Questions

What is the difference between evaporating and boiling?

Boiling is rapid evaporation anywhere in the bulk liquid and at a fixed temperature called the boiling point and requires continuous addition of heat.
The rate of boiling is limited by the rate of heat transfer into the liquid.
Evaporation takes place more slowly than boiling at any temperature between the melting point and boiling point, and only from the surface, and results in the liquid becoming cooler due to loss of higher kinetic energy particles.

Questions

Why do solids keep their shape and why don't liquids and gases ?

As solids have a tightly packed formation and cannot move around and there is very strong bonds between particles, where as liquids and gases don't have a regular formation and can move around, so they are able to change shape.
Why do solids and liquids have a fixed volume but gases can spread out to fill their container?

As gases have no attracting forces between the particles and no fixed shape or volume, where as solids and liquids do have stronger bonds between particles and solids have a fixed shape and both have a fixed volume.

5.7 and 5.8

Instructions for Objective 5.7 and 5.8

1. 5.7 and 5.8 Starter. Find out the names of the processes. Research on the internet if necessary. No need to blog this.

2. 5.7 and 5.8. Forward this e-mail to your blog and type the answers into the e-mail.

3. 5.7 and 5.8 Experiment. I’m afraid you can’t do the expt until we get back but watch the video clip to see how it’s set up and have a look at the graph of the results.

4. 5.7 to 5.10 Plenary 1. Play the attached “States of Matter”

5. 5.7 to 5.10 Plenary 2. Play the attached “Fill the trucks”

6. PhET States of matter simulation - embedding into your Posterous blog. Embed in your blog and then have a play

5.7 and 5.8 Starter

28 October 2011

11:00
· What are the 6 processes shown by the arrows?
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Solid ----> liquid = melting
Liquid ----> Gas = evaporating Gas -----> liquid = condensing Liquid ---->solid = freezing
Solid ----->Gas = reverse sublimation Gas ----> solid = sublimation

5.7 and 5.8

28 October 2011

10:20
· 5.7 understand that a substance can change state from solid to liquid by the process of melting
· 5.8 understand that a substance can change state from liquid to gas by the process of evaporation or boiling
· Questions from Collins p.112
· Answer in Bullet Points!
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· Use following pages from Collins as a resource to help you
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5.7 and 5.8 Experiment - Cooling Curve of Stearic Acid using datalogger

15 October 2010

14:34

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5.7 to 5.10 Plenary 1

28 October 2011

12:19

· Play the Stage 1 game to test your knowledge of solids, liquids and gases
· Play the Stage 2 game to test your knowledge about changes of phase!

5.7 to 5.10 Plenary 2

28 October 2011

12:19

Play the Level 1 game to test your knowledge of the properties of solids, liquids and gases

Extension: Play the Level 2 game to extend your knowledge about changes of phase!

PhET States of matter simulation - embedding into your Posterous blog

28 October 2011

11:14
· Create a post
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· Turn on HTML editor
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· Copy in this text and Publish

Click to Run

· Success! Now have a play with the simulation...
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states of matter drag and drop plenary.swf Download this file

Fill the trucks - Properties of s,l,g.swf Download this file

5.9 and 5.10 starter

s,l,g animation.swf Download this file

States.docx Download this file

states 1.docx Download this file

5.6 Questions

Collins, p.107

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Note: ρfresh water = 1,000kg/m3; g = 10N/kg

Q5: Pressure difference = height x density x strength of gravitational field P = hxpxg
150 = h x 1000 x 10
h = 15m if he was in seawater he would be slightly less then 15m under sea level Q6: Pressure difference = height x density x strength of gravitational field P = hxpxg
increase in pressure = 24.4 kPa the total pressure = 189.4 kPa

5.6

Correction as follows...

· 5.6 recall and use the relationship for pressure difference:

pressure difference = height × density × g
∆p = h × ρ × g

∆p = pressure of the fluid (N/m2 or Pa)
h = height of the fluid (m)
ρ = density of the fluid (kg/m3)
g = gravitational field strength (N/kg)

5.6 Demo - squirting water column

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· The bottom hole squirts water the furthest
· Because the water at the bottom has the greatest pressure
· Because in the formula ∆p = h × ρ × g, ρ is constant, g is constant and h is large
· So ∆p = large

5.6

· 5.6 recall and use the relationship for pressure difference:

pressure difference = height × density × g

∆p = h × ρ × g

∆p = pressure of the fluid (N/m2 or Pa)

h = height of the fluid (m)

ρ = density of the fluid (kg/m2)

g = gravitational field strength (N/kg)

5.5 Demo 2 - Collapsing Bottle

· Collapsing Bottle

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5.5 Demo 1 - Magdeburg Hemispheres

5.5 Demo 1 - Magdeburg Hemispheres

12 October 2011

07:19
· Magdeburg Hemispheres

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· And here are the horses I was talking about! http://www.youtube.com/watch?v=7bJkaFByiA0&feature=related

: 5.5

· 5.5 understand that the pressure at a point in a gas or liquid which is at rest acts equally in all directions

5.4 Starter 2 explained

animation - why a drawing pin works.swf Download this file

5.4 Starter 2 explained

· Your finger pushes on the pin and the pin pushes back on your finger
· N3L tells us that all these two forces are equal in size
· The pin pushes on the wall and the wall pushes back on the pin
· N3L tells us that all these two forces are also equal in size
· If the surface area is large then the force is spread over a large area and the pressure is low
· If the surface area is small then the force is spread over a small area and the pressure is high
· You would like the pressure on your finger to be low and the pressure on the wall to be high
· The other way round is painful!

