Archive for the ‘Science’ Category
This week on SciByte we throw science at a few Old Wives Tales … and see what sticks. Plus we take a look at the science that makes them true, false or somewhere in between.
Direct Download Links:
|SciByte iTunes Feeds:||SciByte RSS Feeds:|
iPad & Apple TV Video
|HD Video RSS
Large Video RSS
Mobile Video RSS
MP3 Audio RSS
Do you really catch a cold by getting cold?
- No : The flu and the common cold are caused by viruses
- Origins : Both the cold and the flu tend to be seasonal, which is probably why cold weather took all the ‘heat’.
- When it is cold outside ..
- People tend to stay inside and are more likely to spread germs to one another.
- People are exposed to each other more in the winter than in the summer
- School is in session, kids are around each other all day
- There is also evidence now that viruses spread more easily through dry air.
- Hypothermia, not just being cold, suppresses immunity
- There are conflicting results on weather or not simple cold air exposure compromises the immune system, some experiments even show that cold air exposure stimulates the immune system
The Common Cold …. resistance is futile
- There is still no known treatment that shortens the duration.
- It does spontaneously resolve in 7–10 days, although symptoms can last up to three weeks
- Average contraction rate is 2–4 times a year for an adult, and 6–12 for a child
- Although it may produce nausea, the “stomach flu” is NOT acutally the flu virus, but gastroenteritis
- Typically transmitted through the air by coughs or sneezes that cause aerosols containing the virus, it can also be transmitted through direct contact with bird droppings, nasal secretions, or contaminated surfaces
Speaking of cold weather and protecting yourself …
Do you really lose most of your body heat from your uncovered head?
- Actually it depends on the circumstances.
- Origins : US army survival manual from 1970 which strongly recommended covering the head when it is cold, since “40 to 45 percent of body heat” is lost from the head.
- At least as recent as 2008 the US Army Survival Guide has the same warning about head protection in cold weather.
- How did they get that? : An interpretation of the data from an experiment by the US military in the 1950s that had volunteers dressed in Arctic survival suits and exposed to bitterly cold conditions. Because the only part of their bodies left uncovered was their heads, most of their heat was lost through there.
- It’s still a good idea to cover your head in cold weather, it does hold your brain!
- Thermoregulation : The blood vessels in your limbs and extremities will react by constricting in the cold to preserve the heat to you ‘core’ systems. Since the brain is a core system, the blood vessels do not constrict and your body continues to try to keep your brain the same temperature.
Attention! Thermodynamics has entered the webshow
- The fundamental modes of heat transfer are:
- Conduction or diffusion : The transfer of energy between objects that are in physical contact
- Convection : The transfer of energy between an object and its environment, due to fluid motion ( in this case fluid also referees to gasses, like the air)
- Radiation : The transfer of energy to or from a body by means of the emission or absorption of electromagnetic radiation
- Mass transfer : The transfer of energy from one location to another as a side effect of physically moving an object containing that energy
- While you are standing in cold air the main mode of heat transfer is convection, although any physical contact you have with an object colder than you introduces conduction as well
- In convection the amount of heat you loose per unit time is determined by the objects heat transfer coefficient the difference in the temperature and the area exposed
- dQ / dt = -h * A ΔT
- Conduction also relies upon material coefficients, difference in temperature and the size and shape of the object.
- In the case of the US military experiments above, the Arctic suits provided a barrier that slowed the rate of convection from the persons body to the air; however the head had no such barrier. Therefore the head was able to conduct the body’s heat unimpeded.
But if ALL the brain is where the science happens …
If we need ‘all’ portions of our brain … what about people who have had segments of there brain removed?
- Hemispherectomy—where half the brain is removed
- Generally used to treat debilitating seizure disorders that do not respond to medication
- Unbelievably, the surgery has no apparent effect on personality or memory
- Disconnects communication between the two hemispheres, preventing the spread of seizures to the functional side of the brain.
- Only in cases where the benefits of removing the problems caused (electrical or otherwise) by an afflicted portion of the brain outweigh the benefits that remain in the afflicted side of the brain.
