SPA Skill 1 Test
- SPA Test in Term 2 week 8
- Content: Revise Practicals PR 1, 2 and 3.
- Must bring own calculator!
- The experiment done individually in 50 min
- In this experiment, you will be assessed on your ability to
- make observations and/or readings/measurements , and
- present data (record your measurements to correct d.p.)
Read and revise the learning points from practicals PR1, 2 and 3
- Post any questions you have below!
Comments (8)
Yeng Mun said
at 4:41 pm on Feb 20, 2011
Mr Ang,
For the calculated value, does it mean that for addition and subtraction, the answer should be presented in 1,2 or 3 dp according to the precision of the measurement, or does it mean that it should be in 2 or 3 sf?
If the answers for division is supposed to be in 2 or 3 sf, then why is average in 2or 3 dp when it involves division? Is it because it represents a measurement?
Thank you
johnlittlephysics said
at 3:40 pm on Aug 10, 2011
1. Calculations
a. Addition and subtraction (not commonly encountered)
To follow smaller d.p. (decimal place) of the numbers used.
e.g. 2.34 (2 d.p.) + 1.2 (1 d.p.) = 3.5 (round off to 1 d.p.)
b. Multiplication and division (most common type of calculations)
To keep final answer to only 2 or 3 s.f. (significant figures).
2. Use data from actual measurements (from instruments).
a. follow the decimal place (precision) of the instrument.
b. for the average of a few readings - follow the same d.p.
E.g. readings from ruler: 2.4 cm, 2.5 cm. 2.7 cm (1 d.p.)
The average reading = 2.53333 = 2.5 cm (round off to 1 d.p.)
Jennifer Yao said
at 11:02 pm on Feb 21, 2011
Mr Ang, I still dun quite understand the connection between d.p and s.f
johnlittlephysics said
at 3:47 pm on Aug 10, 2011
See my reply above.
Measurements from instruments are usually associated with d.p.
Calculations from values (e.g. in physics problems) are usually associated with s.f.
Examples of s.f.:
1 s.f. : 0.02, 5, 60, 8000
2 s.f. : 0.020, 5.1, 61, 8200
3 s.f. : 0.0203, 5.02, 61.0, 8020
4 s.f. : 0.02030, 5.021, 61.03, 8021
Pang Seok Mun said
at 4:14 pm on Aug 10, 2011
Mr Ang, So to be well prepared for SPA, we have to remember all the things we have learnt during the 3 practicals u mentioned above?
johnlittlephysics said
at 4:17 pm on Aug 10, 2011
That's right Seok Mun.
Be familiar with the instruments you've used: how to use correctly, how many d.p. to record the readings (precision).
Jazlynn said
at 8:12 am on May 7, 2012
Hi Mr Ang,
When reading a vernier calipers, the second step is to find the line at which both 'rulers' meet right? And what if there is no common line (meet exactly to form a straight line)?
Sorry for the terrible knowledge of terminology (i hoped its spelled correctly)
Wu Fan said
at 2:10 pm on May 7, 2012
Uh Jazlynn, the lines will meet at some point. :)
~Wu Fan
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