Sunday 8 April 2012

1.35

1.35

15 March 2012

10:26
· 1.35 use the relationship between orbital speed, orbital radius and time period:

orbital speed = 2×Π×orbital radius

time period

v = 2×Π×r

T

v = 2×Π×r

T

v = orbital speed (m/s or km/hr)

r = orbital radius (m or km)

T = orbital period (s or hr)

1.35 Plenary Question

15 March 2012

10:29

Pearson, p.56, Q3+4

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· You also need to know that the radius of the Earth's orbit around the sun is 150,000,000km

1.35 Plenary Answers

15 March 2012

10:30

Pearson Answers, p.56, Q3+4

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Thursday 5 April 2012

1.36

1.36

15 March 2012

10:27
· 1.36 understand that:
· the universe is a large collection of billions of galaxies
· a galaxy is a large collection of billions of stars
· our solar system is in the Milky Way galaxy
[cid:image001.png@01CD126F.FC5B8AE0]

Comparative sizes of planets and stars

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Comparative sizes of galaxies

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Powers of 10 - Cosmic Voyage

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All of the scales of Physics

http://htwins.net/scale2/

Embed code to get live animation on your blog:

1.36 Space is big! Scale model of the solar system

12 May 2011

14:47
· Type the length of your classroom into cell B5 to get the solar system scaled to fit!
· Check out column U for information about the nearest star to our solar system!

>

Online version

http://www.exploratorium.edu/ronh/solar_system/

1.36 Plenary Answers

15 March 2012

10:30
1. What is the solar system?

Everything that orbits our local star, the Sun
2. What is the Milky Way?

The galaxy that contains our solar system
3. What is a galaxy?

A huge collection of billions of stars
4. How many galaxies are there in the Universe?

Billions

scale model.xls Download this file

1.33

1.33

15 March 2012

10:25
· 1.33 explain that gravitational force
· causes moons to orbit planets
· causes the planets to orbit the sun
· causes artificial satellites to orbit the Earth
· causes comets to orbit the sun
>

http://phet.colorado.edu/en/simulation/gravity-and-orbits


1. Turn on

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2. Experiment with the 4 different situations to see what orbits what and why

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3. Still not sure? Try

[cid:image003.png@01CD126F.F2FC4020]

1.32 and 1.34 Investigating the solar system - answers

Image001

1.32 and 1.34 Investigating the solar system - answers

16 March 2012

10:26

Moons
1. How are moons different from planets?

Planets orbit the Sun; moons orbit planets
2. The Earth has one moon. Do all planets?

No. Mercury and Venus have no moon, Mars has 2 and Venus and Saturn both have over 60 each!
3. Do moons have gravitational fields?

Yes, any body that has mass generates a gravitational field. The gravitational field strength on our Moon is

1.62N/kg, which is about 1/6 of the gravitational field strength on Earth.

Gravitational fields
4. Which planet has the largest gravitational field? What is it?

Jupiter = 26N/kg
5. Which planet has the smallest gravitational field? What is it?

Mercury = 4N/kg (Pluto doesn't count! See Q.11)
6. What is the relationship between the mass of the planet and the gravitational field strength of the planet?

The larger the mass of a planet, the stronger the gravitational field strength

Period of orbit
7. Which planet has the shortest period of orbit? What is it?

Mercury = 3 x Earth month = 0.25 x Earth year

(if you lived on Mercury you would be over 60 years old!)
8. Which planet has the longest period of orbit? What is it?

Neptune = 1978 x Earth month = 164 x Earth year

(if you lived on Neptune you would be 0.1 years old!)
9. What is the relationship between the period of orbit of a planet and its distance from the Sun?

The larger the distance from the Sun, the greater the period of orbit
10. What is the relationship between the surface temperature of a planet and its distance from the Sun?

The larger the distance from the Sun, the lower the surface temperature

(the one exception to this rule is Venus which has an exceptionally high surface temperature of +465oC due to an atmosphere of 96% CO2 and clouds of H2SO4!)

Classification of astronomical bodies
11. What 2 classifications are the planets grouped into? What are the key features of each group?

