Physics (Y9) Flashcards
What is the heliocentric model?
This is the model we used today. It is when all the planets (including the earth) orbit the sun.
What are some reasons for the geocentric model?
-The ground did not seem to move
-The sun and moon did appear to move
-The stars also appeared to move
What are some reasons against the geocentric model?
-Sometimes the planets appeared to go backwards. This is called a retrograde motion.
In each date and location what are the ideas…
1)850BC-india-…
2)350BC-greece-…
3)200BC-greece-…
4)151-greece-…
5)1300-baghdad-…
6)1543-poland-…
1)The earth is in a motion around the sun
2)Aristotle describes the geocentric model in a book
3)Aristarchus describes the helocentric model in a book
4)Ptolemy publishes his revised geocentric model
5)Ibn al-shatir improves Ptolemy’s model
6)conpernicus publishes the heliocentric model
Explain some facts and theories about the big bang.
-Most scientists believed the universe began with the big bang
-All of space and time expanded from something smaller than an atom
-The universe has been expanding ever scince
-The big bang theory explains why galaxies are moving apart and why the galaxies that are futher away are moving faster
What astronomer made these observations about the galaxies moving?
An astronomer called Edwin Hubble made these observations about the galaxies moving away from us in 1929. The Hubble space telescope (HST) is named after him.
When did each of these events occur…
1)The Big Bang
2)The first star appears
3)Galaxies started to form
4)Solar System formed
1)14 billion years ago
2)13.65 billion years ago
3)13 billion years
4)4.5 billion years ago
What is the geocentric model?
People believed the earth did not move. They believed that the sun,moon,planets and stars all moved around (orbited) the earth.
What is the Big bang theory?
Scientists believed that every speck of energy in the universe was jammed into a very tiny point. This extremely dense point exploded with inimaginable force, creating matter and propelling it outwards to make billions of galaxies of our vast universe.
When and how did the solar system form?
Around 5 billion years ago a cloud of mostly hydrogen gas and dust collapsed in on itself. The cloud spun and the temperature increased leading to a protostar to begin to form at the centre. The planets formed from the spinning cloud of dusk. The gravity is greater nearer the star/sun causing dense material to be pulled in.
Name the rocky planets and what are they?
The rocky planets are the inner planets. Mercury,venus,earth and mars. Rocks and other dense material in the dust cloud tended to come together near the sun.
Name the gas giants and what are they?
The gas giants are the outer planets. Jupiter,satun,uranus and neptune. Gaseous substances gathered together futher away from the sun and formed the gas gaints.
What is a AU?
AU (astronomical unit) are used to measure the distance from the planets to the sun. 1AU= the distance from sun to earth (150,000,000km).
What are black holes?
A black hole is an area of space where gravity pulls sp much that even light cannot escape. The gravity is so strong because all the matter has been squished into a tiny space. They form when a star starts to die.
What is a light year?
The distance travelled by the speed of light in a year.
1 light year = 9,460,730,472,580,800m
What is a dwarf planet?
A dwarf planet is a planetoid that is to small to be considered a planet. (Pluto is an example)
What is a exoplanet?
A planet that orbits a star other than the sun
What is a planet?
Large objects in orbit around a star,but excluding comets and asteriods.
What is a risk assessment ?
There is a risk to any activity. When you do a risk assessment you consider the probability that something will happen, and the consequences if it did. Then you do your best to reduce the probability or change the consequence.
What are some risks when space travaling?
-injury to astronauts
-pollution to environment
-damage to orbiting satallites
-parachute failing to open
-Solar flare (raidiation)
-rocket exploding e.c.t.
How do satellites get into orbit ?
The satellite is attached to a rocket. Fuel is burned inside the rocket and pushes the waste gases out the bottom of it. There is the force of the rocket on the gases, and the force of the gases on the rocket. There is also forces between the rocket and the earth. When the force of the air on the rocket is bigger than the force of the earth on the rocket,it will take off.
What are satellites useful for?
Satellites are used for communication,monitoring the weather,studying the Earth and space,and so much more. For them to do the right job they must be put in the right type of Orbit.
What are some of the different types of orbits?
Geostationary orbit
Low earth orbit
Polar orbit
What is geostionary orbit?
-it takes 1 day to orbit earth
-it is always above a spot on the equator
-it is about 36,000km from earth
-a satellite in a geostationary orbit can broadcast television signials
