# Oranges and Earths

Discussion in 'CycleChat Cafe' started by cisamcgu, 9 Apr 2008.

1. ### cisamcguGuru

Location:
Merseyside-ish
The circumference of the Earth is 40,008 km. So if a piece of string was wrapped around the equator (asuming the Earth is a perfect sphere), then the string would also be 40,008 km long. Now, imagine cutting this string and adding 1 metre to it's length, so the string is now 40,008 km + 1 metre. If the string was now lifted from the Eath's surface all the way round, how much would it be raised from the surface ?

Now, take an orange, with a circumference of say, 15cm. Wrap a piece of string around it, then cut it and add a metre. How much would the string be lifted from the surface of the orange ?

Answers on a postcard to ......

Andrew

2. ### ArchMarried to Night Train

Location:
Salford, UK
Ah, I think I've heard this before. Is it the same for both and something like an inch (or a cm)?

(not that I can be bothered to work it out and check...)

3. ### ArchMarried to Night Train

Location:
Salford, UK
no, hang on, that can't be right...

4. ### MelvilStandard nerd

4 miles for both and I claim.............................absolutely nothing whatsoever.

5. ### DanBatNew Member

Location:
Hackney
the same distance in each case (100 / 2Pi centimeters).

Or if I am wrong maybe that explains why I dont have room for mudguards when i fit fatter tyres.

6. OP

### cisamcguGuru

Location:
Merseyside-ish
It is the same for both, and it is, I think, about 16cm .. Which I find astounding... 40,000KM .. add a metre and it raises by 16cm !!!

7. ### TheDoctorMan-MachineModerator

Location:
Stevenage
It's about 6 inches . Use the formula for circumference of a circle
Circumferance = diameter times pi

If the circumference increases by a metre, or 39 inches, the diameter goes up by (39/3.14) inches or just over 12 inches, so the radius goes up by half of that.

Checking on a calculator...16 cm is right.

8. ### abchandlerSenior Member

Location:
Worcs, UK
[pedant] Why would you need to cut it? Surely a piece of string wrapped around a circle would have two cut ends anyway? Or is this special torus string that we're using?[/pedant]

Location:
Somerset

i don't care

11. ### ArchMarried to Night Train

Location:
Salford, UK
So I was almost right...

Ok, so how many chain stitches do I need to cast on in DK yarn on a 4mm crochet hook, to crochet a hat for the earth?

Tell me that, clever clogses....

'coz I haven't got a clue...

Location:
NE England
1 metre

13. ### LandslideRare Migrant

Location:
Called to the bar
OK…

Assuming you start at the brim, and want the brim to reach the equator…

40,008km = 40,008,000m
1m = 39.3700787"
40,008,000m x 39.3700787 = 1,575,118,108.62"

http://www.freepatterns.com/pages/tips/yarn_faq.html reckons 16 sts = 4" (therefore 4 sts = 1"), but recommends a size 5/6 hook for DK yarn.
So (assuming you're happy to move up a hook size)…

1,575,118,108.62" x 4 sts = cast on 6,300,472,434 sts.

Given the hat will have a bit of stretch, I'd say you'll be safe with 6.3 billion stitches. Should keep you out of mischief for a while!

14. ### abchandlerSenior Member

Location:
Worcs, UK
Or, start at a pole, and you only need one

15. ### ArchMarried to Night Train

Location:
Salford, UK

Thank you so much. I happen to have my crochet with me today, to do some at lunch. I will start now.

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11... Talk among yourselves, this may take some time...