Not THAT kind of hemi …
- All hemispherectomy patients suffer at least partial hemiplegia on the side of the body opposite the removed or disabled portion, and may suffer problems with their vision as well.
- Hemiplegia : total paralysis of the arm, leg, and trunk on the same side of the body
- It is almost exclusively performed in children because their brains generally display more [neuroplasticity](http://en.wikipedia.org/wiki/Neuroplasticity, allowing neurons from the remaining hemisphere to take over the tasks from the lost hemisphere
- Left Side of Brain and speech
- It was thought at one time that if you took it after the age of two you would never talk again
- It has been shown that while most people have problems with their speech, the younger the patient the less disability there is
Do you get cramps from swimming just after you eat?
- NOTE : Drowning is a leading cause of accidental deaths in infants and children
- However, the thought that a sandwich or any snack will cause you to sink like a stone is FALSE
- Possible Origins
- The thought that eating caused high blood flow to the stomach would cause low blood flow to limbs
- In the 50’s and 60’s there were fewer lifeguards to it is possible that parents simply wanted to be able to relax during lunch time without worrying.
Whoever Charley is … I hate him and his horse
- Muscle cramps are unpleasant sensations caused by muscle contractions or over shortening.
- They can be caused my a variety of things, including muscle fatigue, low sodium, and low potassium
- While none of the following have been conclusively proven to help, there is anecdotal evidence that most people under the grip of a cramp are willing to try.
- alternatively tensing and relaxing the afflicted muscle, stretching, massage, heat, water, electrolytes, banana, Vitamin B, orange juice
Food, glorious food!
- In the stomach hydrochloric acid both kills most contaminating microorganisms and begins the mechanical break down of foods
- While there may be an increase of blood flow to the stomach wile is is ‘churned’ in the stomach that has no direct correlation to muscle contractions in your limbs
So the kids aren’t going to drown just because they ate a PB&J, what determines boy vs girl
If your belly is round it’s a girl and oval like a football it’s a boy…
- There have been many theories throughout history about guessing the baby’s gender
- With so many body shapes really … chances are slightly higher for a boy
- The gender of your baby is determined by whether the fertilizing sperm has an X or a Y chromosome. An X chromosome will lead to a girl, a Y to a boy.
I’m tired after dealing with the kids at the pool, and I want to read before bed time …
Reading in dim light or sitting too close to the TV damages your eyes.
- Dim light might make it difficult for the eyes to focus, which can cause short-term eye fatigue.
- Challenging visual work, such as reading in insufficient light, can also lead to short-term drying of eyes because you blink less often.
- You can’t damage your eyes by using them, unless you stare into the sun.
- FYI : Getting too close to the set for your favorite shows won’t harm your eyes – “either from overfocusing or from radiation”
Ow! My eye!
- Asthenopia / eye strain : When concentrating on a visually intense task, the [ciliary muscle],(http://en.wikipedia.org/wiki/Ciliary_muscle) tightens, it’s the eye muscle that helps you focus and controls blood flow to certain parts of your eye.
- Giving the eyes a chance to focus on a distant object at least once an hour usually alleviates the problem.
- A CRT computer monitor with a low refresh rate or a CRT television can cause similar problems because the image has a flicker. Aging CRTs also often go slightly out of focus, and this can cause eye strain. LCDs do not go out of focus and are less susceptible to visible flicker.
We spend some time looking at time, how we have measured it’s passage throughout history, philosophically, how it’s affected by gravity, and the very concept of time itself.
Plus find out why Einstein proposes that we travel through time at the speed of light, how Atomic clocks work, and is it possible gravitational fields warp time?
All that and more, on SciBye!
Direct Download Links:
|SciByte iTunes Feeds:||SciByte RSS Feeds:|
iPad & Apple TV Video
|HD Video RSS
Large Video RSS
Mobile Video RSS
MP3 Audio RSS
- “Time is what keeps everything from happening at once.” – Ray Cummings, Sci-Fi Author
- Smallest units of time = Planck time [time it takes for light to travel the shortest distance current theories can handle]
- Why do we always move forward?
- Is time eternal, or a side effect of “space”?
