Archive | April 2016

Endothermic and Exothermic Reactions: What’s the Difference?

images (33)Endothermic and exothermic may sound similar but are complete polar opposites of each other. Depending on what chemicals and or conditions are in a certain system, it will be either endothermic or exothermic. Although we may not think about it, endothermic and exothermic are always happening in our everyday lives.

Coming from the greek roots of “exo” meaning outside and “therm” meaning heat, exothermic reactions are reactions that release heat from its system into its immediate surroundings. When exothermic reactions occur, the immediate surroundings of the reactions gain energy becoming hot while the system itself loses energy becoming cold. This is the case because when the reaction occurs, heat is the product so if the system releases energy, so the immediate surrounding area will be hot. When exothermic reactions occur, the reactants yield the products plus heat. In an exothermic reactions the reactants have more energy that the products meaning the We see reactions that are exothermic in our everyday life, like something as obvious as a hot compression pad but there are many other everyday things we encounter. The flame of a candle is exothermic because the energy is being released into the immediate surrounding while the system loses energy. Other examples of exothermic reactions are the formation of ice, mixing water with acids, and nuclear fission. Exothermic reactions are very useful being that the methane combustion in our gas stoves, the combustion of the gas in our cars, and the use of dynamite that mines our coal, are all exothermic reactions. Also, cellular respiration is exothermic.

Endothermic reactions, being the complete opposite of exothermic reactions, comes from the greek roots of “endo” meaning within and “therm” meaning heat. Endothermic reactions absorb heat from the immediate surroundings into the system making the immediate surroundings colder because of the lesser amount of energy previously there. This is the case because when the reaction occurs, energy is needed to make the product so it takes the surrounding energy making the surroundings cold. In endothermic reactions, the reactants and energy yield the products. Endothermic reactions like baking bread, the production of sugar in photosynthesis, and cooking an egg are all things that we experience in our everyday lives and are very important. The most important endothermic reaction is the evaporation of water which we use to sweat which is a way to maintain homeostasis and not pass out and die. Also, obviously cold packs are endothermic being that when mixing the two chemicals in the bag, it becomes cold.

 

This entry was posted on April 25, 2016, in Education.

Scientific Paradigms And Universal Truths

download (44)Some have argued that existing scientific paradigms are pretty meaningless since they keep changing. I wouldn’t quite consider currently existing paradigms meaningless. We only exist in this brief era so whatever this era’s paradigms are helps us come to terms with this era’s version of reality, otherwise known as our current understanding of life, the Universe and everything. The same applied to those living in the pre-relativity / pre-quantum paradigm. The same applied pre-Newton. Ditto those existing in any pre-Copernican era. The same will apply for those trying to come to terms with reality decades, centuries, millennium from now.

Science isn’t about absolute truth (or ultimate answers), again, because what’s true today may be falsified tomorrow; paradigms change and evolve. Science appears to be rather about providing the best explanation possible in the here and now; a better explanation than that was provided yesterday; ideally providing an even better explanation tomorrow.

So science is an ever unfolding, ongoing, evolving an unveiling of reality, which is how I like to see science. Science can’t be a quest for the truth since what is considered true today can always be falsified at a later date. So IMHO science is just the quest to come to terms with the nature of reality as best it can, given the circumstances it finds itself in at any given time. For example, before the inventions of the telescope and the microscope, our version and vision of reality was more restricted than after-the-fact.

So, what is true? What is truth? Is there any absolute universal truth?

Actually there is one and only one thing that you (no matter how much science you read or do) can consider to be true, and that is that you (i.e. – your mind) exists. That aside, there’s no absolute truth anymore in [Einstein’s] Relativity. That is, one person may see events A & B simultaneously; another person sees A before B; a third person sees B before A. So, what’s the truth of the matter?

If you travel into a Black Hole, as you cross the event horizon time seems to flow at one second per second; to an external observer you’re crossing the event horizon as would the flow of molasses in an Antarctic winter! What’s the truth of the matter?

Before you look, is Schrodinger’s Cat dead or alive? What is the truth about the state of the Cat?

Is it true that Antarctica is cold? If you are a human in your birthday suit, then yes. If you are a penguin then not so much. But compared to the concept of Absolute Zero, Antarctica is really quite tropical!

Is it true that Pi has a value? If so, what is it?

Once might suggest that the speed of light (in an absolute vacuum) is an absolute truth, except that we don’t know for absolute certain that the speed of light has been constant over cosmic time intervals.

Is it true that the Universe extends infinitely in all directions? If so, if that is true, how could you or anyone else for that matter ever prove it? Actually I quite accept the idea and that there could be lots of expanding and contracting universes (i.e. – a Multiverse) within this postulated infinite Cosmos, but how could an infinite Cosmos be proven to be an absolute truth?

