how does threading water keeps you afloat?
437363
lift vs drag which is basically the same principle as flight, but in the water it's called hydrodynamics.  the body is naturally buoyant, but the propulsion created by sculling/kicking forces the body to move in different directions.  for treading, that direction is toward the surface.
1132679
Maybe it has something to do with the actions you're making.  When you're timing yourself out of water, you're just sitting there right?  But when your under water, you're treding or moving in some sort?  Try timing yourself when your walking around the house or jumping up and down....the blood takes in more oxygen(which means you need more) when its pumping faster.  Just an idea!
1064956
Quicksand is tiny round granuals of sand suspended in water bring forced up from below.  When you try to pull your leg out, it just pulls you in lower.  The key is to lie down, float to the top and roll off.
3296
Quoted:\n\nVortex flows show the sensitivity of water to external forces. The speed of movement of water in a vortex has a rhythm of its own; it extends and contracts in a rhythmic pulsation. The vortex is really composed of a series of flowing surfaces (like the ropes) all binding together as if by an invisible hand.\n\nThese flowing surfaces move at different speeds, slow on the outside and fast on the inside. The speed of movement of water in a vortex multiplied by the radius from the center is a constant. This means that forces in a perfect vortex approach infinity the hydrogen bonds of the water molecule cannot sustain the pressure difference and begin to stretch and weaken releasing powerful forces.\n\n....continued....\nWhen structured waters are made properly they are of immense benefit. Research has led to a number of other exciting discoveries relating to the benefits of structured waters upon the living system. These waters act as mineral carriers and more efficient nutrient transporters. Preliminary tests with cut flowers and other plants have shown a 400% increase in water and nutrient uptake when watered with structured water as opposed to the control group, which was watered with distilled water. What is true for plants may as well be true for animals. Preliminary experiments with vitamins and herbal extracts show a definite increase in absorption. Riboflavin, vitamin B12 is an easy vitamin to measure in urine. Testing with riboflavin has shown an increased absorption of 500% when taken with colloidal water versus distilled water.\n\nPlease refer to the site listed below:
1079627
If you are talking about regular speedo's.. the idea is that if you dont have fabric hanging out, you'll reduce your drag.. counter example.. a drag suit.. loose suit, more drag\n\nIf you are talkin about a Fast skin ( the tights, or full body ) they are designed to compress your muscles to optimize their performance.. dont ask me why it works.. but I know that when your muscles are compressed they lose less energy to vibration and last longer. but still they also make them tight so youre not dragging fabric around
291004
if an object is floating, the buoyant force on it equals its weight -- the vertical forces have to sum to zero.  try drawing a free body diagram to convince yourself of this.
202226
a great place to start would be in your toliet.....chit floats so you wouldnt ever have to worry about drowning!
638426
you are naturally bouyant, fill your lungs with air as much as you can, and you will float... just dont panic when a wave hits your face
104409
This is a classic problem from hydrodynamics textbooks. The short answer is, it is approximately simple harmonic motion. You can compute the restoring force caused by the displacement of the liquid if you depress a floating boat (Archimedes principle) and that then, balanced with the weight of the boat, creates the conditions for simple harmonic motion. You can approximate the period and amplitude of motion etc. \n\nHowever it gets more complicated than this of course:\n\na. There are damping forces caused by the motion of the boat through the water and the air\n\nb. The water is not completely incompressible, and the density of the water varies some with depth (a tiny effect)\n\nc. There are surface tension effects and entrainment effects\n\nd. The motion of the boat will be more complicated than simple linear motion in one dimension\n\ne. There will probably be deformation effects on the boat, changing its shape\n\nf. gravity is not constant as the boat is moving up and down a small distance in a gravity gradient\n\nand so on. \n\nHowever, the REASON that sines and cosines are so prevalent everywhere in physics is because simple harmonic motion is such a good approximation for so many things. \n\nWhy is this?\n\nWell consider Newton's Second law: F=ma, where F is force, m is mass and a is acceleration. Newton's second law is not always true, in the quantum world and in relativistic situations, but it is true under many conditions, so it is a good place to start. \n\nIn general, the force F will be some sort of nonlinear function of position x:\n\nF=F(x)\n\nHowever, if x is small, then we can approximate F(x) by a McLaurin series:\n\nF ~ F(0) + x F'(0) + h.o.t. \n\n(h.o.t. is a common acronym for higher order terms).\n\nThis then produces the equation for simple harmonic motion, when substituted into Newton's 2nd law:\n\nF(0) + xF'(0) = m d/dt(d/dt(x))\n\nMany other equations in physics like Schrodinger's equation, or wave equations with forcing, or the heat equation, or the inhomogeneous Laplace's equation include 2nd order derivatives, and can similarly be put in some form where simple harmonic motion is the result. So as strange as it seems when you are just learning about SHM in physics, it really is everywhere in all kinds of unexpected places! \n\n\nOne of my favorites is the waves of heat and cold that are travelling down into the earth from the seasonal forcing produced at the surface. Drilling down, one can observe these waves of hot and cold (with some diffusion) going back many years.
230342
Hold your leg under a firm stream of very cold water because the water is cold your blood vessels wil open and allow enough blood to your legs.
460879
What your actually thinking of are baffles. These cause the water to travel in a zig zag way or even perpendicular to flow direction. This slows the water by taking its Kinetic Energy and so reduces wear on other structures or machinery
599546
water always follow the less resistance route...
492027
Without a lifejacket, the boater will still most likely continue breathing, even if unconscience.  The body is trying to sink, but lungs filled with air will keep the body afloat.  If the person breathes in and his or her lungs fill with water, the person will definitely sink. However, after drowning, the gases in the blood stream accumulate, allowing the dead body to rise to the surface of the water.
648278
a tab floats and stops the water
447637
Underwater basketweaving
429917
A lot more than most exercise. Swimming requires you to be able to balance yourself in a certain position while in the water. In order to balance your body utilizes a lot of small, core muscles in your midsection to keep balanced. Other than these small muscles, your forward propulsion is generated from your upper body and your legs also help with balance and propulsion. In other words, your whole body.
191138
The fibers form small cells which the water can fill. Wetting (a form of adhesion) of the fibers and surface tension (on water surfaces not contacting the fiber) tend to hold the water in the cells.