1. St Brendan’s Sixth Form College A Level Physics
James Lawton and Christi Brasher

2. Welcome to physics
But what is it….

3. PHYSICS
THE STUDY
OF EVERYTHING

4. The range of physics The very small… To the very large…..
Question – what is the smallest think you know about?
The largest ?

5. Each QUARK in this proton
is a million million millionth of a metre in diameter!
The MILKY WAY galaxy is a thousand million million million meters in diameter!
How could we write this diameter? Get students to offer suggestions.
Physicists use standard form to make sense of these extreme numbers.

6. Standard Form 1/10 = 1x10-1 1/1000 = 1x10-3 0.0000476 = 4.76 x10-5
How could we write this diameter? Get students to offer suggestions.

7. Standard Form A million million millionth of a metre 1 x 10-18 m
A thousand million million million meters
1 x 1021 m
How could we write this diameter? Get students to offer suggestions.

8. Unit Prefixes

9. Precision and uncertainty
A number that represents a physical measurement does more than give a value of quantity. It gives an indication of the precision of the value.
A person measures a coin. Their results are :
(i) 2.4 cm using a ruler
(ii) 2.38 cm using vernier callipers
(iii) cm using a micrometer.
Issue significant figures info sheet.

10. Precision and uncertainty
(i) 2.4 cm using a ruler
(ii) 2.38 cm using vernier callipers
(iii) cm using a micrometer.
In each case the person measured the coin as accurately as they could. The results show the certainty of the measurement.
The last digit has an implied uncertainty of (+/-) 1

11. Standard form and precision
What is the volume in m3 of a cube that has sides each of 0.20mm
The number 0.20 is precise to 2 significant figures The zero is significant if it does more than just fill the space to the decimal point.
Explain zeros and sig figs

12. Standard form and precision
What is the volume in m3 of a cube that has sides each of 0.20mm
0.20mm = 0.20 x10-3m (= 2.0 x10-4m)
(0.2 x10-3)3 = 8.0 x10-12 m3
Notice how the unit changes to m3
Allow students time to try it out then talk through pointing out sig figs and how to multiply powers of ten
8 x10-3
8.0 x10-3
8.00 x10-3

13. Remember: Standard form
Your turn
What is the area in m2 of a piece of standard A4 paper?
21.0cm x 29.7cm
21.0x10-2m x 29.7x10-2m = m2
6.24x 10-2m2
Remember: Standard form
Sig figs
Units

14. Precision and uncertainty
A number that represents a physical measurement does more than give a value of quantity. It gives an indication of the precision of the value.
A person measures a coin. Their results are :
(i) 2.4 cm using a ruler
(ii) 2.38 cm using vernier callipers
What are the percentage uncertainties above?
Explain that we can quantify uncertainty as a percentage of the value of the data.

15. Absolute vs Percentage errors
2.4 = /- 0.1
(0.1/2.4) x 100 = 4.166% = 4% (1 sig fig)
2.38 = /- 0.01
(0.01/2.38) x 100 = 0.420% = 0.4% (1 sig fig)

16. (i) when multiplying and dividing the result has the same number of significant figures as the least precise piece of data.
(ii) when adding or subtracting the result has the same number of decimal places as he least precise piece of data.
(iii) express the answer to addition and subtraction questions as a value ± the sum of the individual absolute errors.
(iv) express the answer to division , multiplication, powers etc as the sum of the percentage errors for each value.
Issue

17. Calculating volume worksheet.
Your turn
Calculating volume worksheet.