Philosophy on the Nature of Time:
- Immanuel Kant believes time is all in our heads, as a necessity to quantify sensory inputs of everyday existence. Also believes in predestination, and that Free Will can only exist outside of Time.
- Martin Heidegger believes similarly, and that humans should be capable of “stepping out of time” by a specific form of non-associative thinking. The past, present and future can become one within our minds, and experienced in random order. (uhm, excuse me?!?)
- Henri Bergson believed that Time could not be measured because it is infinite and malleable, and shapes itself to the perceptions of an individual.
- “Time is an illusion” is a common saying in Buddhist teachings.
- HG Wells: “There is no difference between time and any of the three dimensions of space except that our consciousness moves along it.” — The Time Machine
- C. S. Lewis “The future is something which everyone reaches at the rate of 60 minutes an hour, whatever he does, whoever he is.” (but do those min pass by at the same rate)
‘When’ was the Start of the Universe, T=0 point
Measurement ‘devices’ through history
- Mayan’s : Mayan Calender created during the Dark Ages in Europe
- Earth orbit @ 365 days [Actual = 365.2422 days, 0.06%]
- Lunar Month @ 29.53086 days [Actual = 29.53059 days; 0.0009%]
- Mercury orbit @ 117 days [Actual = 116 days; 0.86%]
- Venus orbit @ 584 days [Actual = 583.92 days; 0.01%]
- Mars orbit @ 780 days [actual = 779.936 days; 0.008%]
- Antikythera mechanism - is an ancient mechanical computer designed to calculate astronomical positions. It was recovered in 1900–1901 from the Antikythera wreck. Its significance and complexity were not understood until decades later. Its time of construction is now estimated between 150 and 100 BC. The degree of mechanical sophistication is comparable to a 19th century Swiss clock. Technological artifacts of similar complexity and workmanship did not reappear until the 14th century, when mechanical astronomical clocks were built in Europe
A day – 24 hours?
- 2 Radio telescope set on different points of Earth measure a radio wave from a quasar. They line up once a ‘day’ which is not always 24 hours [changes are in mili seconds]
- In certain elements [like Cesium] the Electrons will ‘jump’ between orbits and emit a flash of light at precise intervals [Cesium, 9 billion times a sec] Video
- Such a clock, if sent on a space shuttle, ticks at a different speed. Because it is further from Earth’s gravitational pull.
- Einstein proposes that we travel through Time at the speed of light.
- Einstein: Spacetime is a single entity, not separate things. And because of the mixing of space & time, time ticks differently for separate entities, based on relative speeds.
- The faster you travel through space, the slower you travel through time.
- Proven by the Shapiro effect (blip in Mercury’s orbit, measured on opposite sides of the Sun)
- Gravitational fields warp time
- blip in Mercury’s orbit, measured on opposite sides of the Sun – VIDEO
If time is flexible based on observation, then all of it always exists…
- (Incorrect for quantum mechanics)
- New theories suggest that “spacetime” is granular, and not fixed. On a large scale it looks like a single thing, but it actually flows as it is being created, in the future.
Black holes actually STOP time at their event horizon, to an outside observer.
But an observer falling in would see time speed up around them, the closer they got.
High speed camera moments
CPT – Charge, Parity, and Time Reversal (CPT) Symmetry
Download & Comment:
This week on SciByte …
We look at the results from Gravity Probe B and how they relate to Einstein’s predictions on mass, space, time and how they all interact with one another. We’ll also open up the guts of that crazy contraption, and discuss some of the impressive tech that made the whole experiment possible to begin with.
Direct Download Links:
|SciByte RSS Feeds:|
-Sir Issac Newton [Mathematician]
-1687 – His predictions predicted the existence of Neptune based on the motions of Uranus
-Mercury’s Orbit hower can NOT be explained by Newtonian math alone, but was resolved with Einsteins general theory of relativity in 1915
-Newtonian Calculations however still are accurate enough for most applications
-General Relativity – Albert Einstein [1907-1915] The observed gravitational attraction between masses results from their warping of space and time.
→ Space-Time is not flat, but can be stretched and warped by matter
-What this means, boiled down: Time moves slower under gravity
-A device for measuring or maintaining orientation, based on the principles of conservation of angular momentum.
