heat from sun

[swansont]

Okay, I was able to google that transfer of energy. This appears to be a site for children, and that is what I need to understand things. http://www.uwsp.edu/cnr/wcee/keep/Mod1/Rules/EnTransfer.htm

 

Here it says heat is a measure of how fast molecules are moving.

 

Now here comes the confusion again. Isn't all light photons? So when we name them we are talking about the speed they moving, not really different things? Then faster moving photons are carrying more transferred heat from the sun than slow moving photons? Or us there something else that makes the UV different besides speed? Why would one photon carry more transferred heat from the sun than slow moving photons? That is, if it is only transferred heat, why the difference?

 

Annoying kid

 

The site does a decent job of explaining, and does differentiate between heat and thermal energy. Heat is energy being transferred, while thermal energy is due to the motion of the molecules.

 

Photons all move at the same speed. They can have different energy, and this is related to their wavelength and frequency. [imath]E=h\nu = hc/\lambda[/imath]

 

UV photons have more energy (higher frequency, shorter wavelength), which is why they can do cellular damage — they can ionize atoms.

[Athena]

The site does a decent job of explaining, and does differentiate between heat and thermal energy. Heat is energy being transferred, while thermal energy is due to the motion of the molecules.

 

Photons all move at the same speed. They can have different energy, and this is related to their wavelength and frequency. [imath]E=h\nu = hc/\lambda[/imath]

 

UV photons have more energy (higher frequency, shorter wavelength), which is why they can do cellular damage — they can ionize atoms.

 

I love your explanations. But I no sooner get an ah, ha, and then think I don't comprehension everything yet. I just spent a half hour pondering the explanation, thinking of UV as the rabbit in a race with a hound, and taking 5 hops for every hound stride. I need to visualize the explanation or I just don't get it. I am also using my dictionary to better understand the terminology. This is a real mental exercise.

 

Could we liken UV to Shiva, the Hindu god of destruction and transformation? UV ionizes atoms, transforms them and causes damage.

Edited February 21, 2011 by Athena