How to calculate magnification of a leaf

Hi im doing Biology AS with the OCR board. The topic on how to calculate magnification and what units to use, and all the relevant calculations really catch me out. Can anyone take me step by step how to do this, with an example. Any help would be much appreciated. A rep will also be given

You should be provided with a scale in any scaled down diagram. Hopefully it'll give a line and then the length it represents, for example a milimetre.

Measure that line with a ruler. Say it measured 1cm, which equals 10mm. Measured Size/Actual Size will give you your magnification. In this case, 10x.

Thanks for that. What about if it says calculate the actual size? what are all the unit conversions? e.g 1cm = 10mm, is there any others i need to know?

If you wish to calculate the actual size you just rearrange the equation above. Measured Size/Maginification = Actual Size There is nothing wrong with keeping the same units as that of the measured size (unless the questions states otherwise). For example, if you measured something to be 1cm, and the magnification was 1000, the actual size can be expressed as 1/1000cm or 0.001cm.

This can in turn be converted to mm, um or nm.

Lets just say magnification = m actual size = a picture size = X

To find the magnification you'd use X/a.

ok - first thing don't panic! i didn't understand it until like a week ago - and that was because i had mentally given up on it therefore i wasn't stressing about it. so..

magnification is the number of times an image is compared with its real size

http://www.cellsalive.com/howbig.htm

ok well i hope that helps - just let me know if u still don't understand!!

(Original post by sheena18) 1mm (millimetre) = 10^-3m 1 (micrometre - sorry i can't type it - its a funny 'u' then a 'm') = 10^-6m 1nm (nanometre) = 10^-9m

1A (angstrom) = 10^-10 m

The micro sign is generally done using the Alt Gr key plus M, giving you a µ

The "to the power of" elevation in the text is done using the [sup] tags. Most people can never be bothered though since it's really time consuming to do it. Alternatively for writing things down here is done using the [sub] tags.

Interesting forum information for science/math forums.

(Original post by Iscariot)
The micro sign is generally done using the Alt Gr key plus M, giving you a µ

Edit: All you have to do to work out magnification is divide the big number by the small one... I have no idea why some people think this is complicated!

(Original post by Iscariot)
1 millimetre (mm) = 10-3m
1 micrometer (µm) = 10-6m
1 nanometre (nm) = 10-9m
1 angstrom (A) = 10-10m

The micro sign is generally done using the Alt Gr key plus M, giving you a µ

The "to the power of" elevation in the text is done using the [sup] tags. Most people can never be bothered though since it's really time consuming to do it. Alternatively for writing things down here is done using the [sub] tags.

Interesting forum information for science/math forums.

I can't find the Gr key!? where is it??

(Original post by Abra)
I can't find the Gr key!? where is it??

Sheena: you are a legend! And thanks to all the other people, i understnd it properly now!

Quick question! In my test paper it gives us the actual size of 1.5µm. so how do i convert that to nm?

(Original post by Silent Assassin)
Quick question! In my test paper it gives us the actual size of 1.5µm. so how do i convert that to nm?

Ok here is a few examples i need help on: 1) The line AB in fig 3:1 represents an actual distance of 1.5µm. calculate the magnification of the drawing. ( so in the diagram AB measures 1.2cm) 2) the actual thickness of the leaf along the line EF is 0.6mm. calculate the magnification of the diagram (the length of EF when i measured = 1.3cm) 3) the actual diameter of the nucleus, measured along the line XY is, 7µm. calculate the magnification of the nucleas (the length of XY = 4.4cm)

Now.... all the times, when i measured the lengths, they seemed pretty unusual measurments. I didn't understand. Like 4.4cm, 1.2cm..... etc. Can anyone please go through the answers with me, its so annoying i've been stuck with this flippin thing for 4 hours!!!!!!!!!!!!!!

Remember cm = 10^-2m, µm = 10^-6m, mm = 10^-3m

(Original post by Silent Assassin) 1) The line AB in fig 3:1 represents an actual distance of 1.5µm. calculate the magnification of the drawing.

( so in the diagram AB measures 1.2cm)

2) the actual thickness of the leaf along the line EF is 0.6mm. calculate the magnification of the diagram

(the length of EF when i measured = 1.3cm)

3) the actual diameter of the nucleus, measured along the line XY is, 7µm. calculate the magnification of the nucleas

(the length of XY = 4.4cm)

Thanks very much, but the mark scheme gives some strange answers: for the 2nd and 2rd examples:

2) award two marks if correct answer (50) is given if measurement incorrect but in the range 25 –35 mm, allow one mark for a correct calculation 30/0.6 / 3(cm)/0.6(mm) / 3(cm)/0.06(cm) ; A +/- 1mm

50 ; A 48 - 52 R if units given

3) 7 cm / 70 mm or measurement / 7 m ; A 71 mm / 70 000 m
(magnification = x ) 10 000 ; A 10 143 NOT units (e.g. mm)

The parts highlighted in bold, are exactly from the mark schemes.

im riduclously confused with all the figures

if possible could you put the figures from standard form into normal figures. Im not particularly good at maths, so i dont understand figures very well

(Original post by Silent Assassin)
im riduclously confused with all the figures