-Video : Gyroscope
-Video : Conservation of Angular Momentum : Spinning Skater
-“A” confirmed the prediction that gravity slows the flow of time, and the observed effects matched the predicted effects to an accuracy of about 70 parts per million. [1976, and lasted <2hours]
-Used a hydrogen maser, a highly accurate frequency standard, to measure the rate change of a clock in lower gravity with high precision.
-A star, a telescope, a spinning sphere [conceived in 1959, launched in 2004, decommissioned in Dec 2010] [A Star, telescope, and space time]
-Gravity Probe B Cutaway
-Reference telescope sighted on IM Pegasi, a binary star in the constellation Pegasus
-Drag Free System
-Solar Radiation Pressure – Particles streaming away from Sun transferring momentum
-Atmospheric Drag [@624KM]
-Compensation done with helium boosters, full 6-degree motion (first ever)
-London moment gyroscopes
-A spinning superconductor generates a magnetic field whose axis lines up exactly with the spin axis of the gyroscopic rotor.
-Are housed in a dewar of superfluid helium @ a temperature of under 2 kelvins (−271 °C, −456 °F)
-A magnetometer determines the orientation of the generated field, which is interpolated to determine the axis of rotation.
** The pointer shifted by just 6,000 milliarcseconds — the width of a human hair as seen from 10 miles away
* At the time, the gyroscopes were the most nearly spherical objects ever made.
~ size of ping pong balls, they are perfectly round to within forty atoms
- Scaled to the size of the Earth, the elevation of the entire surface would vary by no more than 12 feet
* Measured changes in gyroscope the equivalent to an angular separation the width of a human hair viewed from 32 kilometers (20 miles) away over a one-year period. [0.5 milliarcseconds (1.4×10−7 degrees)]
The Apollo astronauts left retro-reflector mirrors on the Moon, and laser ranging from Earth can now track their positions to millimeters. At that level of precision, the Moon’s motion in orbit has confirmed gravitomagnetism, the source of frame-dragging, to 0.15%, or 130 times better than GP-B.
Precision measurements of the Shapiro effect or gravitational time delay for light, most recently in 2002 by the Cassini space probe
Gravity – no uniform model for all scales
The laws of classical Newtonian physics remain accurate in predicting the behavior of the vast majority of large objects—of the order of the size of large molecules and bigger—at velocities much smaller than the velocity of light
-By Newtonian Standards Atoms can’t exist
-Newtonian physics says that electrons would fall out of orbit into the nuclues
-Electron Orbits in actuality can only exist as very specific points
-Heisenburg Uncertainty principle – can’t know location AND speed
-First conceptualized in 1783 by Henry Cavendish
-Infinite Density; Event Horizon [point of no return]
-Matter that is inferred to exist from gravitational effects on visible matter and background radiation, but is undetectable by emitted or scattered electromagnetic radiation
-Hypothetical form of energy that permeates all of space and tends to increase the rate of expansion of the universe
-Dark Matter/Dark Energy Estimates
-Some estimates state The Universe is made up of 23% Dark Matter; 72% Dark Energy; and Atoms a mere 4.6%
Additional Information :
SPACETIME: From the Greeks to Gravity Probe B
NASA : Gravity Probe B
Sky&Telescope : Gravity Probe B: Relatively Important?
PC Magazine : It Took More Than 50 Years, But NASA Proves That Einstein Was CorrectScientific American : Earth’s Mass and Motion Warps Spacetime as Einstein Said
engadget : NASA concludes Gravity Probe B space-time experiment
National Geographic : Einstein Theories Confirmed by NASA Gravity Probe
NASA Gravity Probe Confirms Two Einstein Theories
Wired : Floating Gyroscopes Vindicate Einstein
spaceRef : NASA’s Gravity Probe B Confirms Two Einstein Space-Time Theories
PCWorld:Experiment Confirms Space-Time Vortex Around Earth, Makes Our Heads Hurt
What’s 96 Percent of the Universe Made Of? Astronomers Don’t Know
YouTube | Lecture 1 | Modern Physics: Quantum Mechanics (Stanford)