From Michael.Savage at marsden.school.nz Sat May 3 20:09:58 2008 From: Michael.Savage at marsden.school.nz (Savage, Michael) Date: Sun, 4 May 2008 12:09:58 +1200 Subject: FW: re mythbusters video Message-ID: <98BBA63832B4CA47977BB451417E73A4029A33D5@smcs13.smc.local> For a really great clip showing max acceleration check out Top Gear's lads aboard the "Atom" http://www.youtube.com/watch?v=WaWoo82zNUA Cheers Mike Savage Samuel Marsden Collegiate School -----Original Message----- From: phys-teach-talk-bounces at nzip.org.nz [mailto:phys-teach-talk-bounces at nzip.org.nz] On Behalf Of David Housden Sent: Tuesday, 1 April 2008 1:34 p.m. To: phys-teach-talk at nzip.org.nz Subject: RE: re mythbusters video Hi Terry I haven't heard that Mythbusters did this but check out http://www.youtube.com/watch?v=yPHoUbCNPX8 - fantastic despite the fact it is in Japanese (actually I think it makes the clip even better) - I showed this to a number of groups last year - very good clip. A nice extra question to ask is about energy in terms of where has the kinetic energy "gone". Cheers David -----Original Message----- From: phys-teach-talk-bounces at nzip.org.nz [mailto:phys-teach-talk-bounces at nzip.org.nz] On Behalf Of Terry Moffat Sent: Tuesday, 1 April 2008 2:02 p.m. To: phys-teach-talk at nzip.org.nz Subject: re mythbusters video Hi, I hope someone can save me search time. Mythbusters did an experiment of firing a ball at 100 kph out the back of a moving vehicle travelling at 100 kph I gather it is somewhere on the net. Does anyone have the link? ta Terry Moffat _______________________________________________ Phys-teach-talk mailing list Phys-teach-talk at nzip.org.nz http://nzip.org.nz/mailman/listinfo/phys-teach-talk_nzip.org.nz No virus found in this incoming message. Checked by AVG. Version: 7.5.519 / Virus Database: 269.22.1/1352 - Release Date: 31/03/2008 10:13 a.m. No virus found in this outgoing message. Checked by AVG. Version: 7.5.519 / Virus Database: 269.22.1/1352 - Release Date: 31/03/2008 10:13 a.m. _______________________________________________ Phys-teach-talk mailing list Phys-teach-talk at nzip.org.nz http://nzip.org.nz/mailman/listinfo/phys-teach-talk_nzip.org.nz -- No virus found in this incoming message. Checked by AVG. Version: 7.5.519 / Virus Database: 269.22.1/1350 - Release Date: 30/03/2008 12:32 p.m. E-mail message checked by Spyware Doctor (5.5.0.178) Database version: 5.09520 http://www.pctools.com/spyware-doctor/ E-mail message checked by Spyware Doctor (5.5.0.178) Database version: 5.09520 http://www.pctools.com/spyware-doctor/ __________ Information from ESET NOD32 Antivirus, version of virus signature database 3072 (20080503) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com __________ Information from ESET NOD32 Antivirus, version of virus signature database 3072 (20080503) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com ##################################################################################### This e-mail message has been scanned for Viruses and Content and cleared by MailMarshal ##################################################################################### From dking at christscollege.com Thu May 8 07:00:54 2008 From: dking at christscollege.com (David King) Date: Thu, 8 May 2008 23:00:54 +1200 Subject: warm and cold winds Message-ID: <7805788C-C029-4A16-846E-265C96B0CBF9@christscollege.com> Can someone help? I got myself in a bit of a confuddle yesterday trying to answer a pupils question. "Sir, why, if temperature is to do with Kinetic Energy is wind cold?" I started on evaporation from the skin etc and the idea of us 'feeling' cold, when he asked "Why do we have warm winds? What's the difference?" I started to answer then stopped. What makes air particles travelling at whatever kph warm or cold? Cheers David King Physics HoD Christ's College Private Bag 4900 Christchurch New Zealand -------------- next part -------------- An HTML attachment was scrubbed... URL: