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What Happened To Numeracy?
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Not sure what the PM means by, pupils will study Maths until 18, I assume he means the ones that are still in education. Anyway I find it shocking that:
"Around eight million adults in England have the numeracy skills of primary school children, " - so what happened? Why are we so innumerate as a nation? I'm not talking about Calculus here just basic 'rithmetic.
Not sure what the PM means by, pupils will study Maths until 18, I assume he means the ones that are still in education. Anyway I find it shocking that:
"Around eight million adults in England have the numeracy skills of primary school children, " - so what happened? Why are we so innumerate as a nation? I'm not talking about Calculus here just basic 'rithmetic.
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10cs: "Where are you going with this, TTT? I know what a parsec is and how it is used. Not being a professional astronomer or mathematician, why do I need to know more than that? I vaguely recall that its something to do with the arc of the Earths' orbit. Or maybe not! Hey ho! " - clearly you don't know!
//Unless the definition of a parsec is known or provided, how is anyone meant to calculate the distance in light-years?//
I sort of half explained it, Corby (and no, I did not and have not looked it up). It is short for "parallax second". This is from memory, so it may not be spot on:
if you observe a body in space and draw a line to it from the earth, and then observe the same object six months later (when the Earth is on the opposite side to the Sun) and draw another line to it, you can form a triangle (with the Earth's diameter as its base). When the angle at the top of the triangle is two seconds of an arc, the distance to the object will be around 3 light years (can't recall the exact figure). The definition of parsec is when the triangle formed by the radius of the Earth's orbit subtends the angle at one second of an arc.
So you have a right-angled triangle where you know the length of the "opposite" side (the Earth's radius) and using the tangent ratio (opposite/adjacent) you can calculate the length of the adjacent side (the distance from the Earth to the object) when the angle is one second. This turns out to be a bit over three light years (about 18 million million miles). Unfortunately my "four-figure tables" do not go down to seconds of an arc, so I'll have to rely on the figure which others have calculated. But I calculate the tangent ratio (93million/18million million) to be approximately 0.000005167.
I think that's about right. But I may be wrong! :-)
I sort of half explained it, Corby (and no, I did not and have not looked it up). It is short for "parallax second". This is from memory, so it may not be spot on:
if you observe a body in space and draw a line to it from the earth, and then observe the same object six months later (when the Earth is on the opposite side to the Sun) and draw another line to it, you can form a triangle (with the Earth's diameter as its base). When the angle at the top of the triangle is two seconds of an arc, the distance to the object will be around 3 light years (can't recall the exact figure). The definition of parsec is when the triangle formed by the radius of the Earth's orbit subtends the angle at one second of an arc.
So you have a right-angled triangle where you know the length of the "opposite" side (the Earth's radius) and using the tangent ratio (opposite/adjacent) you can calculate the length of the adjacent side (the distance from the Earth to the object) when the angle is one second. This turns out to be a bit over three light years (about 18 million million miles). Unfortunately my "four-figure tables" do not go down to seconds of an arc, so I'll have to rely on the figure which others have calculated. But I calculate the tangent ratio (93million/18million million) to be approximately 0.000005167.
I think that's about right. But I may be wrong! :-)
NJ, the question asked was, "how many ligth years in a Parsec?" [sic]
From Wikipedia, "The parsec unit...is defined as the distance at which 1 au subtends an angle of one arcsecond"
Without knowing what "1 au" and "one arcsecond" are, how can someone calculate the answer?
I wonder how often, in everyday life, does the distance of a parsec have any relevance?
From Wikipedia, "The parsec unit...is defined as the distance at which 1 au subtends an angle of one arcsecond"
Without knowing what "1 au" and "one arcsecond" are, how can someone calculate the answer?
I wonder how often, in everyday life, does the distance of a parsec have any relevance?
Zebu 17.29
"For example;
Student measures the length and width of a room and finds their respective values to be 4 metres and 3 metres. Multiplying these two values (4 x 3) gives 12 square metres or 12 m²
Subsequently student purchases carpet to cover floor of room."
I think 12 square meters and 12m² are a bit different if you're ordering carpet!
"For example;
Student measures the length and width of a room and finds their respective values to be 4 metres and 3 metres. Multiplying these two values (4 x 3) gives 12 square metres or 12 m²
Subsequently student purchases carpet to cover floor of room."
I think 12 square meters and 12m² are a bit different if you're ordering carpet!
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