John Cuthber

54 minutes ago, mar_mar said:

And I thought that dinosaurs could distinguish colors.

So what?

Had anyone said they couldn't?
 

52 minutes ago, mar_mar said:

If you mean that evolution still continues than where new homo sapiens evolved from chimpanzees?

Do you realise that humans did not evolve from chimps?
Nobody really thinks they did.

So, what you are doing is presenting a straw man argument.

So, once again...
 since this is a science site, I expect you to provide the extraordinary evidence for your extraordinary claim.

9 minutes ago, mar_mar said:

without evolution.

11 minutes ago, John Cuthber said:

And, since this is a science site, I expect you to provide the extraordinary evidence for your extraordinary claim.

11 minutes ago, mar_mar said:

Parrot trained by a human? Does that parrot know that the sky is "blue" and the grass is "green". What does it mean for it?

For teh sake of discussion, it's unlikely that Alex was ever told about a toy doll.
But if you showed him a green doll and asked what colour it was then (so I'm told) he would tell you it was green,
He could tell you that a coke can was red without needing to be told.

What Green meant to Alex was the same as it means to you or me.

1 minute ago, mar_mar said:

But animals already have an ability to "distinguish colors" without evolution. 

And, since this is a science site, I expect you to provide the extraordinary evidence for your extraordinary claim.

10 minutes ago, mar_mar said:

Animals don't distinguish colors, because they don't know the concept.

It can be dangerous to make absolute claims on science discussion boards.

"By the late 1980s, Alex had learned the names of more than 50 different objects, five shapes, and seven colors."

Alex was a parrot.

https://en.wikipedia.org/wiki/Animal_cognition
Being able to name the colour of an object means you understand the idea of colour.
The crucial test is naming the colour of an object which you had not previously seen.
I understand that Alex passed that test.

 

Science can't prove God because of this.
https://ericthegodeatingpenguin.com/

12 hours ago, Alfred001 said:

Ok, they say later on in the paper that they think there is good evidence that it doesn't have a significant carcinogenic effect in man.

Which isn't not to say there isn't one:

Which is what I have been saying all along.

You seem to have missed this.

12 hours ago, John Cuthber said:

If, as you suggest, the stuff is causing significant harm, how come things like the yellow card scheme (not to mention a stack of ambulance chasing lawyers) have not noticed it?

Can you let us know your explanation?

I'm still saying that, if the effect was big enough to matter, we would have found out about it.
To be blunt, we would have found out the same way we learned that there was a problem with thalidomide.
We would have noticed the victims.

Let's flip this on it's head.

If, as you suggest, the stuff is causing significant harm, how come things like the yellow card scheme (not to mention a stack of ambulance chasing lawyers) have not noticed it?
 

9 hours ago, StringJunky said:

I found some numbers from a heating firm on most comfortable humidity levels at given temperatures.

For an outdoor temperature over 50˚F, indoor humidity levels shouldn’t exceed 50%
With an outdoor temperature over 20˚F, indoor humidity levels shouldn’t exceed 40%
Outdoor temperature between 10˚F and 20˚F, indoor humidity levels shouldn’t exceed 35%
For an outdoor temperature between 0˚F and 10˚F, indoor humidity levels shouldn’t exceed 30%
Outdoor temperature between -10˚F and 0˚F, indoor humidity levels shouldn’t exceed 25%
With an outdoor temperature between -20˚F and -10˚F, indoor humidity levels shouldn’t exceed 20%
Outdoor temperature at -20˚F or lower, indoor humidity levels shouldn’t exceed 15%

https://lauryheating.com/ideal-home-humidity/

That's interesting.
Surely the outdoors is outdoors and I shouldn't care what the temperature there is.
On the other hand, if I'm worried about preventing condensation, those numbers make more sense.

If it's 15% RH indoors, you will get problems of dry eyes etc.

2 hours ago, StringJunky said:

. Dry-cold air is subjectively warmer than wet-cold air.

