Zakaj se vroča juha ohladi in zakaj nas pozimi zebe?... Show more
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Updated Apr 20, 2026
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Prenos toplote: Načini in razlage
1 / 5
Uvod v prenos toplote
Toplota se vedno prenaša s toplejšega telesa na hladnejše - nikoli obratno! To je ena od osnovnih naravnih zakonitosti, ki jo opazuješ vsak dan.
Toplota (Q) je energija, ki prehaja med telesi z različnimi temperaturami. Pazi - to ni isto kot temperatura (T), ki nam pove, kako "vroče" ali "hladno" je nekaj. Toplota je pot, temperatura pa cilj.
Toplotni prevodniki (kot so kovine) odlično prenašajo toploto, medtem ko toplotni izolatorji (stiropor, zrak) to počnejo počasi. To je razlog, zakaj je kovinska žlica v juhi vroča, stiroporna skodelica pa ostane hladna.
Pomembno: Prenos toplote se ustavi šele, ko dosežeta telesi toplotno ravnovesje - isto temperaturo.
Prevajanje (kondukcija)
Predstavljaj si delce kot ljudi v vrsti, ki si podajajo žogico, ne da bi se premaknili s svojega mesta. Tako deluje prevajanje toplote.
Delci na toplejšem delu močneje nihajo in s trki predajajo energijo počasnejšim sosedom. Ta prenos poteka brez gibanja snovi - samo energija "skoči" naprej.
Prevajanje je najbolj učinkovito v trdnih snoveh, še posebej v kovinah. Zakaj? Ker imajo kovine proste elektrone, ki zelo hitro prenašajo energijo po celotnem kosu.
Pozor: Ko se dotakneš vroče plošče ali ko se kovinska žlica segreje v juhi - to je prevajanje v akciji!
Konvekcija (tokovanje)
Konvekcija je kot prevoz z dvigalom - topla snov se dviga, hladna pada, in tako nastane kroženje. To deluje samo v tekočinah in plinih.
Ko segrevamo vodo v loncu, se spodnji sloj segreje in postane manj gost (lažji). Dvigne se navzgor, medtem ko se hladnejša voda spusti navzdol. Temu pravimo konvekcijski tok.
Radiator v tvoji sobi deluje prav tako - segreje zrak okoli sebe, ta se dvigne, hladen zrak pa se spusti in se tudi segreje. Tako se celotna soba postopoma ogreje.
Ključno: Brez gibanja snovi ni konvekcije - zato v trdnih snoveh ni mogoča!
Sevanje (radiacija)
Sevanje je edini način prenosa toplote, ki ne potrebuje snovi - potuje lahko tudi skozi vakuum! Deluje z elektromagnetnimi valovi.
Vsako telo nad absolutno ničlo oddaja toplotno sevanje. Višja je temperatura, več sevanja oddaja. Ko to sevanje zadene drugo telo, se del energije absorbira in telo se segreje.
Temne in hrapave površine bolje vpijajo in oddajajo toploto kot svetle in gladke. Zato poleti nosiš svetla oblačila, pozimi pa temna.
Zanimivost: Toplota Sonca potuje 150 milijonov kilometrov skozi prazen vesolja prostor, preden te segreje!
Praktični primeri in povzetek
V resnici se vsi trije načini prenosa toplote pogosto dogajajo hkrati. Radiator je odličen primer - oddaja toploto s konvekcijo (segreje zrak), prevajanjem (če se ga dotakneš) in sevanjem (čutiš toploto na razdalji).
Termovka je genijalna, ker preprečuje vse tri načine: vakuum ustavi prevajanje in konvekcijo, posrebrena površina zmanjša sevanje, zamašek pa prepreči uhajanje.
Za teste zapomni:
- Prevajanje: Trdne snovi, stik delcev (kovinska žlica)
- Konvekcija: Tekočine/plini, kroženje snovi (radiator)
- Sevanje: Tudi vakuum, elektromagnetni valovi (Sonce)
Osvoji to: Toplota ≠ temperatura. Toplota je energija v gibanju, temperatura pa lastnost telesa!
