My Math Forum  

Go Back   My Math Forum > High School Math Forum > Geometry

Geometry Geometry Math Forum


Reply
 
LinkBack Thread Tools Display Modes
May 15th, 2017, 11:20 AM   #1
Newbie
 
Joined: Oct 2016
From: United States of America

Posts: 7
Thanks: 0

Lightbulb Indirect Measurement Methods

What are a few unique ways to use indirect measurement in real life?

Example: Using a mirror on the ground and using the shadow of an object.

Thank you in advance!
Imnomermaid112 is offline  
 
May 15th, 2017, 11:33 AM   #2
Senior Member
 
Joined: Aug 2012

Posts: 1,369
Thanks: 321

Can you define direct versus indirect? For example if I use a Galilean telescope (straight through optics) is that direct? And a Newtonian telescope (uses a mirror) is indirect? Is it the use of a mirror that makes a measurement indirect?
Maschke is offline  
May 15th, 2017, 11:53 AM   #3
Senior Member
 
romsek's Avatar
 
Joined: Sep 2015
From: CA

Posts: 1,237
Thanks: 637

If using a mirror constitutes an indirect measurement, then all reflector style telescopes make indirect measurements.

Interferometers make time or distance measurements by zeroing out interference patterns in interacting laser beams. This probably fits your definition of indirect.

Liquid thermometers measure temperature by reporting the calibrated change of the volume of a liquid due to temperature. That's probably indirect.

Last edited by skipjack; May 15th, 2017 at 12:26 PM.
romsek is offline  
May 15th, 2017, 02:17 PM   #4
Senior Member
 
Joined: Jun 2015
From: England

Posts: 566
Thanks: 147

Using one of these
Attached Images
File Type: jpg profilegauge.jpg (8.6 KB, 2 views)
studiot is offline  
May 15th, 2017, 03:18 PM   #5
Newbie
 
Joined: Oct 2016
From: United States of America

Posts: 7
Thanks: 0

Indirect: Not coming into contact with the object. For example, if you were to measure the distance from the pole a to pole b, you would have to do so without touching it in any way shape of form.

Direct: Measuring with contact. For example, if you were to take a measuring tape and measure the distance from the pole a to pole b and come into contact with both of the objects, this would be direct contact.
Imnomermaid112 is offline  
May 15th, 2017, 04:49 PM   #6
Senior Member
 
Joined: Aug 2012

Posts: 1,369
Thanks: 321

Quote:
Originally Posted by Imnomermaid112 View Post
Indirect: Not coming into contact with the object. For example, if you were to measure the distance from the pole a to pole b, you would have to do so without touching it in any way shape of form.

Direct: Measuring with contact. For example, if you were to take a measuring tape and measure the distance from the pole a to pole b and come into contact with both of the objects, this would be direct contact.
Question to help me understand your definition.

When I look at a light source, the photons hit my retina, an electrical signal goes up the optic nerve to my brain, and I have a subjective experience of brightness. [Whoever figures out how the subjective experience happens wins every prize there is].

My eye/brain system isn't very quantitative. It's not even very reliable. To measure the intensity of the light I have to intercept the photon stream with a photoelectric cell, and read off the current generated by the photons, which is proportional to the number of photons per unit of time.

Is that direct or indirect?

If I bounce the photons off a mirror first does that make it indirect? What is the deal with mirrors?
Maschke is offline  
May 15th, 2017, 05:08 PM   #7
Senior Member
 
Joined: Feb 2016
From: Australia

Posts: 1,161
Thanks: 381

Math Focus: Yet to find out.
Hall effect sensors come to mind for the 'indirect' case.
Joppy is online now  
May 15th, 2017, 06:12 PM   #8
Math Team
 
Joined: Oct 2011
From: Ottawa Ontario, Canada

Posts: 9,390
Thanks: 638

Train an ant to walk at speed x.
Have the ant walk from pole to pole.
Get a timewatch.
You know what I mean....
Denis is offline  
Reply

  My Math Forum > High School Math Forum > Geometry

Tags
indirect, measurement, methods



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
How to use Indirect Kalman Filter output wkdxoghdi Algebra 0 February 15th, 2017 06:34 AM
Level of Measurement ehe3d Probability and Statistics 1 October 14th, 2015 06:55 PM
Lesson on direct and indirect proportion mikeinitaly Elementary Math 1 November 24th, 2014 06:34 AM
Indirect Proof? simon naw Number Theory 2 December 30th, 2012 07:40 PM
Polytope dimension - prove by indirect method drhachmann Algebra 0 December 1st, 2012 12:37 PM





Copyright © 2017 My Math Forum. All rights reserved.