4 Inner "rocky" planets
o Rocky
o Smaller diameters
o Shorter periods

4 Outer "gas giant" planets
o Gaseous
o Larger diameters
o Longer periods
o Have rings (most noticeable for Saturn, but they all have them)
o What are 2 key features of comets and 3 key features of their orbits?
i. Made from ice and dust
ii. Have a tail when they pass close to the Sun
i. Highly elliptical orbit - see blue trace.

[cid:image001.jpg@01CD126F.E712EF20]
o Sometimes pass close to the Sun at very high speeds but spend most of their orbit in the outer reaches of the solar system moving at much lower speeds
iii. Periods can be from a few years to hundreds of thousands of years
13. How do the orbits of asteroids differ from the orbits of comets?

Asteroids are lumps of rock that mostly orbit the Sun in the "Asteroid Belt", between Mars and Jupiter, in approximately circular orbits
14. Which planet in the animation is no longer a planet? (it has been reclassified as a planetoid or dwarf planet)

Pluto was reclassified as a planetoid or dwarf in 2006 for reasons including its highly elliptical and tilted orbit

Tuesday 3 April 2012

IGCSE Physics Revision Resources Online

Dear Y11 students,

I’ve uploaded some revision resources onto Google docs for you. If you follow the links below you should be able to navigate just like with a normal folder structure.

EDEXCEL IGCSE Physics Past Papers

· https://docs.google.com/open?id=0B4X69CNkiSnAWWRfYmxfckdSemUydHZ6dUdIWnYtdw

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· Don’t forget to read the Read Me! file so that you appreciate the change in the style of the past papers that happened in 2011 https://docs.google.com/document/d/1BauFVy60j3f6gwt6pbBADtxRKMgbzfMQw9bR-OuXdyY/edit

· No mark schemes on there yet. I will share these with you after Songkran. E-mail me if I forget!

· I have already printed out paper copies of 2011 and Specimen Papers (2011) for you. You will get 2011 papers this week during your lesson and Specimen Papers (2011) in our lesson after Songkran

· IMPORTANT - It is far, far better to do a couple of past papers thoroughly then to rush through all of them and do them badly. So take your time and use the four step process that we’ve always used https://docs.google.com/document/d/1mgCyWklakcivjRS-OkfWC13UtBJwxdBQ78Me0N7omyY/edit

Other revision resources

· https://docs.google.com/open?id=0B4X69CNkiSnAWXl3T0c2TW9TN1NaNXk3ODBvVHNrUQ

[cid:image002.png@01CD10E0.61D88170]

Remember that your concentration starts to decrease rapidly after more than about 30mins study so make sure that you take a short (5 min) break every half an hour. Break for just long enough to make a drink or eat a piece of fruit – DO NOT check Facebook! (or you’ll still be there 3 hours later… ☺!)

After exam leave starts I’m happy to give you any help that I can. I will usually be available when you normally have Science lessons (unless I’m invigilating) but please check with me first so you don’t have a wasted trip into school. Face to face contact is much more effective than trying to teach you via e-mail so please e-mail for help only as a last resort.

Best wishes,

Matt Baker
Physics Teacher and Samui House Leader
Bangkok Patana School
P Please consider the environment before printing this email.

643 Lasalle Road (Sukhumvit 105) Bangna Bangkok 10260 Thailand
Tel: +66 (0) 2 398 0200
Fax: +66 (0) 2 399 3179
Email: maba@patana.ac.th
Science Blogs:
http://maddog9physics.posterous.com/
http://maddog10physics.posterous.com/
http://maddog11physics.posterous.com/
http://maddogibfizziks.posterous.com/
Samui House Blog:
samuireddragons.posterous.com

Thursday 29 March 2012

1.32 and 1.34

1.32 and 1.34 Starter

16 March 2012

10:18

Tell the person next to you…
· the names of the 8 planets in our solar system (in order!)

Answers
1. Mercury (closest to the sun)
2. Venus
3. Earth
4. Mars
5. Jupiter
6. Saturn
7. Uranus
8. Neptune (furthest from the sun)

How can you remember this?
· "My Very Educated Mother Just Served Us Nothing"
· "My Very Easy Method Just Speeds Up Naming (Planets)"

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1.32 and 1.34 Starter 2 - Quick Planets quiz

12 May 2011

15:52
>

1.32 and 1.34 Investigating the solar system - answers

16 March 2012

10:26

Moons
1. How are moons different from planets?

