Sometimes I find the most elaborate ways of procrastinating when faced with a tedious task (this time, gathering all my grade data for my class together and doing the analysis to produce a final letter grade):
It is good when the distraction produces good and useful results, of course, and a 
tasty loaf of bread for later consumption is indeed a good result (it fell slightly in the rising, but…still good). Happily, early this morning I got my act together and finished the number crunching, produced the grade list and submitted it to the powers that be.
Now, free of my graduate electromagnetism class, I can get on to those other pressing tasks that I’d hoped to get done before the end of November…
-cvj
I recommend Abraham Pais’ “Subtle is the Lord”, for very readable insight into Einstein’s work in this area.
-cvj
So Einstein invented General relativity using maths which was already in existence yet very few people understood what he had done. Why was this? Was it perhaps because of the difference in notation between the mathematics and physics community?
I know nothing about this subject. Thanks.
-cvj
Would you say they are hard though? What are your views on the type of questions which are cooked up? I am guessing you’ve seen some.
I don’t know.
-cvj
i have another question, not sure where to post it…
Suppose you were given a bunch of questions from the physics olympiad with the same amount of time normally given to students who take it, how do you think you would do on them? It’s an interesting question because a) I think we’d all agree that they are hard questions but b) they are always given to students of a certain age and certainly never to professors.
cheers.
Women?! Heh. What an odd addition to your list.
Er… I’m afraid that you’ll have to wait like everyone else for my forthcoming memoir comparing my vast experience of the women of England to the women of “Cali”. It’s under contract and so I cannot discuss the details until the book, movie, and tv show are all ready to roll.
😉
Don’t hold your breath though. Got several other more pressing things to do first. Like perfecting my variation on that sweet potato biscuits recipe…
-cvj
Clifford, do you plan on coming back to live in England or staying in Cali, how does everything compare between the two? I am interested to know given that I live in England and have never gone to Cali but am curious to visit. By everything, I mean food, people, women, general costs etc
thanks
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“California or any other uni”
That is a very broad question, so my answer can only be very broad in return. I imagine that it is better than some courses, and not as good as others. The relevant thing is perhaps whether it is good for you and your needs, not whether it comes from some fancy university. You want to explore knowledge of a particular subject for its own sake and the open university has a wonderful history of allowing people to do that while getting on with other things like working, etc… in that respect, Berkeley or Harvard or Princeton are simply irrelevant.
Best,
-cvj
Clifford, I have embarked on an open university bsc course in maths in order to gain a better understanding of it. What is your opinion of the open uni? Would you see it as an inferior substitute to a degree from say California or any other uni?
Hi,
Equivalences:
(1) on the paper = in space
(2) make the paper infinite = make the space infinite
(3) So if it has no edges and is already of infinite extent, then it need not expand “into” anything. You just change the scale size…. make the distance between everything double what it was, and everything is twice as far apart. It is still infinite. I did not expand “into” anything in order to double in size.
There was no particle that exploded in any particular place.
By the way, there is no explanation for the big bang. We know it happened, and several of the properties of the universe around that time. We know that something like an inflationary period happened soon after, and so forth. We know that the universe does not need anything to expand into (you, as is common, are insisting on a geometrical situation that is simply not necessary, giving centers and edges and embedding spaces and so forth), and that it does not need a center or an exploding particle. But we do not know “why” it happened. That is an issue of ongoing research.
The mostly vast emptiness of atoms is just that…. mostly vast emptiness… in as much as the vacuum is vast emptiness… which it is and it isn’t, but that’s another story.
Best,
-cvj
Ah yes… but the dots are “on the paper”, therefore they are on something [or extending onto/into something]; however, if there is nothing there, how is something created or come into existence for the universe to expand into? Or, does the expansion itself create the “something” which the universe uses to expand into?
The same question is applicable to the Big Bang Theory, what was the “origin” of the particle which exploded, which resulted in our known universe. Acceptable explanations [based on data] are given for the Bang itself… but what was the origin of the, or does it matter?