http://nzip.org.nz/pipermail/phys-teach-talk_nzip.org.nz/attachments/20080508/e3027893/attachment.html From dhousden at xtra.co.nz Thu May 8 14:59:02 2008 From: dhousden at xtra.co.nz (David Housden) Date: Fri, 9 May 2008 06:59:02 +1200 Subject: FW: warm and cold winds Message-ID: <005c01c8b13d$94fc8e40$bef5aac0$@co.nz> Hi all I?m not sure this actually got sent to everyone so I will resend on David King?s behalf. Cheers David Housden From: phys-teach-talk-bounces at nzip.org.nz [mailto:phys-teach-talk-bounces at nzip.org.nz] On Behalf Of David King Sent: Thursday, 8 May 2008 11:01 p.m. To: PHYSICS TALK Subject: warm and cold winds Can someone help? I got myself in a bit of a confuddle yesterday trying to answer a pupils question. "Sir, why, if temperature is to do with Kinetic Energy is wind cold?" I started on evaporation from the skin etc and the idea of us 'feeling' cold, when he asked "Why do we have warm winds? What's the difference?" I started to answer then stopped. What makes air particles travelling at whatever kph warm or cold? Cheers David King Physics HoD Christ's College Private Bag 4900 Christchurch New Zealand No virus found in this incoming message. Checked by AVG. Version: 7.5.524 / Virus Database: 269.23.9/1419 - Release Date: 7/05/2008 7:46 a.m. No virus found in this outgoing message. Checked by AVG. Version: 7.5.524 / Virus Database: 269.23.10/1421 - Release Date: 7/05/2008 5:23 p.m. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://nzip.org.nz/pipermail/phys-teach-talk_nzip.org.nz/attachments/20080509/7101b9ff/attachment.html -------------- next part -------------- An embedded and charset-unspecified text was scrubbed... Name: ATT00069.txt Url: http://nzip.org.nz/pipermail/phys-teach-talk_nzip.org.nz/attachments/20080509/7101b9ff/attachment.txt From francis.Bryden at stcuthberts.school.nz Thu May 8 16:21:40 2008 From: francis.Bryden at stcuthberts.school.nz (Bryden, Francis) Date: Fri, 9 May 2008 08:21:40 +1200 Subject: warm and cold winds In-Reply-To: <005c01c8b13d$94fc8e40$bef5aac0$@co.nz> Message-ID: Hi David The way I think of it is.......... The temperature of the air (and the thermal energy your skin loses to it ) depends on the kinetic energy of the randomly moving particles. In warm air the particles have greater KE and so the skin loses less thermal energy because there is a smaller temperature gradient. I suspect the KE of the airparticles due to the wind is small compared with the KE due to their normal random motion. (Wind has no effect on the temperature of a thermometer. Point a fan at a thermometer and the effect is negligible.) Wind has two effects on us. We are usually warmer than the air, and there is a layer of warm air near our skin that we have heated up, this will keep us warm. Any wind will move this warm layer away. Because we sweat, wind will also cool us as it increases the rate of evaporation, taking thermal energy from our skin Thanks ................ Francis Francis Bryden HoD Physics St Cuthbert's College 122 Market Rd or Box 26 020 Epsom Epsom Auckland 1051 Auckland 1344 New Zealand New Zealand ph: 63 9 5204159 ext 7808 fbryden at stcuthberts.school.nz -----Original Message----- From: phys-teach-talk-bounces at nzip.org.nz [mailto:phys-teach-talk-bounces at nzip.org.nz] On Behalf Of David Housden Sent: Friday, 9 May 2008 6:59 a.m. To: phys-teach-talk at nzip.org.nz Subject: FW: warm and cold winds Hi all I'm not sure this actually got sent to everyone so I will resend on David King's behalf. Cheers David Housden From: phys-teach-talk-bounces at nzip.org.nz [mailto:phys-teach-talk-bounces at nzip.org.nz] On Behalf Of David King Sent: Thursday, 8 May 2008 11:01 p.m. To: PHYSICS TALK Subject: warm and cold winds Can someone help? I got myself in a bit of a confuddle yesterday trying to answer a pupils question. "Sir, why, if temperature is to do with Kinetic Energy is wind cold?" I started on evaporation from the skin etc and the idea of us 'feeling' cold, when he asked "Why do we have warm winds? What's the difference?" I started