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This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
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Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
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Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Prenos toplote: Načini in razlage
Zakaj se vroča juha ohladi in zakaj nas pozimi zebe? Vse se dogaja zaradi prenosa toplote, ki poteka na tri fascinantne načine. Razumevanje tega ti bo pomagalo razložiti ogromno stvari iz vsakdanjega življenja!
Uvod v prenos toplote
Toplota se vedno prenaša s toplejšega telesa na hladnejše - nikoli obratno! To je ena od osnovnih naravnih zakonitosti, ki jo opazuješ vsak dan.
Toplota (Q) je energija, ki prehaja med telesi z različnimi temperaturami. Pazi - to ni isto kot temperatura (T), ki nam pove, kako "vroče" ali "hladno" je nekaj. Toplota je pot, temperatura pa cilj.
Toplotni prevodniki (kot so kovine) odlično prenašajo toploto, medtem ko toplotni izolatorji (stiropor, zrak) to počnejo počasi. To je razlog, zakaj je kovinska žlica v juhi vroča, stiroporna skodelica pa ostane hladna.
Pomembno: Prenos toplote se ustavi šele, ko dosežeta telesi toplotno ravnovesje - isto temperaturo.
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Prevajanje (kondukcija)
Predstavljaj si delce kot ljudi v vrsti, ki si podajajo žogico, ne da bi se premaknili s svojega mesta. Tako deluje prevajanje toplote.
Delci na toplejšem delu močneje nihajo in s trki predajajo energijo počasnejšim sosedom. Ta prenos poteka brez gibanja snovi - samo energija "skoči" naprej.
Prevajanje je najbolj učinkovito v trdnih snoveh, še posebej v kovinah. Zakaj? Ker imajo kovine proste elektrone, ki zelo hitro prenašajo energijo po celotnem kosu.
Pozor: Ko se dotakneš vroče plošče ali ko se kovinska žlica segreje v juhi - to je prevajanje v akciji!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Konvekcija (tokovanje)
Konvekcija je kot prevoz z dvigalom - topla snov se dviga, hladna pada, in tako nastane kroženje. To deluje samo v tekočinah in plinih.
Ko segrevamo vodo v loncu, se spodnji sloj segreje in postane manj gost (lažji). Dvigne se navzgor, medtem ko se hladnejša voda spusti navzdol. Temu pravimo konvekcijski tok.
Radiator v tvoji sobi deluje prav tako - segreje zrak okoli sebe, ta se dvigne, hladen zrak pa se spusti in se tudi segreje. Tako se celotna soba postopoma ogreje.
Ključno: Brez gibanja snovi ni konvekcije - zato v trdnih snoveh ni mogoča!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Sevanje (radiacija)
Sevanje je edini način prenosa toplote, ki ne potrebuje snovi - potuje lahko tudi skozi vakuum! Deluje z elektromagnetnimi valovi.
Vsako telo nad absolutno ničlo oddaja toplotno sevanje. Višja je temperatura, več sevanja oddaja. Ko to sevanje zadene drugo telo, se del energije absorbira in telo se segreje.
Temne in hrapave površine bolje vpijajo in oddajajo toploto kot svetle in gladke. Zato poleti nosiš svetla oblačila, pozimi pa temna.
Zanimivost: Toplota Sonca potuje 150 milijonov kilometrov skozi prazen vesolja prostor, preden te segreje!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Praktični primeri in povzetek
V resnici se vsi trije načini prenosa toplote pogosto dogajajo hkrati. Radiator je odličen primer - oddaja toploto s konvekcijo (segreje zrak), prevajanjem (če se ga dotakneš) in sevanjem (čutiš toploto na razdalji).
Termovka je genijalna, ker preprečuje vse tri načine: vakuum ustavi prevajanje in konvekcijo, posrebrena površina zmanjša sevanje, zamašek pa prepreči uhajanje.
Za teste zapomni:
- Prevajanje: Trdne snovi, stik delcev (kovinska žlica)
- Konvekcija: Tekočine/plini, kroženje snovi (radiator)
- Sevanje: Tudi vakuum, elektromagnetni valovi (Sonce)
Osvoji to: Toplota ≠ temperatura. Toplota je energija v gibanju, temperatura pa lastnost telesa!
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
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The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user