Measuring Height Yourself: 2 Ways to Calculate BMI

[qspeechc]

Today my sister asked me to measure her height so she can calculate her BMI. Being the lazy lout that I am I told her to measure herself. And then I started thinking of ways she could actually measure herself. I am embarassed to admit I could only think of two ways:

1) Let's round out her height to the nearest centimetre (oh yes, metric system! get with it). She should draw a line on the ground and mark of the metres. If she places copies of herself end-to-end -- by marking off her head and then placing her feet there and continuing, etc. -- eventually her head will coincide with an integer metre, allowing her to calculate her height.

2) Run into a pool and record the time her feet enter the water, and when her head passes the surface of the water. Then she measures the height of the ground from the height of the water. Of course she shouldn't jump into the pool, but simply run forward. A simple calculation will give her height.

Of course neither of these ideas is practiceable, but could work in theory. Nevertheless it's quite fun to think of ways she could measure her own height. Can you think of any other ways?

 

[Dembadon]

Today my sister asked me to measure her height so she can calculate her BMI. Being the lazy lout that I am I told her to measure herself. And then I started thinking of ways she could actually measure herself. I am embarassed to admit I could only think of two ways:

1) Let's round out her height to the nearest centimetre (oh yes, metric system! get with it). She should draw a line on the ground and mark of the metres. If she places copies of herself end-to-end -- by marking off her head and then placing her feet there and continuing, etc. -- eventually her head will coincide with an integer metre, allowing her to calculate her height.

2) Run into a pool and record the time her feet enter the water, and when her head passes the surface of the water. Then she measures the height of the ground from the height of the water. Of course she shouldn't jump into the pool, but simply run forward. A simple calculation will give her height.

Of course neither of these ideas are practiceable, but could work in theory. Nevertheless it's quite fun to think of ways she could measure her own height. Can you think of any other ways?

There is an apparatus that is used to measure the vertical leap of an athlete at a sports combine. If she could construct something that would be similar, but taller than herself, she could measure how tall she was.

http://images.whereilive.com.au/images/uploads/2009/02/23/27de08fece1970ba9dca4a502ea5a433_resized.JPG

In the photo, the athlete hits as many horizontal "pegs" as he can in order to measure how far he's traveled off of the ground. If she could do the same, except walk through hers, she'd be able to measure from the ground up to the last vertical "peg" to get an approximate height.

 

[qspeechc]

Well, yes, that would work, but my methods are certainly more fun!

 

[DanP]

1. Get a pencil and a ruler. Position yourself against the door frame. Use ruler and put it against the door frame and perpendicular against the head. Keep it there. Rotate, mark frame with pencil.

Take a measuring device and measure the height. Delete mark. Repeat 3 times and average.

Simple. Practical. Can be done by anyone. Does not involves NASA devices.

2. Stop being lazy and help her.

 

[Kronos5253]

Measure the length from fingertip to fingertip (of the middle finger) when she spreads her arms. It's the same as her height.

 

[MotoH]

1. Get a pencil and a ruler. Position yourself against the door frame. Use ruler and put it against the door frame and perpendicular against the head. Keep it there. Rotate, mark frame with pencil.

Take a measuring device and measure the height. Delete mark. Repeat 3 times and average.

Simple. Practical. Can be done by anyone. Does not involves NASA devices.

2. Stop being lazy and help her.

Thank God someone other than me thought of this.

Isn't the point of science to make things easier?

 

[Dembadon]

I don't remember qspeechc asking anyone to refrain from offering impractical solutions. Of course there are easier ways to do it, but what would science be without ingenuity, whether practical or not? Have some fun guys, sheesh.

MotoH:

I'd say that we find easier ways to do things by way of using science, but that is not its sole purpose. In science, we endeavor to understand the world around us, whether or not it leads to practical application.

 

[Borek]

Measure the length from fingertip to fingertip (of the middle finger) when she spreads her arms. It's the same as her height.

It is not. It is close, but different.

 

[Monique]

She should just take a picture of herself holding a credit card:

http://itunes.apple.com/us/app/rulerphone-camera-measuring/id288774794?mt=8

 

[tiny-tim]

sisters!

Today my sister asked me to measure her height so she can calculate her BMI. Being the lazy lout that I am I told her to measure herself.

Quite right! What has she ever done for you?

Go to the card shop and buy her a 2-metre-tall "I'm sorry i didn't help you to measure your height" card.

