IB Physics

Folders, text books, calculators, data booklet.

Assessment Paper 1 (Multiple Choice) 20% Paper 2 (Extended response- some choice) 32% SL, 36% HL Paper 3 (Options) 24% SL 20% HL Coursework SL-40 hours HL-60 hours 24%

Assessment Paper 1 (Multiple Choice) 45mins SL 1 hr HL Paper 2 (Extended response- some choice) 1¼ hr SL, 2¼ hr HL Paper 3 (Options) 1 hr SL 1¼ HL Coursework SL-40 hours HL-60 hours

Structure of course Year 12 – ALL standard level units (1 to 8) Year 13 – Options and HL units (9 – 14)

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Topic 1 – Physics and Physical measurement Use the syllabus particularly when studying for examinations The DEFINITIONS you will have to learn ‘by heart’.

Ranges of sizes, masses and times

Order of magnitude We can express small and large numbers using exponential notation The number of atoms in 12g of carbon is approximately 600000000000000000000000 This can be written as 6 x 1023

Order of magnitude We can say to the nearest order of magnitude (nearest power of 10) that the number of atoms in 12g of carbon is 1024 (6 x 1023 is 1 x 1024 to one significant figure)

Small numbers Similarly the length of a virus is 2.3 x 10-8 m. We can say to the nearest order of magnitude the length of a virus is 10-8 m.

Ranges of sizes, masses and times You need to have an idea of the ranges of sizes, masses and times that occur in the universe.

Size Can you think of 10 objects? Can you then list them in order of decreasing length? http://www.joemonster.org/gry/41805/Scale_of_the_Universe_2

Size Which is the smallest on your list? What size is it to the nearest order of magnitude?

Size The smallest objects that you need to consider in IB physics are subatomic particles (protons and neutrons). These have a size (to the nearest order of magnitude) of 10-15 m. ( 1 x 10-15m)

Size Which is the largest on your list? How large is it to the nearest order of magnitude?

Size The largest object that you need to consider in IB physics is the Universe. The observable Universe has a size (to the nearest order of magnitude) of 1025 m.

Let’s try and get our head around that! http://www.joemonster.org/gry/41805/Scale_of_the_Universe_2

On your paper can you estimate the masses of the largest and smallest objects you have written?

Mass The lightest particle you have to consider is the electron. What do you think the mass of the electron is? 10-30 kg! (0.000000000000000000000000000001 kg)

Mass We have already decided that the Universe is the largest object. What do you think its mass is? 1050 kg (100000000000000000000000000000000000000000000000000 kg)

Time Now think of 5 time intervals and put them in order (longest first) (For example, human lifetime, dog lifetime, time to walk home etc.)

Time The smallest time interval you need to know is the time it takes light to travel across a nucleus. Can you estimate it? 10-24 seconds

Time What’s the longest time interval you thought of?

Time The age of the universe. Any ideas?

Time The age of the universe. 12 -14 billion years 1018 seconds

Copy please! Size 10-15 m to 1025 m (subatomic particles to the extent of the visible universe) Mass 10-30 kg to 1050 kg (mass of electron to the mass of the Universe) Time 10-23 s to 1018 s (time for light to cross a nucleus to the age of the Universe)

A common ratio – Learn this! Hydrogen atom ≈ 10-10 m Proton ≈ 10-15 m Ratio of diameter of a hydrogen atom to its nucleus = 10-10/10-15 = 105

Estimation For IB you have to be able to make order of magnitude estimates.

Estimation/Guess What’s the difference?

Estimate the following: (to the nearest order of magnitude) The mass of an apple

Estimate the following: (to the nearest order of magnitude) The mass of an apple The number of times a human heart beats in a lifetime.

Estimate the following: (to the nearest order of magnitude) The mass of an apple The number of times a human heart beats in a lifetime. The speed a cockroach can run. A fast South American one!

Estimate the following: (to the nearest order of magnitude) The mass of an apple The number of times a human heart beats in a lifetime. The speed a cockroach can run. The number of times the earth will fit into the sun (Rs = 6.96 x 108 m, Re = 6.35 x 106 m)

Estimate the following: (to the nearest order of magnitude) The mass of an apple 10-1 kg The number of times a human heart beats in a lifetime. The speed a cockroach can run. The number of times the earth will fit into the sun (Rs = 6.96 x 108, Re = 6.35 x 106)

Estimate the following: (to the nearest order of magnitude) The mass of an apple 10-1 kg The number of times a human heart beats in a lifetime. 70x60x24x365x70=109 The speed a cockroach can run. The number of times the earth will fit into the sun (Rs = 6.96 x 108, Re = 6.35 x 106)

Estimate the following: (to the nearest order of magnitude) The mass of an apple 10-1 kg The number of times a human heart beats in a lifetime. 70x60x24x365x70=109 The speed a cockroach can run. 100 m/s The number of times the earth will fit into the sun (Rs = 6.96 x 108, Re = 6.35 x 106)

Estimate the following: (to the nearest order of magnitude) The mass of an apple 10-1 kg The number of times a human heart beats in a lifetime. 70x60x24x365x70=109 The speed a cockroach can run. 100 m/s The number of times the earth will fit into the sun (6.96 x 108)3/(6.35 x 106)3 = 106

Let’s do some more estimating!

Let’s do some more estimating! Earth’s mass = 6 x 1024 kg