What is ‘outside…? Albeit the distances are vast, they remain, at any given time, finite. Again, what’s outside… what are we expanding into?
Does anything that can be described as matter/substance exist in the emptiness of/inside the atom? As the atom/subatomic particles appear to resemble the universe, with the exception that the atom appears to be fixed in size [not expanding], but maybe it is, and it is expanding into a universe which is outside of itself, and we are similarly, expanding into a universe outside of our universe….. and it continues…. [Sort of an Edwin Abbott’s “Flatland”],
Yes, it would depend somewhat on the soil used. How about just experimenting and seeing what you get? You don’t need fertilizer. Look up the growing conditions for the herbs you are interested in, get some soil you like the look of that compares well to what the plants need, and try it. If it fails, try something else. It is fun to experiment with growing plants.
Enjoy!
-cvj
hi,
http://www.cleanairgardening.com/fertilizer.html
I have another different question on growing plants. If you look at this site you can see an array of different fertilisers and all manner of things which can be added to soil. This makes it very complicated. I am looking to grow my own parsley in small pots. Is it really that difficult? I just want some organic soil which I can use to grow it. My biggest concerns are growing herbs which taste nice and are nutritious. This might depend on the soil used?
HI,
I can’t do much more than this. You need to take what I explained above and work it into what you get from other sources: books, and so forth. I’m not going to be able to sit here and teach you the physics of every example you want to discuss… There are several good sources out there, and it is worth making the effort. I’ve given you a lot in the above to use as a basis for further exploration. I hope you understand.
Thanks.
-cvj
Hi Clifford,
I don’t know if Elizabeth might be asking, what if one were to travel to the edge of the universe, no matter how long it took or how fast you’d have to travel at, what would be ‘beyond the edge’?
In relation to entropy, how does your explanation apply to electrical current? Macroscopically we observe a ‘flow’ of current which we can use to our advantage. What is happening microscopically?
Similarly I don’t understand why a cup perched on a table would have higher entropy than one which was smashed on the floor?
What are the corresponding micro/macro states in this case and ‘why’ should there be more microstates for a given macrostate? I’m not sure if the pair of dice is a good example because if we were to do the experiment with the total 11 and 12, we would very likely get disimilar outcomes even though they both have the same entropy?
Carol,
An excellent observation!
Anne,
I must get this recipe of which you speak. Such wisdom!
-cvj
Hi Elizabeth,
The universe does not need to expand into anything in order to expand. Imagine a sheet of paper covered in dots. Make it a hugely large piece of paper whose edges are so far away that you don’t care about getting to them, or can’t. Well, I can expand that sheet of paper and see that happen locally without needing to worry about whether it is expanding “into” something. How do I see the expansion? The dots all move apart from each other.
Same goes for the galaxies in our universe.
Best,
-cvj
Hi,
Well, I’m sorry if it seemed like I was making light of your serious question, but it was hard to resist the baking jokes. So very sorry.
I don’t know what sources you were using to learn about entropy and the second law, and I cannot write you a textbook here as an answer to your question, so this might not be satisfactory. The key thing is to ignore most of the discussions about order and disorder and so forth that end up taking place when entropy is being discussed. It is confusing and misleading. A clean way to think of things is to understand the difference between microstates and macrostates. The latter is some macroscopic thing you measure, like the temperature of the air in the room, or maybe the pressure. A microstate is a given arrangement of air molecules that might give rise to that particular temperature, pressure, etc. There are many many microstates that can correspond to a given microstate. Think of a macrostate as the total score on two six-sided dice. You throw the dice and a two and a four come up and so the score is six. You can throw them again and a pair the threes comes up. Also six. So to different microscopic arrangements (microstates, 3+3 and 4+2 and 2+4) can give rise to the same macrostate (the total, 6). So far so good. Well, entropy is a measure of how many microstates there are for a given macrostate. It is larger the larger the number of microstates. So in our dice analogy, the outcome six has more entropy than the outcome twelve. Simple, right? Indeed, and this is all you need to understand why entropy seems to increase in a given situation. A system is exploring all its microstates, visiting them one by one and favouring no particular one over another. The air molecules are rearranging and exploring lots of different arrangements…. This is like exploring all the possibilities on the dice… So a higher entropy state is simply more likely, since it has more microstates corresponding to it, so the system will visit it more often. Keep throwing the six sided dice pair and although all outcomes have equal footing, the total six shows up more often than the total 12. There are just more ways of making 6 than 12. This explains lots of things about the “arrow” of nature…. Hot flows to cold and temperatures equalize because there are more microscopic arrangements of the molecules corresponding to that final outcome than there are the initial setup…. and so on and so forth. It is not really mysterious at all, and order and disorder really don’t come into it.