Planets orbit the Sun; moons orbit planets
2. The Earth has one moon. Do all planets?

No. Mercury and Venus have no moon, Mars has 2 and Venus and Saturn both have over 60 each!
3. Do moons have gravitational fields?

Yes, any body that has mass generates a gravitational field. The gravitational field strength on our Moon is

1.62N/kg, which is about 1/6 of the gravitational field strength on Earth.

Gravitational fields
4. Which planet has the largest gravitational field? What is it?

Jupiter = 26N/kg
5. Which planet has the smallest gravitational field? What is it?

Mercury = 4N/kg (Pluto doesn't count! See Q.11)
6. What is the relationship between the mass of the planet and the gravitational field strength of the planet?

The larger the mass of a planet, the stronger the gravitational field strength

Period of orbit
7. Which planet has the shortest period of orbit? What is it?

Mercury = 3 x Earth month = 0.25 x Earth year

(if you lived on Mercury you would be over 60 years old!)
8. Which planet has the longest period of orbit? What is it?

Neptune = 1978 x Earth month = 164 x Earth year

(if you lived on Neptune you would be 0.1 years old!)
9. What is the relationship between the period of orbit of a planet and its distance from the Sun?

The larger the distance from the Sun, the greater the period of orbit
10. What is the relationship between the surface temperature of a planet and its distance from the Sun?

The larger the distance from the Sun, the lower the surface temperature

(the one exception to this rule is Venus which has an exceptionally high surface temperature of +465oC due to an atmosphere of 96% CO2 and clouds of H2SO4!)

Classification of astronomical bodies
11. What 2 classifications are the planets grouped into? What are the key features of each group?

4 Inner "rocky" planets
o Rocky
o Smaller diameters
o Shorter periods

4 Outer "gas giant" planets
o Gaseous
o Larger diameters
o Longer periods
o Have rings (most noticeable for Saturn, but they all have them)
o What are 2 key features of comets and 3 key features of their orbits?
i. Made from ice and dust
ii. Have a tail when they pass close to the Sun
i. Highly elliptical orbit - see blue trace.

[cid:image002.jpg@01CD0CEF.A99DF1B0]
o Sometimes pass close to the Sun at very high speeds but spend most of their orbit in the outer reaches of the solar system moving at much lower speeds
iii. Periods can be from a few years to hundreds of thousands of years
13. How do the orbits of asteroids differ from the orbits of comets?

Asteroids are lumps of rock that mostly orbit the Sun in the "Asteroid Belt", between Mars and Jupiter, in approximately circular orbits
14. Which planet in the animation is no longer a planet? (it has been reclassified as a planetoid or dwarf planet)

Pluto was reclassified as a planetoid or dwarf in 2006 for reasons including its highly elliptical and tilted orbit

planets quiz.swf Download this file

1.21

Image001

1.21

Tuesday, July 06, 2010

3:04 PM
· 1.21 use the ideas of momentum to explain safety features
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Example

Explain how motorcycle and bicycle helmets can protect their users during a collision

Answer
· Helmet or bare head, the change in momentum of your head during a collision is equal
· With a helmet, this change in momentum takes place over a longer time
· This means that the force needed to change the momentum of your head is less

or use the equation
· Impulse = Δp = F x t where Δp = constant
· cushioning in helmet => increases t
· and therefore decreases F

1.21 Plenary answers

13 March 2012

15:20

Physics for You p.147 Q2c

2c. Why is the front of a car designed to collapse in a serious collision? (3 marks)


· There is a force when you crash that decelerates the car (decreases your momentum)
· If the front of the car collapses (this is the crumple zone), this force acts for a longer time than if the front of the car were rigid
· This means that the force needed to change the car's momentum is less and there's less risk of injury to the driver

or use the equation
· Impulse = Δp = F x t where Δp = constant
· crumple zone increases t
· and therefore decreases F