precision measuring. precision – how close together or repeatable the results are –a precise...
TRANSCRIPT
Precision Measuring
Precision Measuring• Precision – How close together or repeatable
the results are– A precise measuring instrument will give nearly the
same result each time that it is used.
• Accuracy – How close a measurement is to the accepted value
– For example, a balance loaded with a standard 100g weight should read 100g. If it doesn’t, then the balance is inaccurate.
Precision measuring tools are needed for accuracy
Precision Measuring
• Precision = REPROCUCIBILITY
–Checked by repeated and repeated measurements.
• Accuracy = CORRECTNESS
–Checked by using a different form of measurement and obtaining the same value
Steel Rule
Micrometer
Tools for Precision Measuring
Digital Caliper
Dial Caliper
Tools for Precision Measuring
The dial caliper is a precision measuring instrument.
The caliper’s blade is broken into inchesand tenths of an inch (graduations).
Reading a Dial Caliper
inch
Each inch is broken into ten parts, each part is 1/10 or 0.1 of an inch
{
The caliper’s dial graduations show thousandths (.001) of an inch.
The reference edge keeps track of larger increments; the dial shows us smaller increments.
Reading a Dial Caliper
One full revolution of the pointer on the dial equals one hundred thousandths (.100)(the same as 1/10 of an inch)
Blade
Inside Measuring Faces
Outside Measuring Faces
Dial
Fine Adjustment Screw
Dial Clamp Screw
Clamp Screw
Dial Caliper Parts
Step 1: Read inches from the blade
1 to 6 inches
2
Reading a Dial Caliper
Step 2: Read tenths of an inch from the blade
Reading a Dial Caliper
1 in. – 6 in.
0 to 9 tenths of an inch
2 3
Step 3: Read thousandths of an inch from the dial
Reading a Dial Caliper
0 to 9 tenths of an inch.001 to .099of an inch
2 3 2 8 1 in. – 6 in.
Dial Calipers Measure
• Thickness or Outside Diameter
Dial Calipers Measure
• Thickness or Outside Diameter
• Inside Diameter or Space Width
Dial Calipers Measure
• Thickness or Outside Diameter
• Inside Diameter or Space Width
• Depth
Dial Calipers Measure
• Thickness or Outside Diameter
• Inside Diameter or Space Width
• Depth
• Step Distance
Discussion Questions• List measurement tools…
Steel Rule Tape Measure
Dial Caliper Meter Stick
• Explain which one of the tools listed would be best to use and why when measuring: -The hallway
-Engineering Notebook
-Pencil diameter
-Height of your desk
Image Resources
Microsoft, Inc. (2008). Clip Art. Retrieved October 10, 2008, from http://office.microsoft.com/en-us/clipart/default.aspx
Wikimedia commons (2008). Retrieved October 15, 2008, from http://commons.wikimedia.org/wiki/ImageCaliper