vCMXV8j2GtE

• http://www.youtube.com/watch?v=ysJ4Nj33rIo&feature=related

Neutron Stars• When a star is about 10 times the mass of

the Sun dies, the resulting core is called a neutron star. This star is composed of neutrons.

• A Pulsar is a type of a neutron star that emits pulses of very high radio waves.

• Pulsars are very small, about 20 km in diameter and very dense with the mass of a normal star.

Black Holes

• When a star about 30 times the mass of the Sun dies, the resulting core is called a black hole.

• A black hole is a small, very dense object with a force of gravity so strong that nothing can escape from it.

• Even light cannot be radiated away from its surface.

How big is the Sun?

The Sun Compared to Other Stars

How big is the sun

• http://www.youtube.com/watch?v=e5WnXI3Ycs0

What is the Universe?

• What things do we consider to be in the Universe?

The universe is everything that exists, including all matter and energy everywhere.

The Solar System

• What planets make up our solar system?

• (In order from the sun) , Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto (dwarf planet).

• The planets revolve around the Sun in paths called orbits.

• The orbits of most planets are nearly circular, with the Sun at the center of each orbit.

• The period of time for one revolution around the sun is called one orbital period.

• The earth’s orbital period is about 365 days.

• The earth’s rotation around its axis once every 24h causes our day and night cycle.

Earth’s Rotation

• The Earth rotates (spins) on an axis.

• It takes 24 hours to do one rotation around its axis.

• This motion causes most stars, sun and moon to appear to rise in the east and set in the west.

• The Earth’s axis is an imaginary line that connects the North Pole to the South Pole.

Earth’s Revolution

• The Earth’s Revolution is the motion of one object travelling around another.

• It takes Earth one year to travel and revolve in a circle around the sun.

• This allows us to see different stars and constellations during different seasons.

• The angle of the Earth’s axis and the Earth’s Revolution causes the different seasons.

Seasons

• http://www.youtube.com/watch?v=WLRA87TKXLM&feature=related

• The order from biggest planet to smallest is as follows.

• The largest planet is Jupiter. It is followed by Saturn, Uranus, Neptune, Earth, Venus, Mars, Mercury, and finally, tiny Pluto (a dwarf planet). Jupiter is so big that all the other planets could fit inside it.

The Inner vs. Outer Planets

• The inner planets (those planets that orbit close to the sun) are different from the Outer planets (those planets that orbit farther from the sun).

• The inner planets are: Mercury, Venus, Earth, and Mars. They are relatively small, composed mostly of rock, and have few or no moons.

• The outer planets include: Jupiter, Saturn, Uranus, Neptune, and Pluto (a dwarf planet). They are mostly huge, mostly gaseous, ringed, and have many moons (again, the exception is Pluto, the dwarf planet, which is small, rocky, and has one large moon plus two tiny ones).

• The planets of the solar system are made up of different combinations of chemical elements which is why no two planets are the same.

• Scientists have determined that throughout the solar system there are four common elements: hydrogen, helium, oxygen and carbon.

• These common elements are found under high pressure on the Sun and on the four largest planets.

Mercury

• Closest planet to the Sun.

• Recieves 10 times the amount of sunlight than Earth giving it 400 degrees celsius daytime temperatures.

• It has no atmosphere to trap heat so nighttime temperatures fall to –180 degrees celsius.

• Has craters all over planet.

Venus • Has a thick atmosphere that can reflect sunlight. • Brightest planet in the sky.• Second planet from the Sun.• Atmosphere is mainly made of carbon dioxide.

This gas acts like the glass of a greenhouse, keeping the surface temperatures high enough to melt lead.

• Venus is hard to explore because of its thick atmosphere.

Earth

• Third planet from the Sun.

• Atmosphere mainly contains nitrogen, oxygen, and water vapour.

• There is also a small amount of ozone that filters out some of the Sun’s radiation but lets enough through for life on Earth.

• Water covers 70% of Earth.

Mars

• Fourth planet from the Sun.

• Called the Red Planet because of the reddish color of its soil.

• Space Probe, Pathfinder, landed on Mars in 1997 and provided us with first hand photos of the planet.

• Evidence that Mars once had volcanoes, glaciers, and floods of water.

Jupiter

• Fifth planet from the sun.

• Largest of all planets.

• 11 times the diameter of Earth.

• Has a giant red spot where huge hurricanes form fed by constant high winds.

• Has 63 moons.

• Has orbiting rings of rock.