to answer then stopped. What makes air particles travelling at whatever kph warm or cold? Cheers David King Physics HoD Christ's College Private Bag 4900 Christchurch New Zealand No virus found in this incoming message. Checked by AVG. Version: 7.5.524 / Virus Database: 269.23.9/1419 - Release Date: 7/05/2008 7:46 a.m. No virus found in this outgoing message. Checked by AVG. Version: 7.5.524 / Virus Database: 269.23.10/1421 - Release Date: 7/05/2008 5:23 p.m. -------------------------------------------------------- This message (and any associated files) is intended only for the use of the individual or entity to which it is addressed and may contain information that is confidential, subject to copyright or constitutes a trade secret. If you are not the intended recipient you are hereby notified that any dissemination, copying or distribution of this message, or files associated with this message, is strictly prohibited. If you have received this message in error, please notify us immediately by replying to the message and deleting it from your computer. Messages sent to and from us may be monitored. -------------------------------------------------------- This email has been checked by Symantec Mail Security for Exchange. 08:21:42 Fri 09 May 2008 -------------- next part -------------- An HTML attachment was scrubbed... URL: http://nzip.org.nz/pipermail/phys-teach-talk_nzip.org.nz/attachments/20080509/d9c63337/attachment-0001.html From Peter.Gilberd at rsnz.org Thu May 8 17:57:39 2008 From: Peter.Gilberd at rsnz.org (Peter Gilberd) Date: Fri, 9 May 2008 09:57:39 +1200 Subject: warm and cold winds In-Reply-To: Message-ID: <60AD28B0581F38418917B12112D76A810616E23A1F@mail.rsnz.local> Hi all The following website quantifies Francis's statement that the KE of the air particles due to the wind is small compared with the KE due to their random motion: http://www.rwc.uc.edu/koehler/biophys.2ed/diffusion.html Wind velocity might be ~10 m / s. Random velocity of air particles is ~ 500 m / s. There is also rotational and vibrational energy stored in molecules; for a diatomic molecule such as nitrogen this accounts for approximately half the molecule's energy. Cheers Peter -------------------------------------------------------- Peter Gilberd Deputy Manager, Research Funding The Royal Society of New Zealand PO Box 598, Wellington 6140, New Zealand. Telephone (direct dial): +64-4-470 5778 Telephone (exchange): +64-4-472 7421 Fax: +64-4-473 1409 Email: peter.gilberd at rsnz.org The Gateway to NZ Science > -------------------------------------------------------- -----Original Message----- From: phys-teach-talk-bounces at nzip.org.nz [mailto:phys-teach-talk-bounces at nzip.org.nz] On Behalf Of Bryden, Francis Sent: Friday, 9 May 2008 8:22 a.m. To: David Housden; phys-teach-talk at nzip.org.nz Subject: RE: warm and cold winds Hi David The way I think of it is.......... The temperature of the air (and the thermal energy your skin loses to it ) depends on the kinetic energy of the randomly moving particles. In warm air the particles have greater KE and so the skin loses less thermal energy because there is a smaller temperature gradient. I suspect the KE of the airparticles due to the wind is small compared with the KE due to their normal random motion. (Wind has no effect on the temperature of a thermometer. Point a fan at a thermometer and the effect is negligible.) Wind has two effects on us. We are usually warmer than the air, and there is a layer of warm air near our skin that we have heated up, this will keep us warm. Any wind will move this warm layer away. Because we sweat, wind will also cool us as it increases the rate of evaporation, taking thermal energy from our skin Thanks ................ Francis Francis Bryden HoD Physics St Cuthbert's College 122 Market Rd or Box 26 020 Epsom Epsom Auckland 1051 Auckland 1344 New Zealand New Zealand ph: 63 9 5204159 ext 7808 fbryden at stcuthberts.school.nz -----Original Message----- From: phys-teach-talk-bounces at nzip.org.nz [mailto:phys-teach-talk-bounces at nzip.org.nz] On Behalf Of David Housden Sent: Friday, 9 May 2008 6:59 a.m. To: phys-teach-talk at nzip.org.nz Subject: FW: warm and cold winds Hi all I'm not sure this actually got sent to everyone so I will resend on David King's behalf. Cheers David Housden From: phys-teach-talk-bounces at nzip.org.nz [mailto:phys-teach-talk-bounces at nzip.org.nz] On Behalf Of David King Sent: Thursday, 8 May 2008 11:01 p.m. To: PHYSICS TALK Subject: warm and cold winds Can someone help? I got myself in a bit of a confuddle yesterday trying to answer a pupils question. "Sir, why, if temperature is to do with Kinetic Energy is wind cold?" I started on evaporation from the skin etc and the idea of us 'feeling' cold, when he asked "Why do we have warm winds? What's the difference?" I started to answer then stopped. What makes air particles travelling at whatever kph warm or cold? Cheers David King Physics HoD Christ's College Private Bag 4900 Christchurch New Zealand No virus found in this incoming message. Checked by AVG. Version: 7.5.524 / Virus Database: 269.23.9/1419 - Release Date: 7/05/2008 7:46 a.m. No virus found in this outgoing message. Checked by AVG. Version: 7.5.524 / Virus Database: 269.23.10/1421 - Release Date: 7/05/2008 5:23 p.m. ________________________________ This message (and any associated files) is intended only for the use of the individual or entity to which it is addressed and may contain information that is confidential, subject to copyright or constitutes a trade secret. If you are not the intended recipient you are hereby notified that any dissemination, copying or distribution of this message, or files associated with this message, is strictly prohibited. If you have received this message in error, please notify us immediately by replying to the message and deleting it from your computer. Messages sent to and from us may be monitored. ________________________________ This email has been checked by Symantec Mail Security for Exchange. 08:21:42 Fri 09 May 2008 -------------- next part -------------- An HTML attachment was scrubbed... URL: http://nzip.org.nz/pipermail/phys-teach-talk_nzip.org.nz/attachments/20080509/69338539/attachment.html From dking at christscollege.com Thu May 8 19:31:04 2008 From: dking at christscollege.com (David King) Date: Fri, 9 May 2008 11:31:04 +1200 Subject: warm and cold winds In-Reply-To: References: Message-ID: <3D2EF427-E83A-4E4D-B77F-ECC36FD50D7E@christscollege.com> Many thanks to all. A night's sleep and some clear explanations have helped greatly. Cheers David King Physics HoD Christ's College Private Bag 4900 Christchurch New Zealand On 9/05/2008, at 8:21 AM, Bryden, Francis wrote: > Hi David > > > > The way I think of it is???. > > > > The temperature of the air (and the thermal energy your skin loses > to it ) depends on the kinetic energy of the randomly moving > particles. > > > > In warm air the particles have greater KE and so the skin loses > less thermal energy because there is a smaller temperature gradient. > > > > I suspect the KE of the airparticles due to the wind is small > compared with the KE due to their normal random motion. > > > > (Wind has no effect on the temperature of a thermometer. Point a > fan at a thermometer and the effect is negligible.) > > > > Wind has two effects on us. > > > > We are usually warmer than the air, and there is a layer of warm > air near our skin that we have heated up, this will keep us warm. > Any wind will move this warm layer away. > > > > Because we sweat, wind will also cool us as it increases the rate > of evaporation, taking thermal energy from our skin > > > > > > > > > > > Thanks ................ Francis > > > > Francis Bryden > > HoD Physics > > St Cuthbert's College > > 122 Market Rd or Box 26 020 > > Epsom Epsom > > Auckland 1051 Auckland 1344 > > New Zealand New Zealand > > > > ph: 63 9 5204159 ext 7808 > > > > fbryden at stcuthberts.school.nz > > > > > -----Original Message----- > From: phys-teach-talk-bounces at nzip.org.nz [mailto:phys-teach-talk- > bounces at nzip.org.nz] On Behalf Of David Housden > Sent: Friday, 9 May 2008 6:59 a.m. > To: phys-teach-talk at nzip.org.nz > Subject: FW: warm and cold winds > > > > Hi all > > I?m not sure this actually got sent to everyone so I will resend on > David King?s behalf. > > Cheers > > David Housden > > > > > > > From: phys-teach-talk-bounces at nzip.org.nz [mailto:phys-teach-talk- > bounces at nzip.org.nz] On Behalf Of David King > Sent: Thursday, 8 May 2008 11:01 p.m. > To: PHYSICS TALK > Subject: warm and cold winds > > > > > > > Can someone help? > > > > > > > > > > I got myself in a bit of a confuddle yesterday trying to answer a > pupils question. > > > > > > > > > > "Sir, why, if temperature is to do with Kinetic Energy is wind cold?" > > > > > > > > > > I started on evaporation from the skin etc and the idea of us > 'feeling' cold, when he asked > > > > > > > > > > "Why do we have warm winds? What's the difference?" > > > > > > > > > > I started to answer then stopped. What makes air particles > travelling at whatever kph warm or cold? > > > > > > > > > > Cheers > > > > > > > > > > > > > > > David King > > > > > Physics HoD > > > > > Christ's College > > > > > Private Bag 4900 > > > > > Christchurch > > > > > New Zealand > > > > > > > > > > > > > > > > > > > > > > > > > > > No virus found in this incoming message. > Checked by AVG. > Version: 7.5.524 / Virus Database: 269.23.9/1419 - Release Date: > 7/05/2008 7:46 a.m. > > > > > No virus found in this outgoing message. > Checked by AVG. > Version: 7.5.524 / Virus Database: 269.23.10/1421 - Release Date: > 7/05/2008 5:23 p.m. > > > > > > > > This message (and any associated files) is intended only for the > use of the individual or entity to which it is addressed and may > contain information that is confidential, subject to copyright or > constitutes a trade secret. If you are not the intended recipient > you are hereby notified that any dissemination, copying or > distribution of this message, or files associated with this message, > is strictly prohibited. If you have received this message in error, > please notify us immediately by replying to the message and deleting > it from your computer. Messages sent to and from us may be monitored. > > > > This email has been checked by Symantec Mail Security for Exchange. > 08:21:42 Fri 09 May 2008 > _______________________________________________ > Phys-teach-talk mailing list > Phys-teach-talk at nzip.org.nz > http://nzip.org.nz/mailman/listinfo/phys-teach-talk_nzip.org.nz -------------- next part -------------- An HTML attachment was scrubbed... URL: http://nzip.org.nz/pipermail/phys-teach-talk_nzip.org.nz/attachments/20080509/e122f118/attachment-0001.html From mlsavage at paradise.net.nz Fri May 9 04:15:12 2008 From: mlsavage at paradise.net.nz (Mike & Martha Savage) Date: Fri, 09 May 2008 20:15:12 +1200 Subject: warm and cold winds Message-ID: <002801c8b1ac$ce2c4c40$a5964eca@savage01> "Warm" winds are simply the motion of air that has become warm (through contact with the ground, absorption of radiation and especially the latent heat of condensation). In the Southern Hemisphere warm winds are those that blow from the north ( from equatorial regions towards polar regions) In the Northern hemisphere it is the reverse with warm winds emanating from the south. Similarly "cold" winds are the movement of airmasses that have become cold through contact with colder surfaces and radiative losses. Southern hemisphere cold winds blow up from the south. Winds are excited and sustained by differences in pressure brought about by differential heating. The Earth's rotation induces a change in direction such that as air moves from high to low pressure it crosses the isobars at a shallow angle with a component towards the centre of low pressure. There is no significant heating of air masses due to their motion. Indeed, temperature is the kinetic energy of particles, but it is the particles vibrational