Isn’t gravity or the force of gravity a universal and absolute truth? But can that be entirely true since while a theoretical graviton particle might convey the force of gravity, it itself doesn’t have any mass and has no gravity in and of itself. Further, I’ve read speculations regarding the Multiverse concept (many individual universes within this infinite Cosmos) that the laws, principles and relationships of physics could be quite different in each universe even to the point where it’s not inevitable that there is a graviton or any gravity in some universes within the Multiverse. Even in a universe without gravity particles could still form into atoms and atoms into molecules and molecules up to whatever structures that are consistent with being held in place by electromagnetism (assuming that exists in this hypothetical universe). In fact positive – negative attraction is a form of pseudo-gravity. So what might be an absolute universal truth(s) across a Multiverse?

Back to gravity. Is it absolutely true that if you drop an apple it will fall towards the ground? Well no, since it is theoretically possible that all of the relevant forces could against all probability but not against all possibility push the apple upwards. In a similar fashion, it’s not true that you can’t walk through a solid brick wall. If you’re willing to wait trillions of years, quantum probabilities are such that you could quantum tunnel through a brick wall and live (you and wall both totally intact) to tell the tale.

Once upon a time it used to be scientifically true that: dinosaurs were sluggish, their tails dragged behind them, they were cold-blooded, and couldn’t out-think a fly; all swans were white; Jupiter just had four moons and no rings; the Sun went around the Earth; there was a vital life force; there were just four elements (air, earth, fire and water); stones couldn’t fall from the sky; comets were harbingers of gloom and doom; there were hundreds of (pseudo) snake-oil medical treatments for ailments that really treated nothing of the sort; Venus had a natural satellite (Neith); unicorns, dragons and related really existed.

In that spirit I predict that one day the ‘truth’ that the expansion rate of the Universe is accelerating will be falsified.

Earlier I asked what might be an absolute universal truth(s) across a Multiverse?

I have my own trilogy of absolute truths. 1) Something cannot be created from nothing. 2) Causality rules absolutely*. 3) Something cannot both be and not at the same time and in the same place. In fact something cannot both be and not at the same time – full stop. But not everyone agrees with my absolute truths so maybe the best that can be said is that each person has his or her own version of ‘the truth’.

There are of course logical truths that are true based of exact definitions. For example, it’s absolutely true based on accepted definitions that you can’t have a spherical cube. There are also mathematical truths as in two parallel lines will never intersect no matter how far they are extended in Euclidian space. Of course no one has ever performed the actual test of that to verify that absolute truth, but that’s just quibbling.

But “truth” is a rather slippery word or concept and philosophers have had a field day over discussing it. I rather doubt philosophers, or even professional scientists for that matter, really expect there to be such a thing as one and only one version of universal truth. Perhaps it’s best to avoid the word, apart from that lone absolute truth that you (i.e. – your mind) exists.

My preferred phrase is “what is the nature of reality?” since one reality (i.e. – Mother Nature’s reality) can incorporate several versions of ‘the truth’ (i.e. – Einstein’s Relativity).

*And therein lies my other absolute truth – motion. I’ve already argued that time is nothing but change and change is nothing but motion, but causality also requires motion. Motion therefore is to my way of thinking the most fundamentally absolute property that the Cosmos has.

Science librarian; retired.

 

Sound in Space

images (32)Similar to how light or heat travels, sound travels in waves. What we call “sound” are actually vibrations in the air. In empty space, there is no air, which means that no sound can be produced. Light waves and radio waves do exist in space, however, that is because light does not need air to travel. Since light can travel in space, there is no problem is seeing light, but when it comes to sound a radio must be sent to translate any sound that may be connected with the light waves.

Unless they are in their spacecraft, astronauts in space cannot talk to one another, seeing as there is a lack of air. When astronauts are spacewalking, radios in their helmets allow them to communicate with each other since radio waves are not sound, and can actually exist in space. While some argue that already existing gases in space could propagate sound, just like Earth’s air allows sound to travel, it is highly unlikely that we would be able to hear them. The difference is that gas clouds are much less dense than the Earth’s atmosphere. If sound were to travel through a gas cloud, our ears not being sensitive enough, wouldn’t hear the sound. A large, sensitive microphone could detect the sounds, but our human ear will always hear silence. Space is a vacuum where gases are released into space and expand very quickly while their density decreases. This fact, disproves all movies with explosions in outer space. While an exploding ship would realize gases and sound could technically travel along them, the gases would spread rapidly and lose density quickly, that the sound would deb too faint to hear. Then again, it also depends on distance.

Sound will always need a medium to travel through, whether it be a gas, a liquid or a solid. Sound traveling through a liquid, or even better, a solid, will always be better than sound traveling through gas. The molecules in solids are packed very tightly. Liquids are not packed as tightly as solids, and gases are very loosely. Heat can also be a big component to how fast sound can travel. The hotter the weather is, the more the molecules will bump into each other and the fast sound will travel.

While sound does not travel in outer space, we have ways of interpreting any small vibrations that may occur not loud enough for the human ear to hear.

 

This entry was posted on April 12, 2016, in Education.