Topic Thirteen Flashcards Preview

Abi Biology 2015 > Topic Thirteen > Flashcards

Flashcards in Topic Thirteen Deck (29):

Who or what gave us the idea of constellations?

Early civilisations gave us the idea of constellations.


Who have given us different ideas about the stars?

Different cultures have given us stories of the stars.


What do rock art paintings in Europe tell us?

They show that people have observed and recorded the movements of stars and planets for hundreds of years.


What early civilisations made records of astronomy?

The ancient Greeks, the Egyptians and Romans.


Which civilisation was very advanced in their knowledge of astronomy?

The Egyptians were very advanced and even made quite accurate calculations as to the distance to the sun, and to the size of the Earth itself.


Why did a number of early cultures have a sun god?

Early astronomers, who were also priests, saw that the sun was very important for life, since it made crops grow, and gave out heat and light.


What constellation is the smallest?

The Southern Cross or Crux is the smallest constellation.


What can the Southern Cross be used for?

It can be used to help people find their way.


What are the Plieades?

They are a group of stars in the constellation Taurus that disappear for a few months in winter.


How was the first telescope invented?

An eyeglass maker discovered that by placing two lenses in front of one another, he could see further.


How do telescopes work?

They work by collecting the light given off by stars.


What do telescopes do?

Telescopes help us to observe objects many miles away.


What are the two main types of telescopes?

Optical telescopes and radio telescopes.


What is the objective lens in a telescope?

The objective lens is the larger lens that collects and focuses the light from an object.


What is the eyepiece lens in a telescope?

The eyepiece lens is the lens nearest your eye in a telescope. It enables the light focused by the objective to be perceived as an image.


How do refraction telescopes work?

They work by bending the light towards the eyepiece lens.


How do reflection telescopes work?

They work by reflecting the light from stars, using mirrors.


What is magnification?

Magnification is how big a telescope makes an object look.


What is the equation to work out the magnification of a telescope?

You divide the focal length of the telescope by the focal length of the eyepiece.


What is SALT?

SALT is the South African Large Telescope. It is the largest telescope in the Southern Hemisphere. It is a reflecting telescope.


What makes the position of SALT optimal for a telescope?

The area has dark, clear skies and good weather conditions. It has low humidity.


What sometimes stops us from clear pictures of space from Earth?

The Earth's atmosphere often refracts the light from stars.


What is one of the most famous telescopes in space?

The Hubble telescope.


How do radio telescopes work?

They collect radio waves that stars, planets and other objects in space give out.


What is a basic design for a radio telescope?

They generally have a bowl or dish-shaped base for collecting radio waves.


What are good conditions for a radio telescope?

There must be minimal interference from cellphones and radio towers.


What is an array?

An array is a group of radio telescopes that are working together, which can collect a lot more radio waves, and are more efficient.


What are the two types of optical telescopes?

Telescopes that use reflection, and telescopes that use refraction.


What are good conditions for optical telescopes?

The weather must be clear
There must be no wind
The air should be dry
The humidity must be low
There must be no light pollution from cities, towns etc.
The telescope should be at a high altitude