That's debatable at best.
https://www.cbc.ca/news/canada/edmonton/the-science-says-there-s-no-difference-between-a-dry-or-a-wet-cold-sorry-1.6268564

28 minutes ago, StringJunky said:

Walk from a clear area into a mist, you feel the heat draining off you.

Possibly because the reason why that area is misty is because it is cold.
Why else would there be mist there, but not elsewhere?

55 minutes ago, iNow said:

Water transfers heat against our bodies far more efficiently and intensely than air. 

Because it's over a thousand times denser.


Water vapour has a higher heat capacity than air, but a lower thermal conductivity.

If it's cold enough that you are not sweating (significantly) then the rate of evaporation is irrelevant to heat transfer. At 10C that probably applies.

It's well known that "other people's houses" feel colder for the same temperature- simply because you learn to avoid the drafts in your own house.

 

It's complicated but for most people (unless they are doing a lot of physical work, 10 degrees will be too cold.
And that will be the case regardless of humidity.

If you just heat up the air the relative humidity will fall and that will also add to comfort.
The "wasted" energy from a dehumidifier will warm the room and be beneficial anyway.
But a heater is cheaper to buy.

There are books about this.
https://en.wikipedia.org/wiki/Thermal_comfort

24 minutes ago, mar_mar said:

This is the point. If there's no colours viz. no humans, the wavelength doesn't matter. Who will measure the length? Who will witness the world? 

Animals also distinguish colours, but do they know that blue is "blue" and red is "red". For them it doesn't matter. 

For plenty of animals "red is ripe but green isn't" is relevant.

Colour is not the same as wavelength: discuss.


In the meantime , here is some music...

14 hours ago, nec209 said:

There some more left groups but they are mostly don’t get enough votes at lest in Canada and the UK on a federal level.

There are plenty of Left wing votes. The current government only got about 40% and you can assume they included pretty much all the Right wing.
The problem is our electoral system.
The biggest minority becomes an elected dictatorship.

5 hours ago, johnsri said:

Hello

How diode add voltage 1 diode give 111v and two diode 221V how diode add voltage  

Are you talking about this sort of thing?
https://en.wikipedia.org/wiki/Voltage_multiplier

11 hours ago, Sensei said:

..finally we have explanation of many things.. thank you so much for sharing this with us..

Apparently the problem is that you don't understand a hypothetical situation.
But yes, it does explain a lot

11 hours ago, grayson said:

What you know is that 2 hours ago, a higher being that knows about the future told you that in two up to four hours, a person will knock at your door and try to kill you.

At that point I called the local hospital and had myself admitted to diagnose the mental health issue.

6 hours ago, Sensei said:

STM (from the article that you just linked) is not one of them..

 

Thanks for letting me know that the microscopes I worked on in which electrons tunnelled giving a map of the surface electron fermi potential were not electron microscopes.
 

6 hours ago, Sensei said:

then you would not build an electron microscope, but a tunneling microscope

I'm not going to build a tunnelling proton microscope.
It's possible, but  much easier to use electrons.
Which is why scanning tunnelling electron microscopes are, in fact, electron microscopes.
(Wiki is not God)

These are electron microscopes too.
https://en.wikipedia.org/wiki/Field-emission_microscopy
They don't have electron guns (in the definition Sensei posted)
But they are tunnelling microscopes. The field emission relies on tunnelling.

6 hours ago, Sensei said:

A good starting point would be to create a 3D printer or 2D printer/plotter with high motion resolution (so that the electron gun remains stable and the sample moves slightly below).

Somehow, I think the folk who designed scanning electron microscopes  where pretty much the only  "moving part" was an electron beam, knew what they were doing.

 

4 hours ago, iNow said:

So is this 😉

24 minutes ago, Sensei said:

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

"Not to be confused with scanning electron microscope (SEM)."

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

"Not to be confused with Scanning tunneling microscope."

STM != SEM..

 

I wasn't aware that anyone had said that STM and SEM were the same.
Can you point out where they did so?

I obviously know they are different, you may recall that I pointed out that you can run one of them under water and that it doesn't have an electron gun.


The OP just said "electron microscopes".
That term includes TEM, STEM PEEM and SEM.