Best,
-cvj
About entropy, that’s an interesting question. I think the recipe says something like, “you can’t always get what you want.” But then it continues: “but sometimes. You just might find. You get what you knead.” I’m not really altogether sure what that means, but it sounds like sounds advice to me.
Actually Professor, in case you took my question as a joke, I was being serious. I was reading up on entropy and then the discussion turned to phase spaces and I became lost. So what is the idea with the 2nd law? Can quantum processes be observed in any given order whereas classical processes like a person being born are not ‘reversible’?
Dark matter ????
What is it that holds together, or that is outside of the universe?
The universe is expanding and thus, is finite in size at any given moment, therefore, what is it that is outside… what does the universe expand into? Could Dark Matter be the “it” which the universe expends into?E
And of course, a Baker’s Dozen is the result of Baker’s First Law: You get no more than you knead. : )
The loaf gets eaten before it can turn back. It is called Baker’s Second Law and has puzzled the finest culinary theorists for years. There was a seminal paper on the subject published in Bon Appétit some years back, but I don’t know the reference off hand.
-cvj
Professor, I have been reading up a bit on entropy but i am still not clear as to why entropy increases. Why is it that there is an order to the way things happen as time increases yet we never see a permutation of this order. We never see a loaf of bread turning back into flour and water. What is the idea behind this?
Hi,
I use many kinds of flour depending upon what I am making. For my most generic bread I mix wholemeal and white flour to make a bread that is not too heavy for slicing, sandwiches, etc.
Again, study and experiment with some recipes to see what works best for you.
Best,
-cvj
Do you use wholemeal organic non refined flour? In what sense is it better than the stuff you get in shops?
One reason for me to make my own pizza dough is that I can use wholemeal flour and avoid the chemicals which are invariably added by shops.
thanks.
I would hope that in making bread that the end result is not like the bread you (typically) buy in shops… I’d hope it would be way better.
I think that you’re brave to experiment randomly to make the pizza base, but I suggest that you simply look up a recipe and try that. The books I mentioned, or even more easily, a minute on google, will probably give you tried and tested suggestions. Then work out from there with your own variations once you’ve tried the basic one.
Enjoy!
-cvj
Actually I was trying to make a pizza and I assumed it was made using the same recipe as for making bread. Is this ok?
I did use yeast and knead it. I put the dough in a warm room and it did rise. But when I baked it, it just came out like a biscuit.
should the end result be like the bread you buy in shops?
Did you use yeast?
Did you knead the dough for a good amount of time? Raise it? Make sure everything was warm through the whole process? Hard to diagnose without further info.
You can find a basic bread recipe in any good general recipe book, such as The Joy of Cooking. If going more elaborate later, try Nancy Silverton’s La Brea Bakery book.
-cvj
they say bread making is art and science. Can you tell me the secret to getting the same quality bread in the shops? My last attempt resulted in a flat biscuit, nothing like bread.
It’s a fine tradition…!
-cvj
Now Zachary wants to follow in your footsteps and make bread after seeing this entry!