5.4 Model answers to Written questions

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Answers to written questions.ppt Download this file

See the full gallery on Posterous

5.4 Starter

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Starter.ppt Download this file

See the full gallery on Posterous

5.4

Pressure Formula.ppt Download this file

· 5.4 recall and use the relationship between pressure, force and area:

pressure = force / area

p = F / A

Untitled

How to figure out the density of an irregular solid

m = 7.3g
V= 3.5 ml
p =m/v
p = 2.1 g/cm(cubed)

Answers

Model Answers to Density Harder Questions.ppt Download this file

5.2 Harder Questions

________________________________________
From: Matt Baker
Sent: Friday, October 07, 2011 8:42 AM
To: Andrew Koomenjoe Nyaga; Arisara Amrapala; Boondaree Chang; Chrischawit Chomsoonthorn; Christopher Lo; Connor Blair Sailes; Frazer Allen Briggs; Huei-Yu Daniel Lo; Isabel Catriona McDonald; Kavin Supatravanij; Luke Michael Gebbie; Lydia Anna Foley; Morrakot Sae-Huang; Puchawin Borirackujarean; Qing Tang; Sanyam Grewal; Sebastien Grimm; Soo Hyun Lee; Tatiksha Singh; Usa Wongsanguan; Yanida Areekul; Yi-Lin Huang
Cc: maddog11physics@posterous.com
Subject: 5.2 Harder Questions ((nogallery))

5.2 Harder Questions

07 October 2011

07:46
· Collins p.106 Q.1-3. (Table of densities below)

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wood in oil- depends on what sample of material you have Wood in mercury- wood will float
plastic in oil -platic will sink
steel in mercury - steel will float
silver in air- silver will sink
gold in mercury - gold will sink
helium ballon in air- will float

3. gold is more dense than silver so if the crown is pure gold the m= 1930 v= ?
Density = 19.3
Density = m/v
v= m/d
v = 1930 / 19.3
V= 100 if it is pure gold if it is less than pure gold the volume will be higher

Helpful equations

Solve for density: d = m/v Solve for mass: m= dv Solve for volume: V= m/d

5.3 Plenary 2 Corrected!

· How can you make a cannonball float?

Explanation below…

Density of Iron = 7.9g/cm3 or 7,900kg/m3

Density of Mercury = 13.6g/cm3 or 13,600kg/m3

5.3 Plenary

Drag'n'Drop Density (in kg per m3).swf Download this file

Remember: 1g/cm3 = 1,000kg/m3

: 5.3 Plenary 2

· How can you make a cannonball float?

Explanation below…

Density of Mercury = 7.9g/cm3 or 7,900kg/m3

Density of Iron = 13.6g/cm3 or 13,600kg/m3

5.2 Starter 2 - Moon Rock

Density starter - Moon Rock.ppt Download this file

The person on the right is correct

Unit 5 keywords

nrojujhrgbajortbgojlrebrowjael.doc Download this file

P5 Keywords

Unit 5 Keywords and Mixed Definitions.doc Download this file

5.2 Plenary Answer

· If you take a piece of wood that's got a density of 2.4g/cm3 and cut it exactly in half, what will the density of each of the 2 new pieces of wood be?

· 2.4g/cm3!
· You've halved the mass of each block but you've also halved the volume of each block, so the ratio m/V remains contant!
· For example…
· ρbig block = m/V = 240/100 = 2.4g/cm3
· ρsmall block = m/V = 120/50 = 2.4g/cm3

5.2

Density formula.ppt Download this file

· 5.2 recall and use the relationship between density, mass and volume:

density = mass / volume

ρ = m / V

5.3

Density Practical - regular and irregular solids and liquids.ppt Download this file

· 5.3 describe how to determine density using direct measurements of mass and volume

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5.2 Starter

Density of gases - Mythbusters breath it in!

P5 student objectives sheet

IGCSE Physics Student Objectives for Unit 5 - New Specification.doc Download this file

Untitled

M = 575.2 W= 5 cm, l = 5 cm h= 2cm
V= w x l x h = 5x5x2 = 50cm3
P = m/v = 575.2/ 50 = 11. 504 g/cm3

Review of test

Corrections:

1. Explain how an extra blanket blanket on your bed reduces the heat transfer from your body to your bedroom: Traps air, reduces conduction, blanket insulator

2. A disadvantage of burning wood instead of coal in a power station is that alot of land is lost, animals lose their habitat

3. three non-renewable sources that are used to produce electricity in power stations are nuclear, oil, and natural gas

4. a device that turns sound energy to electrical energy is a microphone

5. TOTAL energy at the start is equal to the TOTAL energy at the end

6. Force is measured in newtons
7. when cycling some energy is transferred to heat in the body and friction