Saturn

• 6th planet from the sun

• Second largest planet.

• Atmosphere is cloudy because of its quick rotation.

• Has over 1000 separate rings.

• Average temperature is – 180 degrees Celsius.

Uranus

• 7th planet from the Sun.

• 4 times the size of Earth.

• Rotates on its side.

• Atmosphere is mainly made up of hydrogen with some helium and methane.

• Has winds that blow up to 500 km/ h.

• Takes 84 years to complete one orbit.

Neptune

• 8th planet from the Sun.

• First planet to be located by mathematical predictions.

• Orbits the Sun every 165 years.

• 4.5 billions km away from the Sun.

• Windiest planet 1000+ km/h

• Made mainly of ice

• http://www.youtube.com/watch?v=29wfzotaBIg

Pluto

• The International Astronomical Union (IAU) formally downgraded Pluto from an official planet to a dwarf planet.

• According to the new rules a planet meets three criteria: it must orbit the Sun, it must be big enough for gravity to squash it into a round ball, and it must have cleared other things out of the way in its orbital neighborhood.

• Pluto takes 248 years to orbit the Sun.

Planetary Moons

• Large natural objects that revolve around planets are called satellites or moons.

• The moon we have orbiting Earth has no atmosphere.

• 1610 Galileo was the first person to see four of Jupiter’s moons.

Planetary Moon Count in 2008Planet Number of known

moons

Mercury 0

Venus 0

Earth 1

Mars 2

Jupiter 63

Saturn 60

Uranus 27

Neptune 13

Pluto 3

• http://www.windows.ucar.edu/tour/link=/our_solar_system/moons_table.html

Asteroids

• rocky objects that travel throughout space.

• They are usually smaller than planets but larger than meteorites.

• Between Mars and Jupiter there is ring of asteroids called an asteroid belt.

• 1937 an asteroid named Hermes came within 800,000 km of Earth.

• Asteroids are rich in minerals which humans may have to mine someday.

Meteoroid • A lump of rock or metal that is trapped by the

Earth’s gravity and pulled down through the Earth’s atmosphere.

• As it falls it rubs against the molecules of the air causing friction. This friction causes the meteoroid to become hot and vaporize.

• This produces a bright streak across the sky.

• If the object is large enough to hit the ground before totally vaporizing, it is called a Meteorite.

Comets

• A comet is a chunk of frozen matter that travels in a very long orbit around the Sun.

Distances in Space

• Distances in space are very large, so scientific notation is used to abbreviate these large measurements.

• Using this notation, a number is written with a digit between 1 and 9 before the decimal, followed by a power of 10.

How are Distances Measured in Space?

• To measure long distances with as much accuracy as possible, they use the largest baselines available.

• One way that scientists measure distances in space is to use the diameter of the Earth. This method could be used to determine the distance to the moon or a nearby planet.

• The largest baseline available is the diameter of the Earth’s orbit. This is used to help scientists calculate distances to the stars nearest to our solar system.

• The distance from our Sun to the next nearest star that you can see without a telescope is about 4.1 x 1013 km. This star is called Alpha Centauri.

• The light year is another measurement of distance that scientists use.

• A light year is the distance that light travels in one year.

• Light travels at about 300, 000 km / second.

• In one year it can travel 9.46 x 1012 . So the distance to the nearest star is 4.3 light years away.

Probes to the Planets

• A space probe is an unpiloted spacecraft sent to explore parts of the solar system beyond Earth.

• The probe collects information and transmits it back to Earth.

Hubble Telescope

• Part 1

http://www.youtube.com/watch?v=SpkrVw_E6Nw&feature=related

Part 2

http://www.youtube.com/watch?v=upXTZE57Z5U&feature=related

• Part 3

• http://www.youtube.com/watch?v=xt9Bvc8s_d0&feature=related

• Part 4

• http://www.youtube.com/watch?v=1_9gsFcKh9I&feature=related

• Part 5

http://www.youtube.com/watch?v=gnCvHnlNT7c&feature=related

Part 6

http://www.youtube.com/watch?v=-PwkW76jR1w&feature=related

• Part 7

http://www.youtube.com/watch?v=fqYshf-jc7U&feature=related

Part 8

http://www.youtube.com/watch?v=23MXsnpC-5Y&feature=related

Pictures from the Hubble

• http://www.youtube.com/watch?v=-_Fs8oIdD7o&feature=fvw

Hubble Deep Field

• http://www.youtube.com/watch?v=mcBV-cXVWFw