Physics Spring Term AP2 Flashcards
What is nuclear fusion?
the process by which two light atomic nuclei combine to form a single heavier one while releasing massive amounts of energy
hydrogen nuclei smash together to form helium
Where does nuclear fusion take place?
in the core of a star
Which part of an atom carries out nuclear fusion?
the nucleus
Why do stars shine?
the release energy (heat and light) into the universe
What are stars made of?
mostly hydrogen, with some helium and some other elements
What causes tides?
the moon’s gravity pulls the earth’s ocean towards it
Why are there 2 high tides?
The water on the earth’s far side is pulled less strongly than the earth so it gets ‘left behind’ therefore there is a tide on the earth’s far side as well as the side nearest to the moon
What is a solar eclipse?
a solar eclipse occurs when the moon passes between the sun and the earth
What is a lunar eclipse?
when the earth gets between the sun and the moon
Are there tides at the North/South poles?
yes but they are not as pronounced
How are stars formed?
gas and dust in nebulas (clouds of dust) are pulled together by gravity
this makes a protostar (like a baby star)
it officially becomes a star once nuclear fusion starts happening
What is a neutron star?
It’s what is formed when the star is too big to form a white dwarf and too small to form a black hole. It’s comprised of densley packed neutrons.
What is a supernova?
the colossal explosion of a star
What is a black hole?
a spherical region of space
What is a protostar?
A warm (few hundreds of degrees at most) cloud of gas and dust
What is a main sequence star?
when dust from a nebula becomes so hot nuclear fusion starts
What is a planetary nebula?
when the outer layers of a red giant formed from a low/medium sized star drift off
What is a white dwarf?
when the core of the (planetary nebula) star cools
What is a black dwarf?
when a white dwarf runs out of fuel
How are black holes formed?
After a large mass star explodes, the gravity of the mass is so strong that the gas is pulled inward into a smaller and smaller space until even light can’t escape it.
What is the boundary of a black hole called?
the event horizon
What are black holes surrounded by?
orbiting discs of gas and dust called accretion discs
(For planets) the bigger the mass, the bigger the?
the bigger the mass, the bigger the gravity
What colour are the cool stars? (cool as in heat)
they are red in colour
