Knockouts

Knockouts are, above all else, quick. But what happens when someone gets knocked out?

Your brain is sitting in cerebrospinal fluid with the skull forming a protective outer shell. When a blow lands the skull recoils, moving in the direction the punch/kick has forced the skull, and then back again. The skull does not move much more than this. The brain, however, is like a boat in a turbulent ocean at this point - constantly moving back and forth in the fluid. Every time the brain makes contact with one side of the skull, trauma ensues. Newton's 2nd law says force = (mass) X (acceleration). Therefore, the larger the force (i.e. the heavier and/or faster the blow) the more severe the trauma. When the trauma is severe, the brain sends misfiring electric signals throughout the body which essentially overload the nervous system and the body shuts down - i.e. you collapse.

The blow itself also offers a lesson in physics. When a punch or kick is delivered, a transfer of kinetic energy occurs. If, for example, you throw a punch, you gather energy from your base, and while swinging your torso and then your arm, transmit that energy from your feet through your hand and into the opponent.

This principle is found in all knockouts, delivered with a punch or kick.

What is Lightning?

To understand what lightning is we must first look at the water cycle which exploits 2 well-known phenomenon. Evaporation is the process of a liquid absorbing heat and changing to a vapor. Condensation is the process of vapor or gas losing heat and returning to liquid form. As vapor rises, it enters cooler and cooler areas in the atmosphere, losing heat in the process. When enough heat has dissipated, vapor becomes liquid. Snow/sleet occurs when the atmospheric temperature is below the freezing point, the vapor, in turn, freezing instead of liquefying.

During an electrical storm upper portions of clouds become positively charged and the lower portions become negatively charged, creating an electric field. The process of charge development is still unclear. As charge builds in the cloud, the lower portion of the cloud, which is negatively charged, repels all the earth's electrons deep into the earth's surface - so the ground itself acquires a positive charge.

Next, the electric field itself creates a conductive path for the negative cloud bottom to contact the positive ground. The conductive path occurs because the negative charge "wants" to travel towards a positive charge and become neutralized. Remember, right before lightning strikes, a tremendous amount of voltage has built up ... ~tens of thousands of volts per inch (compare to your house voltage which is ~230 V). Voltage is the energy per unit charge. Current is the ensuing flow of energy. Think of voltage as the cause, and current as the effect.

The electric field ionizes the surrounding air - that is, it separates the air into positive and negative charge just like the cloud. The air ionized, now the charge seeks various paths to reach the ground. Differences in levels of air ionization, dust, etc. makes some paths better then others. Also, if a cloud's lower portion is not straight, the ensuing lightning will branch out. All of the above is what creates "branch-like" lightning. Thus, it is incorrect to say lightning always follows the shortest path, as the shortest path may not be the most conductive. Note - lightning can strike between clouds as well if the charge is as polarized as it is when lightning strikes the earth. There is also lightning which occurs above clouds - that is, lightning that strikes upwards into the atmosphere!

When lightning strikes, current is passing from the clouds to the ground, eventually neutralizing the charged clouds and air. Lightning bolts, traveling at 186,000 mps, reach temperatures of ~55,000ºF vs. the sun's surface (9,800ºF). The lightning bolt's heat causes the surrounding air to expand rapidly and literally explode, resulting in a shock wave known as thunder.

Physics of Surfing

How do surfers ride big ocean waves?

1) Ocean waves are a form of mechanical waves. Mechanical waves are disturbances traveling through space and time which jump from one particle of the medium (in this case water) to another ... so mechanical waves move energy, not physical substance. Wind causes ocean waves travel along the surface of water. Slope and width of ocean bed and wind speed, duration, and size all effect ocean waves size.

2)OK, so now that we know what ocean waves are, how do you surf them? Newton's 1st law states that, minus an outside force, objects in motion (e.g. waves) stay in motion and objects at rest (e.g. surfboards) stay at rest. Newton's 3rd law states every action has an equal and opposite reaction. As waves rise, they reach a point where they cannot sustain themselves and begin to collapse. This point of collapse is known as the wave's "break". Surfers exploit the break, pushing down on the board as the wave pushes up on the board. The board does not sink because the ocean water is denser than the surfboard. Also, water surface tension (the force which allows water to stick together and form droplets instead of spread out) is very strong and helps push the board up. All that's left is for the surfer to maintain their center of gravity, much like one does when riding a bicycle.


Now that you know all that, see if this doesn't seem to defy wave physics.

The Physics Behind Hangtime

If an object falls at the same rate it rises, how can basketball players hang in the air? In fact, it is an illusion. Gravity is always pulling a body towards the earth, but gravity works in an "up-down" (Y) direction. When a basketball player jumps towards the basket, he is moving in both the Y plane, and the forward-backward (X) plane. While gravity is pulling him down in the Y plane, it is not affecting his motion in the X plane - allowing for the illusion of the player hanging in the air. If you watch a dunk in slow motion, you will notice that the player is actually falling when he dunks the ball.