If I was an amateur trying to build an electron microscope, It'd build a tunneling one. (No high voltages, no vacuum chamber and also past experience of helping rebuild one about 1990)

12 hours ago, Sensei said:

Some people have been on the forum (any forum) too long and too bored with the forum and answering (newbie) people, they become unbearable and a cumbersome to the rest.. unable to answer any simple question.. We have seen this in the past.. Some of them were banned because they were too disruptive..

I'd call it professional forumer burnout..

Is that a reference to this?
 

On 11/18/2023 at 12:10 AM, swansont said:

They don’t measure the shape of electrons. 

12 hours ago, Sensei said:

Making an electron gun requires a fairly good vacuum.

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

Thankfully, not all electron microscopes use an electron gun.
The requirement for a vacuum is  last century's technology.
https://www.sciencedirect.com/science/article/abs/pii/0006291X91910328

 

12 hours ago, Sensei said:

Don't be silly. Electron microscopes are damn expensive and this is not a project you can do at home. At least not you..

Calling the newbies "silly" is a nice example of this.

 

12 hours ago, Sensei said:

Some people have been on the forum (any forum) too long and too bored with the forum and answering (newbie) people, they become unbearable and a cumbersome to the rest.. unable to answer any simple question.

But to be fair this
 

12 hours ago, Sensei said:

this is not a project you can do at home. At least not you..

is correct; just like I said.
 

13 hours ago, John Cuthber said:

You  haven't figured everything else out.

4 hours ago, grayson said:

I am going to ignore you not using common sense and explain what I meant. I mean the shape of multiple electrons. Like, how they form to show the shape of the subject.

I'm sorry you expressed yourself so badly.
The answer to your question is "it depends". There's several types of electron microscope and they use a variety of methods to form an image.
If you haven't figured out how to see that then I'm right. You  haven't figured everything else out.
 

13 hours ago, grayson said:

I have figured out everything except detecting the shape of the electrons.

If you think the shape of the electrons matters, then I very much doubt you have figured everything else out.

It's not a bad bet that the original apples were similar to what we call crab apples.
If they always bred true then they would still be crab apples.

It's important to distinguish the level of "sameness" that people seem to want in apples from that which they would get in nature.
For a lot of things, plants which are effectively siblings are close enough, but for our apples we want identical twins. There's a half-way house where we grow F1 hybrids for use.

So, for millennia our ancestors chose the biggest sweetest apples and in due course those apples' seeds were "planted" near human habitations (and well fertilised too).
So the treed that grew from them were biased in favour of big sweet apples and the offspring were subject to the same sort of pressure.


No need for Adam or Eve to understand genetics.
Once we started farming, we deliberately chose seed from plants that we liked.
But we discovered that apples don't breed true and they take ages to grow so it's a slow process to take pot-luck.
We found it's much more efficient to clone them.



 

Here's a list of varieties produced from Cox's orange pippin which were obtained by breeding them with other varieties.
https://en.wikipedia.org/wiki/Cox's_Orange_Pippin#Descendant_cultivars

One example is

Allington Pippin (Cox's Orange Pippin × King of the Pippins)
But it's important to realise that, if you fertilised flowers of one with the pollen of the other and grew the pips there's still no guarantee that the seeds would grow into anything like the Allington Pippin for essentially the same reason that you and your brother or sister are not identical.

Apples (and a lot of related fruit) are self-incompatible.

You can't get seed from a Cox's orange Pippin without crossing it with another variety.
So you can't raise them from seed.

If native varieties all bred true there wouldn't be any cultivated varieties.

7 hours ago, Peterkin said:

For a tree fruit, it wouldn't be no more than two or three generations.

If you are growing commercial apple trees there are no generations.
There are no seeds; it's all cloning.

And that's where we get the word "clone" from
 from Greek klōn ‘meaning twig’.

13 hours ago, Peterkin said:

No. Heirloom plants have been propagated through pollination by the same variety for generations.

I can believe you, or I can believe wiki
" while fruit varieties such as apples have been propagated over the centuries through grafts and cuttings. "

And I know that fruit trees won't "breed true".