 

[leroyjenkens]

Measure the length from fingertip to fingertip (of the middle finger) when she spreads her arms. It's the same as her height.

That's not accurate. People's arm length and height vary proportionally from person to person. There's a fighter in the UFC who has a measure of 84.5 inches fingertip to fingertip, yet he's only 6'4".

 

[Jimmy Snyder]

Do what the physicists do, work in units where her height is 1.

-or-

Tell her to lie down on the floor with a book at her feet and a book at her head. Then get up and and measure the distance between the books.

 

[DaveC426913]

Do what the physicists do, work in units where her height is 1.

Best answer.

Tell her to lie down on the floor with a book at her feet and a book at her head. Then get up and and measure the distance between the books.

Inaccurate. She will be taller lying down than she is standing up.

 

[DaveC426913]

Have her bend over backwards and grab her ankles touching the soles of her feet to the top of her head, forming as circular a shape as possible. Then have her measure the distance from heel to small-of-back. Multiply by pi.

 

[rootX]

Standing in sun and measuring shadow and then shadow of a known object..

 

[Gokul43201]

Inaccurate. She will be taller lying down than she is standing up.

Besides, this is only good for measuring your length, not your height.

 

[Newai]

Because a ruler can teeter-totter on your head, it's better to just grab a square, like a book, and line the spine against the wall. Stand against the wall and line up the book, then mark in the corner by the spine on the wall and measure the distance up to that.

I also mark where my eyes are and other features, and at a distance I periodically examine the marks to develop a visual height gauge against my own.

 

[Gokul43201]

Because a ruler can teeter-totter on your head, it's better to just grab a square, like a book, and line the spine against the wall. Stand against the wall and line up the book, then mark in the corner by the spine on the wall and measure the distance up to that.

Just remember to use a paperback rather than a hard-cover! Unless you have a flat head. Or if you don't care about sixteenths of an inch.

 

[Jimmy Snyder]

Inaccurate. She will be taller lying down than she is standing up.

Not everyone is as fat as me.

 

[Moonbear]

Who cares if her height is accurate if she's only using it to calculate BMI? BMI is only useful on a population basis anyway and would only give a very rough approximation on an individual basis that can generally be determined just by LOOKING at the person.

It's close enough to just stand against the wall, put the pencil on the top of your head and mark the wall to measure it. Sure, you'll be off by the radius of a pencil, less than a 1/4 of an inch, so no big deal.

 

[DanP]

Who cares if her height is accurate if she's only using it to calculate BMI? BMI is only useful on a population basis anyway and would only give a very rough approximation on an individual basis that can generally be determined just by LOOKING at the person.

This is why I am advocating the mirror.

Mirror mirror on the wall who is fairest of them all ?

 

[Moonbear]

This is why I am advocating the mirror.

Mirror mirror on the wall who is fairest of them all ?

Yep. If quspeechc was a good brother, he would just look up and say, "You're fat; there, now you don't need to measure yourself." At least that's what I would have told my sister if she ever asked me something like that (and she's always been skinny as a rail). If I was in a more charitable mood, I might have told her something more like, "You'll never have boobs if you stay so skinny. Go away!"

 

[cronxeh]

Yep. If quspeechc was a good brother, he would just look up and say, "You're fat; there, now you don't need to measure yourself." At least that's what I would have told my sister if she ever asked me something like that (and she's always been skinny as a rail). If I was in a more charitable mood, I might have told her something more like, "You'll never have boobs if you stay so skinny. Go away!"

MOONIEEE

*swings off a ceiling fan*

hey hey

 

[DanP]

If I was in a more charitable mood, I might have told her something more like, "You'll never have boobs if you stay so skinny. Go away!"

Never say never. Cosmetic surgery works wonders.

 

[magpies]

Have her go to a fair and stand next to one of the if your not this tall signs.

 

[DaveC426913]

Who cares if her height is accurate if she's only using it to calculate BMI? BMI is only useful on a population basis anyway and would only give a very rough approximation on an individual basis that can generally be determined just by LOOKING at the person.

It's close enough to just stand against the wall, put the pencil on the top of your head and mark the wall to measure it. Sure, you'll be off by the radius of a pencil, less than a 1/4 of an inch, so no big deal.

We were obliging the OP:

Nevertheless it's quite fun to think of ways she could measure her own height. Can you think of any other ways?

 

[rootX]

Yep. If quspeechc was a good brother

good sister

However, only a male would exhibit the characteristics described in the OP

 

[Integral]

Who cares if her height is accurate if she's only using it to calculate BMI? BMI is only useful on a population basis anyway and would only give a very rough approximation on an individual basis that can generally be determined just by LOOKING at the person.