motion at the molecular level that is at issue; the large scale motion of air streams is a different matter. Cheers Mike Savage Samuel Marsden Collegiate School Physics teacher (and long ago the meteorologist-in-charge at the Amundsen-Scott South Pole Station) ---------------------------------------------------------------------------- ---- From: phys-teach-talk-bounces at nzip.org.nz [mailto:phys-teach-talk-bounces at nzip.org.nz] On Behalf Of David Housden Sent: Friday, 9 May 2008 6:59 a.m. To: phys-teach-talk at nzip.org.nz Subject: FW: warm and cold winds Hi all I'm not sure this actually got sent to everyone so I will resend on David King's behalf. Cheers David Housden From: phys-teach-talk-bounces at nzip.org.nz [mailto:phys-teach-talk-bounces at nzip.org.nz] On Behalf Of David King Sent: Thursday, 8 May 2008 11:01 p.m. To: PHYSICS TALK Subject: warm and cold winds Can someone help? I got myself in a bit of a confuddle yesterday trying to answer a pupils question. "Sir, why, if temperature is to do with Kinetic Energy is wind cold?" I started on evaporation from the skin etc and the idea of us 'feeling' cold, when he asked "Why do we have warm winds? What's the difference?" I started to answer then stopped. What makes air particles travelling at whatever kph warm or cold? Cheers David King Physics HoD Christ's College Private Bag 4900 Christchurch New Zealand E-mail message checked by Spyware Doctor (5.5.0.178) Database version: 5.09790 http://www.pctools.com/spyware-doctor/ From g.foster at clear.net.nz Fri May 9 04:32:47 2008 From: g.foster at clear.net.nz (g.foster) Date: Fri, 09 May 2008 20:32:47 +1200 Subject: Cold and warm winds Message-ID: <48240c2f.22b.27ab.3689@clear.net.nz> Perhaps it is also relevant to remind ourselves of the special fohn winds we experience in the South Island and the reason why the West Coast area and Taranaki get so much rain. It is interesting that The northern slopes of Mt Taranaki actually is the wettest place in NZ, not the West Coast SI. When moist winds come across off the Tasman Sea they are forced upwards by the mountains. This causes the air to expand and there is a nett loss of kinetic energy of the particles as they spread out and slow down. This cooling causes the moisture to precipitate out as rain or snow or hail. When the drier air moves over the top of the Southern Alps it then descends and is compressed causing it to warm up since there is a gain of kinetic energy of the particles as they come closer together and speed up. This causes the hot dry Norwesters experienced in Canterbury. This is also the bais of a refrigerator which cools things down inside by compression of a gaseous substance, then allowing it to expand through a tiny hole. The rapid expansion causes the substance to cool down and this cooler substance then takes the heat from inside the fridge when heat flows from warmer substances to the cooling refrigerant. Then the whole sycle is repeated after the heat is transferred to the air in the vanes. Also heat pumps work in the reverse to a fridge. We 'experience' warm winds since the molecules have more random Ek and take less heat from our epidermal layer than if they are cool. Graham Foster Director of Science, EGGS AMI Learned Society From parkerprice at clear.net.nz Fri May 9 15:24:40 2008 From: parkerprice at clear.net.nz (Kerry Parker and Andy Price) Date: Sat, 10 May 2008 07:24:40 +1200 Subject: Cold and warm winds In-Reply-To: <48240c2f.22b.27ab.3689@clear.net.nz> References: <48240c2f.22b.27ab.3689@clear.net.nz> Message-ID: <0E95672DE7EC4FF0B394A497F07912CD@study> Graham's points are really interesting, as is the physics of weather. I didn't know that N Taranaki was wetter than the West Coast. How does that work then? Why N and not W? How does that work then? Is it a just a few km sq of Taranaki that is of concern here, or all the way from New Plymouth to the top of the mountain? The pressure changes in winds are complex too and I have only just started to think about