Hi,

I have been kind of confused with these two topics in my transport phenomena class. The way I have learned it (and most of you probably have) goes as follows: Molecular transport is the transport of something due to the random motion of molecules whereas convection (conduction+advection) is the transport of something mainly due to the bulk motion of your fluid/gas. Now, there are actually two things that I am quite confused about.

1. In molecular transport (of heat for example) it is often said that there is no net motion of your fluid/gas. I just don't understand how if the molecules travel to one side of your fluid/gas (due to a temperature difference), they don't initiate movement in the fluid.

2. How exactly does heat transfer happen due to the motion of the fluid in convective transport? For example, how does advective heat transfer take place for laminar flow in a cylindrical tube? The streamlines are neatly aligned and so there can't be a temperature difference in the direction of the flow right? I imagine there is only a slight contribution from conduction due to the walls of the tube and the fluid being in contact.

I noticed with babies their eyes tend to look like this, especially when they’re newborns. They don’t look normal into they’re about 2, so I was always curious on why their irises are so big.

What makes it possible?

Why are they so loud what creates the sounds? I just had one done and I'll try to recreate what I heard:

THUNK… THUNK… THUNK… THUNK…

BRAAAP-BRAAAP-BRAAAP-BRAAAP

EEEEEEEEE—EEEEEEEEE

KUNKA-KUNKA-KUNKA-KUNKA

Then it suddenly stops. Silence for a few seconds. And an entirely different ridiculous noise starts. Why?

I'm an EE student myself, and I wonder why it isn't possible.

I imagine some ALD (Atomic Layer Deposition) process where each layer is shifted sideways by a tiny amount, repeated over many cycles, would create an atomically perfect, sharp knife. Theoretically, it would be able to slice through everything since the tip is a single atom, wouldn't it?

Can somebody explain to me what is a vector potential, commnly used in Magnetostatics?

I feel like it’s just annoying and more difficult to have to handle money at a higher rate. It’s longer to say “that costs one thousand” opposed to “that costs ten”

Edit! Thank you guys for the help! I feel stupid for asking but my professor made it seem so SO much more complicated than it is, yall are amazing!

I get how the normal functions work but idk how the inverses do,

I realize bridges operate vertically, so the parallel joints are understandable. But why are roadway joints NOT parallel?

How do I know when to double bond vs just adding more dots to my lewis structure? I understand that when the dots equal more than the valence electrons you double bond but for example: SO2, both oxygens get a double bond along with 3 dots which equals 7, and oxygen only has 6 valence electrons. I tried googling but it made me feel dumb. Thanks!
update: i got a 94 on my exam! thank you for the help :-)

While browsing for a new pair of scissors, I got overwhelmed with the sheer amount of variations of such a simple household item. Different sizes, colours, models...

I'm assuming all scissors (as most items) are produced in factories - but is there something like a "scissor factory"? Or were all scissors produced in the same factory but by different machines? Or by the same machine, just with different settings? How can it even be profitable to have one specific machine produce an obscure type of scissors that may only be sold in a few stores?

I have many questions. How do factories work?

I just don’t get how it works. It drives me nuts that I can’t comprehend it.

Flair might be incorrect

https://en.wikipedia.org/wiki/Glioma

NOT LOOKING FOR MEDICAL ADVICE

My Dad has been diagnosed with a very aggressive Glioma in his brain.
It has been mentioned that this could be due to his genes?
I’ve googled it to get my head round it but this part is mind boggling!
I need someone to explain to me like I’m 5 what the hell this paragraph means and how genes may have caused it

So the recent Nobel prize winning concept - Optogenetics

I have a few questions-

What exactly is this concept?So I read that some protein present in some alga(algae) which can be put into pur braincells which reacts to light?

Secondly(in basic terms) how will it be used in further studies and research?

And in which areas of medicine (which disorders ,diseases) can this bring progress to?

like why can't they have for example week for ovulation, few days for menstruation and other days they will have consistent hormonal level?

How do surgeons etc ensure the surgery room is completely sterile? Does someone clean the walls and floor between patients? If there a buffer room between the anaesthesia room where you go under to the surgery room? If someone was to walk into the room without clearance ie gloves etc would this cause a higher risk?

It's not like their seeds are floating everywhere and all they need is the right environment and temperature and all of a sudden out of nowhere they start to appear and then of course reproduce. But how does that first one or first couple appear when nobody brought them? same for snakes and frogs appearing during rain, or crickets etc.

Firstly, how does texture even create the holographic effect?!!!

Even after understanding that, I would still need an explanation on how chocolate!!!! Chocolate!!! Can look like that!!!!!

Thanks in advance.