Picture of the 2 lines on a platinum iridium bar

In summary, the standard meter is the distance between two scratches on a platinum iridium bar, which can only be seen with a lens. These scratches are used for making or calibrating sub standards, and there is a better picture and technical details available on the NIST website.
  • #1
fizagic
1
0
Hello all,

The standard meter was said to be the distance between two scratches on a platinum iridium bar.

http://en.wikipedia.org/wiki/Metre

Where are these scratches? I only see the bar.
 
Physics news on Phys.org
  • #2
There doesn't appear to be a good picture on wikipedia. Perhaps some google searching would turn up something else?
 
  • #3
I must say, I never thought of that before but those scratches will need to be VERY FINE for the standard length to be precise. You can probably only see them with a lens.
When they are used for making or calibrating a sub standard, they 'know' pretty well where to look for these tiny scratches because they already have a 'crude' 1m measure. They can't 'lose them'.
 
  • #5


Hello, thank you for your question. The scratches on the platinum iridium bar that were used to define the standard meter are no longer visible due to wear and tear over time. The bar has been replaced with a more accurate and stable definition of the meter based on the speed of light. However, the original platinum iridium bar is still used as a historical artifact and serves as a reminder of the evolution and refinement of scientific measurements.
 

FAQ: Picture of the 2 lines on a platinum iridium bar

What is a picture of the 2 lines on a platinum iridium bar?

A picture of the 2 lines on a platinum iridium bar is a visual representation of the two lines that are etched onto the surface of the bar. These lines are used as a standard for the international unit of length, the meter.

What are the 2 lines on a platinum iridium bar used for?

The 2 lines on a platinum iridium bar are used as a standard for the meter, which is the international unit of length. This bar is also known as the International Prototype Kilogram (IPK) and is the basis for the kilogram, the international unit of mass.

How accurate are the 2 lines on a platinum iridium bar?

The 2 lines on a platinum iridium bar are extremely accurate, with a margin of error of only 0.00005 millimeters. This level of precision is necessary for creating a standard unit of length and mass.

Why is a platinum iridium bar used for the standard unit of length and mass?

Platinum iridium is a dense, strong, and corrosion-resistant metal that is also very stable. These properties make it an ideal material for creating a standard unit of length and mass that will not change over time due to environmental factors.

How is the length of the 2 lines on a platinum iridium bar determined?

The length of the 2 lines on a platinum iridium bar was originally determined by taking the average of two measurements made by each of the two different groups responsible for creating the bar. Today, the length is determined using advanced technology and precise measurements to ensure accuracy and consistency.

Similar threads

Replies
10
Views
974
Replies
9
Views
20K
Replies
1
Views
975
Replies
3
Views
29K
Replies
7
Views
3K
Back
Top