what happens in NZ. How can a wind blow into a place where the pressure is higher (and hence heat up)? My very simplistic thinking is that the atmosphere has a pressure gradient increasing from space down to sea level due to gravity. Winds mostly run sideways from high to low pressure due to convection cells. Kerry --------------------------- Kerry Parker Senior Physics Teacher The Correspondence School ----- Original Message ----- From: "g.foster" To: Sent: Friday, May 09, 2008 8:32 PM Subject: Cold and warm winds > Perhaps it is also relevant to remind ourselves of the > special fohn winds we experience in the South Island and the > reason why the West Coast area and Taranaki get so much > rain. > It is interesting that The northern slopes of Mt Taranaki > actually is the wettest place in NZ, not the West Coast SI. > > When moist winds come across off the Tasman Sea they are > forced upwards by the mountains. > This causes the air to expand and there is a nett loss of > kinetic energy of the particles as they spread out and slow > down. This cooling causes the moisture to precipitate out as > rain or snow or hail. > > When the drier air moves over the top of the Southern Alps > it then descends and is compressed causing it to warm up > since there is a gain of kinetic energy of the particles as > they come closer together and speed up. This causes the hot > dry Norwesters experienced in Canterbury. > > This is also the bais of a refrigerator which cools things > down inside by compression of a gaseous substance, then > allowing it to expand through a tiny hole. The rapid > expansion causes the substance to cool down and this cooler > substance then takes the heat from inside the fridge when > heat flows from warmer substances to the cooling > refrigerant. > Then the whole sycle is repeated after the heat is > transferred to the air in the vanes. > > Also heat pumps work in the reverse to a fridge. > > We 'experience' warm winds since the molecules have more > random Ek and take less heat from our epidermal layer than > if they are cool. > > > Graham Foster > Director of Science, EGGS > AMI Learned Society > > _______________________________________________ > Phys-teach-talk mailing list > Phys-teach-talk at nzip.org.nz > http://nzip.org.nz/mailman/listinfo/phys-teach-talk_nzip.org.nz > From dking at christscollege.com Fri May 9 20:57:34 2008 From: dking at christscollege.com (David King) Date: Sat, 10 May 2008 12:57:34 +1200 Subject: Fwd: warm and cold winds References: Message-ID: <373532B9-7285-4EB2-90A1-4766B0A5DAA0@christscollege.com> Of course! After years of using mph though, kph seems more natural than kmph. In fact I cannot imagine saying "kay - em - pee - aitch" What do others write/say? David King Physics HoD Christ's College Private Bag 4900 Christchurch New Zealand Begin forwarded message: > From: David Porteous > Date: 10 May 2008 12:07:12 PM > To: "David King" > Subject: Re: warm and cold winds > > What a lot of responses this inquiry has received but David, kph oh > no kmph! > It's not 1000ph!!! > Another David > > David King wrote: > > > Can someone help? > > > I got myself in a bit of a confuddle yesterday trying to answer a > pupils question. > > > "Sir, why, if temperature is to do with Kinetic Energy is wind cold?" > > > I started on evaporation from the skin etc and the idea of us > 'feeling' cold, when he asked > > > "Why do we have warm winds? What's the difference?" > > > I started to answer then stopped. What makes air particles > travelling at whatever kph warm or cold? > > > Cheers > > > > > David King > Physics HoD > Christ's College > Private Bag 4900 > Christchurch > New Zealand > > > > > > > _______________________________________________ > Phys-teach-talk mailing list > Phys-teach-talk at nzip.org.nz > http://nzip.org.nz/mailman/listinfo/phys-teach-talk_nzip.org.nz > > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://nzip.org.nz/pipermail/phys-teach-talk_nzip.org.nz/attachments/20080510/3f178503/attachment.html