School Certificate Science MARATHON (3 Viewers)

[Riot09]

What is the big bang theory and what are the possible fates?

the big bang a thoery relating to the origin of the universe,the big bang theory states that 13.7 billion years ago the univese exploded from a singularity (a point is space-time where there is infinite density) into energy and then started accelerating.

possible fates.

most likely heat death:where all the suns die out therefore no heat and everyone dies

the big rip:where the universe keeps on accelerating untill the universe rips apart,by the universe i mean atoms,matter everything-its like paint dots on a ballon and if you blow into the balloon the distance between the dots becomes greater just imagine that but with the atoms of youre body being ripped apart at the quantum level.

the big crunch: if the universe has enough mass then it will collapse back on itself.

dont fret this will happens billions of years from now.

 

[Riot09]

What was the width of the universe during the inflationary period?

Inflation is a general term for models of the very early Universe which involve a short period of extremely rapid (exponential) expansion, blowing the size of what is now the observable Universe up from a region far smaller than a proton to about the size of a grapefruit (or even bigger) in a small fraction of a second.

 

[Riot09]

astrophysics 101

distance in space is measured in light years.

black hole-is a body with an extremely high density,found in outer space.its gravity is so powerful not even light can escape it,hence black hole

galaxy-is made up of millions of stars,gas and dust held together by gravitational "force"

redshift-when object moves further away waves get longer

blueshit-when objects move closer waves get shorter

the doppler effect-is the same thing but for sound.

geocentric model of the heaven-proposed by ptolemy then propagetd by aristotle and believed in by the western civilisation christianity untill around the 16th century.

-nicalus copppernicosroposed that the earth moved around the sun,ironic because he was a church-lawer (forgot the word)

-galileo revivied heliocentrism by the use of his telescope and publishe dhis ideas.

slowly people started to believe him.

the big bang theory is supported by the red shift and cmbr (cosmic microwave backround radiation,which is 1% of the static on youre aerial t.v's)

however believing in the origin universe to be the big bang without absolute proof is like the same as believing in god without absolute proof so there should be no double standard.on either side.

a thoery is not a law which means it is not complete and can be modified or rejected with accord to empirical evidence

 

[Riot09]

theres only like 1 question on astro-physics anyway.

 

[Riot09]

what is difference between current and voltage

 

[muzeikchun852]

what is difference between current and voltage

voltage is the potential difference/the energy needed to move around a circuit
current is the electrical force pushing around the circuit/flow of electrons

question: wat is a reflex action?

 

[supre]

voltage is the potential difference/the energy needed to move around a circuit
current is the electrical force pushing around the circuit/flow of electrons

question: wat is a reflex action?

its an voluntary response by human body eg when u move ur hand from a hot surface.

My question: describe the changes that occur to a star over time.

 

[Freestyler94]

Its actually an involuntary response.

 

[Mudkip94]

My question: describe the changes that occur to a star over time.

They expand and become red giants then the outer layer goes away and they become white dwarfs then when they stop shining they become black dwarfs. Stars which are massive become red supergiants (after becoming a red giant) and explode in a supernova. If the core survives a supernova it becomes a black hole.

 

[Mudkip94]

My Question: What is the temperature of CMBR (Cosmic Microwave Background Radiation)?

 

[muzeikchun852]

My Question: What is the temperature of CMBR (Cosmic Microwave Background Radiation)?

cosmic background radiation is 3 kelvin (-270 degrees). the heat present at the time of the big bang. at this temperature the energy would be in teh form of microwaves.

question: name the equation for neutralisation, acid and metal, acid and carbonate.

 

[Mudkip94]

question: name the equation for neutralisation, acid and metal, acid and carbonate.

Acid + Metal --> Salt + Hydrogen

Acid + Carbonate --> Salt + Carbon Dioxide + Water

 

[silence--]

also

neutralisation: acid + base --> salt + water

err...question: State Newton's third law of motion and give an example of where you can see this.

 

[Mudkip94]

err...question: State Newton's third law of motion and give an example of where you can see this.

''To every action there is always an equal and opposite reaction: or the forces of two bodies on each other are always equal and are directed in opposite directions''

This can be seen in firearm recoil.

My Question: What is the most 'majorest' greenhouse gas and what makes a greenhouse gas effective?

 

[Riot09]

iv'e seen a question like this before but ill give it a shot.

carbon dioxide and the property that makes a greenhouse gas effecvtive is that it traps heat in.

 

[Riot09]

identify and give an example of a method to filter a mixture.

 

[hermand]

precipitate in a solution, filter out with filter paper and a funnel. also, to ensure complete purity in the filtrate, dry out in an oven or in a warm place.

what is dna?

 

[Mudkip94]

what is dna?

Deoxyribonucleic acid, has instructions which do stuff.

 

[Riot09]

why does my signature change to my profile picture and then after i edit a post it changes to my current signature then after i leave and come back it changes to the profile picture again?

and a dna molecule make up genes which make up chromosones that determine charecteristics such as etc........

i gues that would count as my question

 

[Mudkip94]

iv'e seen a question like this before but ill give it a shot.

carbon dioxide and the property that makes a greenhouse gas effecvtive is that it traps heat in.

Actually, it's water vapour! You've been brainwashed by the mass media and Al Gore! CO2 is a greenhouse gas but makes up a VERY small percentage of all greenhouse gases and does VERY little to affect the climate!

Also, CO2 is VERY poor at trapping heat compared to other greenhouse gases. This is because a CO2 molecule is very symmetrical.