Celisus vs Farenheit

[Besoeker]

Forgive me if this has been posted already. I started reading through this and got bored to tears. But the way I convert C to F is take the degrees in C and multiply by 1.8 then add 32 and you get F.

Leaving aside the obvious question of why would you want to.....
For mental arithmetic 9/5 is probably easier than 1.8.

 

[tallgirl]

Leaving aside the obvious question of why would you want to.....
For mental arithmetic 9/5 is probably easier than 1.8.

Multiplying by 1.8 isn't that hard -- it's sometimes easier than multiplying by 9 and dividing by 5.

What's 37 x 1.8? Simple 37 x 2 - 3.7 x 2, 74 - 7.4. 74 - 7.4 = 66.6. Add in the 32 and you've got 98.6F.

What's 37 x 9 / 5? 63 + 270 = 333. 333 / 5 = 666 / 10 = 66.6. Add in the 32 and you've got 98.6F again.

If you don't know the multiplication and division tricks ("times 5 is the same as times 10 divided by 2" and so on) it's all a pain to do in your head.

 

[ggunn]

Multiplying by 1.8 isn't that hard -- it's sometimes easier than multiplying by 9 and dividing by 5.

What's 37 x 1.8? Simple 37 x 2 - 3.7 x 2, 74 - 7.4. 74 - 7.4 = 66.6. Add in the 32 and you've got 98.6F.

What's 37 x 9 / 5? 63 + 270 = 333. 333 / 5 = 666 / 10 = 66.6. Add in the 32 and you've got 98.6F again.

If you don't know the multiplication and division tricks ("times 5 is the same as times 10 divided by 2" and so on) it's all a pain to do in your head.

If God would have wanted us to do math in our heads He wouldn't have given us calculators, preferably HP ones operating in RPN.

 

[pfalcon]

If God would have wanted us to do math in our heads He wouldn't have given us calculators, preferably HP ones operating in RPN.

Who uses HPs Really Pathetic Notation anymore instead of TIs Almost Omniscient Stuff?
If you're desperate to safe one or two keystrokes, just learn to use the ) and = better.

 

[ggunn]

Who uses HPs Really Pathetic Notation anymore instead of TIs Almost Omniscient Stuff?
If you're desperate to safe one or two keystrokes, just learn to use the ) and = better.

If you ever had to multiply, divide, add, and subtract complex numbers in the same equation (I had a sadistic Circuits prof), you would come to worship at the RPN altar. We don't need no steenking equals key!

 

[tkb]

32?F feels warmer than 0?C to me. :happyyes:

We have been using liters for many years.
Just look at any drink bottle.

 

[Besoeker]

Multiplying by 1.8 isn't that hard -- it's sometimes easier than multiplying by 9 and dividing by 5.

What's 37 x 1.8? Simple 37 x 2 - 3.7 x 2, 74 - 7.4. 74 - 7.4 = 66.6. Add in the 32 and you've got 98.6F.

What's 37 x 9 / 5? 63 + 270 = 333. 333 / 5 = 666 / 10 = 66.6. Add in the 32 and you've got 98.6F again.

If you don't know the multiplication and division tricks ("times 5 is the same as times 10 divided by 2" and so on) it's all a pain to do in your head.

True. But there are certain easy temperatures to do. Take nice warm day at 25C.
15/5 = 5
5*9 = 45
45+32 = 77F

You can do the same for 30C and get 86F. (Or you could just add 9F to 77F.)
Anyway, I remember the easy temperatures without the need for a calculation and it's fairly easy to do a simple bit of mental arithmetic to get intermediate values.

I did comment in an earlier post:

Leaving aside the obvious question of why would you want to.....

So why do I bother? I'm a Brit and I have little need for it in my professional life.

But there is a very much more important reason. My sweet wife is a southern belle. She likes deg F for the weather. If the forecast is for a pleasant 21C day I can tell her immediately that it's 70F within the degree of resolution (no pun intended) appropriate for daytime temperature.

 

[jim dungar]

For close enough.
[(?C x 2) - 10%]+32 = ?F

40?C x 2 = 80, 80-10% = 72, 72+32 = 104?F

[(?F-32) + 10%] /2 = ?C

78?F-32 = 46, 46+10% = 50/2 = 25?C

 

[Little Bill]

Leaving aside the obvious question of why would you want to.....
For mental arithmetic 9/5 is probably easier than 1.8.

Not for me, not much mental arithmetic going on with me anymore.

Multiplying by 1.8 isn't that hard -- it's sometimes easier than multiplying by 9 and dividing by 5.

What's 37 x 1.8? Simple 37 x 2 - 3.7 x 2, 74 - 7.4. 74 - 7.4 = 66.6. Add in the 32 and you've got 98.6F.

What's 37 x 9 / 5? 63 + 270 = 333. 333 / 5 = 666 / 10 = 66.6. Add in the 32 and you've got 98.6F again.

If you don't know the multiplication and division tricks ("times 5 is the same as times 10 divided by 2" and so on) it's all a pain to do in your head.

Thank you!

If God would have wanted us to do math in our heads He wouldn't have given us calculators, preferably HP ones operating in RPN.

And you!

 

[renosteinke]

Miss February sounds more voluptuous in metric My car gets more miles to the 'Imperial' gallon.

Some intellectual types like the world to be neat and orderly, hence this love for things metric. FOrget the fact that the world is a messy place; after all, hot dogs come in 10-packs while buns come in 8's. Go figure.

I was in Britain not too long ago. Half a centure after everything went 'pure metric,' EVERY schoolboy knows exactly what a yard, mile, pound, and shilling is. I pronounce 'going metric' as a failed social experiment.

 

[weressl]

I grew up with metric.
Both metric and imperial (fractional) are just as easy once you learn them.
True, imperial takes a little longer to sink in, but once it sink in that is half of half of half it can be easier than metric for some things.
Do you have problems with the 12/60/60 set up of clocks? I'm sure you don't.

The SI system is rooted in science, whereas the imperial originates at places more ancinet than that at in cases it relates to humans.

100F supposed to be the approximate normal temperature of a human body.
1 foot is the approximate length of the feet of a grown man and divided by 12, like the months of the year or one half day it results in an inch, which is the approximate width of a grown man's thumb.
1 yard is the approximate length of a grown man's stride and by striding did they used to measure land, or yard.
Normal heart-rate is about 60 beats per minute. So muliply it by itself and you get an hour. The division of the day by two times 12 has more to do with astrology and the movement of the earth, but it is nice to know that it is connected to humanity.
A pound is the weight of 7000 grains. The measurement of 'grains' is the average weight of a common - not genetically manipulated:lol: - wheat grain.

...and so on and so forth.

 

[Besoeker]

A pound is the weight of 7000 grains. The measurement of 'grains' is the average weight of a common - not genetically manipulated:lol: - wheat grain.

But why 7,000? Why not 10,000 or any other nice round number?