The InchThe Inch and How it is Built and How it is Built

3.05 BTS3.05 BTS

Skill, Skill, Precision Precision andandReading the Reading the English English StandardStandard scale to a scale to a sixteenth of an inch.sixteenth of an inch.

The InchThe Inch is the standard small unit is the standard small unit in the English Standard in the English Standard

measuring system.measuring system.

The inch is thought The inch is thought out in an common out in an common sense way that sense way that makes it easy to makes it easy to understand and understand and use…use…

if you take a bit of time if you take a bit of time to learn about its parts.to learn about its parts.

The InchThe Inch uses only a few uses only a few fractions.fractions.

1/3, 1/5, 1/6, 1/7, 1/9…1/3, 1/5, 1/6, 1/7, 1/9…

Some of the Some of the fractions fractions NEVER NEVER appearing in the appearing in the

inch are:inch are:

apply it here!apply it here!

You probably know a lot You probably know a lot about measuring already.about measuring already.

Mastering this Mastering this measurement skill measurement skill is not as hard as is not as hard as you might think.you might think.

The names of the fraction The names of the fraction numbers are:numbers are:

NumeratorNumerator

Lets make sure you remember Lets make sure you remember some important fraction terms:some important fraction terms:

DenominatorDenominator

This number is always an This number is always an odd number. If it is an even odd number. If it is an even number, REDUCE the number, REDUCE the fraction.fraction.

Numerator:Numerator: What is the What is the NUMBER of the inch parts NUMBER of the inch parts we are talking about?we are talking about?

Denominator:Denominator: This DENOTES This DENOTES the total number of parts in the total number of parts in the fractional division.the fractional division.

The only denominator The only denominator numbers are:numbers are:

1, 2, 4, 8 and 16!1, 2, 4, 8 and 16!

And now the star of our show:And now the star of our show:

The English StandardThe English Standard

Inch.Inch.And how the inch And how the inch unit is divided! unit is divided!

The blue drawing represents a small part of an English Standard

ruler graduated in inches.

We are looking at the ruler around the 27and 28 inch marks.

we need more precision!

Whole inches are good for measuring many large things…

but for most uses:

Where is the common sense place to put a dividing line?

To get a higher degree of accuracy, we need to divide the whole inches

into smaller parts.

Precisely in the middle of the

inch space!

We need a fraction to indicate the middle division. Think of the line we have just drawn as 1 of the 2 divisions.

This divides the space into two equal parts.

One Division

One Division

What is the name of this fraction line?

1/2

1/21/2

One half: one of the two divisions!

1/2

Empty measurement spaces are divided into two equal parts.

This is the common sense way inches are divided up to get more precision.

If both of the two division spaces are divided into two equal spaces, what will the total number of inch divisions be now? 4!4!

1/2

Where are the measurements located on the scale?

The names of the fraction lines are:

The two fractions represent: 1 of the 4 divisions and 3 of the 4 divisions.

1/4 3/4and

The 2 of the 4 divisions line (2/4) is reduced!

More precise measurement is still needed.

How many total inch divisions are there now?

1/4 3/4

Empty measurement spaces are still being divided into two equal parts.

8

What are the fraction names of the new lines?

Have you noticed how all the fractions do not have even numbers for their numerators?

They are all 8ths…..

Yes! (maybe)

1/8 3/8 5/8 7/8

Measurement fractions with even numerators must be reduced!

We have arrived at the final division of spaces.

We better get out our high powered TECH GOGGLES to see them!

If we divide the 8ths into two… how many total divisions will we have?

16(whew!)

1/8 3/8 5/8 7/8

1/8 3/8 5/8 7/8

There are only 8- 16th measurements!

We better get out our high powered TECH GOGGLES to see them!

If we divide the 8ths into two… how many total divisions will we have? 16(whew!)

1/8 3/8 5/8 7/8

1/8 3/8 5/8 7/8

Here are the 16th lines

That isn’t so bad, once you understand it!

We better get out our high powered TECH GOGGLES to see them!

If we divide the 8ths into two… how many total divisions will we have? 16(whew!)

1/8 3/8 5/8 7/8

1/8 3/8 5/8 7/8

Here are the 16th Fractions:

1/16 3/16 5/16 7/16 9/16 11/16 13/16 15/16

Lets look at a different English Standard ruler.

2 7 2 8

We are still looking at the 27 and 28 inches (“) area of the ruler.

It is read just like the one we have just

learned about.

The inch divided into sixteenths is one the standards of precision for the entire construction industry.

2 7 2 8

If you can measure sixteenths, you can build almost anything!

Can you identify the indicated measurements?

2 7 2 8

Method 1: Remember (memorize) what the lines indicate and identify the measurement.

2 7 2 8

It is not difficult to memorize ALL 16 measurements if you try.

Here are the 16- inch measurement fractions:

2 7 2 81/2

As you use this skill, you will memorize the measurements without trying!

¼ ¾

1/8 3/8 5/8 7/8

1/16 3/16 5/16 7/16 9/16 11/16 13/16 15/16

Method 2: Count the number of lines from the whole line and make a fraction.

2 7 2 8

9/16 of an inch (9/16”), 9 of the 16.

1 2 3 4 5 6 7 8 9

This measurement is 27- 9/16” (inches)

Here’s another: Count the number of lines, if the numerator is even, you must reduce the fraction!

2 7 2 8

10/16”, reduced to 5/8”.

1 2 3 4 5 6 7 8 9 10

This measurement is 27- 5/8” (inches)

The skill continues:

2 7 2 8

Do you reduce?

1 2 3 4 5 6 7 8

Count the number of lines…Make a fraction with the count number as numerator…. 16 is the denominator…

What is the answer?

Did you get 27-½”?

2 7 2 8

1 2 3 4 5 6 7 8

If you have started to memorize the lines, you knew this answer without all the counting work!

You are getting HOT now….

2 7 2 8

Do you reduce?

1 2 3 4 5 6 7 8 9 10 111213 14 15

Count again!Make a fraction with the count number as numerator….

What is the answer?

How about 27-15/16”?

Here is the last practice try:

2 7 2 8

Do you know it?

Look at the indicated measurement.I’m not going to number this one for you!

What is the answer?

How about 27-7/16”?

2 7 2 8

Reading measurements 100% of the time…

is an important skill to master.

There just 16 fractions used in this level of inch precision measurement.

Review:

It is an important skill to be able to accurately measure 100% of the time.

Technology depends on precise measurement to be able to do its many jobs.

2 7 2 8

Have youyou earned a new skill?

How will you use it?