The trick to hangtime, then, is to maximize both X and Y vectors - by jumping off the tip of your toe at a 45° angle.

Watch Clyde Drexler's unbelievable hangtime.

What is Dark Matter and Dark Energy?

In 1933, Fritz Zwicky averaged the mass of certain galaxies and obtained a value far greater than expected - he determined there was an unseen "dark matter" that allowed for the discrepancy. Dark Matter was determined to be a directly undetectable state of matter with powerful gravitational effects.

But in 1998 an even more shocking discovery revealed that despite this 'dark' matter pulling galaxies together, the universe itself was expanding ... and at an increasing speed. While dark matter was keeping everything together, a stronger force was pushing everything apart! Moreover, galaxies were not being stretched ... instead, more space was being created. The same amount of acceleration of this expansion was observed irrespective of position.

This means that "dark energy" is uniform and also much stronger than dark matter.

It doesn't stop there ... the visible matter, as immense as it is, comprises only 4% of all the matter in the universe - dark matter is believed to take up 21% of the pie, with dark energy taking up an unbelievable 75% of distribution in the universe!

Here's an easy to understand documentary explaining the phenomenon.

Fight Science: Ninja Strike

Ninja's are known for stealth attacks and an advanced weaponry skill set. Their strikes (both punches and kicks) are not as powerful as other martial arts strikes, but they are equally devastating.

For example, a strike to the axillary nerve (found on near the armpit) causes erratic electric signal firing. Pain aside, the punch causes a circuit overload, and the body cannot cope with the electrical impulses being sent throughout it. Along with a flood of calcium and potassium, the body shuts down.

The most famous ninja strike is probably to the vagus nerve (found above the jugular vein). Connected to the brain and heart, a strike to the vagus nerve causes erratic electrical discharges which the brain interprets as stress on the heart. In response, the brain slows heartbeat. Translation: the opponent collapses.

Ribbit Ribbit

Why do frogs make that noise?? First off, every species has its own call. While unique to each species, every male frog primarily uses it to attract a mate. Females return the call to communicate with the male. Calls can also indicate an ensuing rainstorm, or to defend one's territory.


Listen to some of the various calls.

What is Eye Color?

It may be man's most attention-grabbing quality, but what really is eye color?

In short, eye color is the expression of a combined number of genes. Eye color expression is like screwing in a certain color light bulb to emit a certain color of light. If you replace the bulb with a bulb of another color, the emitted light's color will change.

Eye color is not a blend of the parents' colors. Each parent has two pairs of genes on each chromosome, all of which can effect the ultimate color expression in a myriad of ways. Brown eye color is the dominant gene, needing only one copy to be expressed, while blue (recessive) requires both copy's. However, no one gene controls eye color - the OCA2 gene, controlling the amount of melanin pigment produced, accounts for ~74% of variation in eye color. Other genes effect the OCA2 gene's expression.

Geneticist Dr Rick Sturm states, "We believe ... there are two major genes - one that controls for brown or blue, and one that controls for green or hazel - and others that modify this trait". This means that brown-eyed parents can have a blue-eyed child, and vice versa.

Sonic Boom

If you've played Street Fighter, you know that Guile created sonic boom's to attack an opponent.

In real life, aircrafts, and humans, can in fact break the sound barrier.

Breaking the sound barrier not only creates an audible effect, known as a 'sonic boom', but also a visible effect, seen in the picture above. When an aircraft is moving through the sky, it is pushing air out of the way (creating pressure waves) much like a boat which causes ripples in the water as it moves.

When moving at, and then exceeding, the speed of sound, the pressure waves the aircraft creates compress into one huge shock wave because the air cannot move out of the way of the aircraft fast enough. Since air always has tiny droplets of water floating around, breaking the sound barrier creates a compressed cone of water vapor. That is, during a sonic boom, you can actually see the effects of sound!

It is theorized that certain dinosaurs, by whipping their massive tails, could also break the sound barrier.

I mentioned in the beginning that humans can also break the sound barrier. It is true. Whenever one cracks a whip, you are causing the end of the whip to move faster than the speed of sound, thus creating a 'cracking' noise.

Here's a video of a plane breaking the sound barrier. And one more.

Density and Sound

Ever wonder why your voice sounds lighter when inhaling helium? It is because sound waves speed is dependent upon the medium through which it is moving.

Through 'air' at sea level, sound moves at ~770 mph. When you change the density of the medium, the sound wave will most faster or slower.

Helium is ~6 times less dense than air; i.e. sound will move 6 times faster through it, translating to a higher pitch.

In contrast, something like sulfur hexafluoride is ~6 times denser than air and the exact opposite effect will happen.

See for yourself.