precision measuring 1.1.3a
DESCRIPTION
Precision Measuring 1.1.3A. 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 - PowerPoint PPT PresentationTRANSCRIPT
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 100 g
weight should read 100 g. If it doesn’t, then the balance is inaccurate.
Precision measuring tools are needed for accuracy
Precision Measuring
Precision measuring tools are needed for accuracy
http://phet.colorado.edu/en/simulation/projectile-motion
Try launching a piano with an angle of 2, 80, and 85 degrees (change initial speed to 28)
The dial caliper is a precision measuring instrument.
The caliper’s blade graduations arein inches and tenths (.1) of an inch.
Reading a Dial Caliper
inch
Each inch is broken into ten, for .1 of an inch.
{
The caliper’s dial graduations are
in thousandths (.001) of an inch.
The reference edge keeps track of larger increments; the dial is for smaller increments.
Reading a Dial Caliper
Blade
Inside Measuring Faces
Outside Measuring Faces
Dial
Fine Adjustment Screw
Dial Clamp Screw
Clamp Screw
Dial Caliper Parts
Step 2 Read tenths of an inch from the blade
Reading a Dial Caliper
1 in. – 6 in. .0 in. -.9 in.
2 3
Step 3 Read thousandths of an inch from the dial
Reading a Dial Caliper
1 in. – 6 in. .0 in.- .9 in. .001 in.- .099 in.
2 3 2 8
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