It's close enough to just stand against the wall, put the pencil on the top of your head and mark the wall to measure it. Sure, you'll be off by the radius of a pencil, less than a 1/4 of an inch, so no big deal.

This only works for normal people. If you are not normal then there will be signifigant error.

 

[zoobyshoe]

Measure the length from fingertip to fingertip (of the middle finger) when she spreads her arms. It's the same as her height.

Strangely, no. With just a very small sampling of people (4) I once discovered that none of their wingspans exactly matched their height. Two of the four, in fact, had a wingspan greater than their height! One by an inch and the other by three inches (a real monkey man)! All done in stocking feet.

 

[GeorginaS]

Besides, this is only good for measuring your length, not your height.

Okay. Funny!

 

[GeorginaS]

Strangely, no. With just a very small sampling of people (4) I once discovered that none of their wingspans exactly matched their height. Two of the four, in fact, had a wingspan greater than their height! One by an inch and the other by three inches (a real monkey man)! All done in stocking feet.

Well see? There was the problem right there. You had a guy who was wearing stockings.

 

[qspeechc]

Yes I should have been clearer. I want to see how many ways we can come up with for measuring your own height. I have found three more.

Drop an object from the height of the top of your head and time how long it takes to reach the ground. Simple physics will give you your height.

Construct a pendulum, say from some string and a fishing weight, of length equal to your height. Then you can find the period of this pendulum for small oscillations, over several oscillations then taking the average, and thus you can find the length of the pendulum.

Stand a certain distance from a mirror, say 3 metres. Place a laser at the top of your head and reflect the beam of the mirror so that the beam touches the tip of your feet. Then measure the angle the laser makes with the vertical or horizontal and simple trig gives you your height.

Have her bend over backwards and grab her ankles touching the soles of her feet to the top of her head, forming as circular a shape as possible. Then have her measure the distance from heel to small-of-back. Multiply by pi.

 

[Kronos5253]

Strangely, no. With just a very small sampling of people (4) I once discovered that none of their wingspans exactly matched their height. Two of the four, in fact, had a wingspan greater than their height! One by an inch and the other by three inches (a real monkey man)! All done in stocking feet.

Haha yeah I know, but it doesn't have to be 100% accurate, it just has to be a relatively good way to measure your height by yourself.

 

[BobG]

If I was in a more charitable mood, I might have told her something more like, "You'll never have boobs if you stay so skinny. Go away!"

Surprisingly true. Unwanted fat can be used as 'natural' breast implants: Two-in-one op joy for women

 

[tiny-tim]

Stand in front of at least a half-length mirror, mark the position of your head and your heels with lipstick, measure the distance between them, and double it.

 

[cronxeh]

When Shawn Johnson gained weight, I was glad that we had an 18 year old athlete who will actually have boobs and a great body once she loses that baby phat

Can't wait for the Sports Illustrated, FHM, and Playboy coverage on Shawny

 

[MotoH]

When Shawn Johnson gained weight, I was glad that we had an 18 year old athlete who will actually have boobs and a great body once she loses that baby phat

Can't wait for the Sports Illustrated, FHM, and Playboy coverage on Shawny

 

[CRGreathouse]

It is not. It is close, but different.

Ooh, I wonder if there's any data about this online. Do you think there's a correlation between height and (height - armspan)? Positive or negative? And what are good figutes for the mean and standard deviation for (height - armspan)?

 

[Borek]

Ooh, I wonder if there's any data about this online. Do you think there's a correlation between height and (height - armspan)? Positive or negative? And what are good figutes for the mean and standard deviation for (height - armspan)?

Interesting question, but no idea.

Sounds like good activity for a class - I remember reading abour measuring beans as an element of introducing Gaussian distribution. Finding correlation could be a nice complement.

 

[magpies]

She could walk her shoes up her self one after the other.

 

[Borek]

If she knows how to snap with her toes, she can measure time between the snap felt and snap heard, difference times 330 m/s gives the distance.

To be precise she should also hit something with a top of her head and measure time between hit and sound as well, then just sum both distances.

 

[Kronos5253]

If she knows how to snap with her toes, she can measure time between the snap felt and snap heard, difference times 330 m/s gives the distance.

To be precise she should also hit something with a top of her head and measure time between hit and sound as well, then just sum both distances.

Good luck with that one haha