Crash Course Physics has just put out an episode on fluids at rest (a.k.a. hydrostatics). For those who are unfamiliar, Crash Course is an educational YouTube channel that offers fun, instructional videos on a large and ever-growing array of topics. In this video, they tackle a lot of important basics for fluids, including the principles behind hydraulics, how to measure pressure, and how buoyancy works. It’s pretty densely packed, and, if you’re learning the concepts for the first time, you’ll probably pause and rewatch some segments, but even if you’re familiar with the topics, it’s a nice refresher. (Video credit: Crash Course Physics)


Pluto (bottom image) with various other non-planets.

Since everyone has their knickers in a knot over Pluto not being a planet, here are various different celestial objects who are also not classified as planets. You’ll notice, just because it’s not called a “planet” doesn’t mean it isn’t cool.

Let us be reminded, there is no heirarchy of celestial bodies. It wasn’t necessarily “demoted” from planethood, it was simply reclassified as something else. There’s literally no reason to be emotionally attatched to the idea of Pluto’s planetary classifaction.

But what “classifies” a planet anyway?

According to the International Astronomical Union, there are 3 basic requirements that it must meet:
1) It orbits the sun
2) Sufficient mass to assume a “hydrostatic equilibrium” (meaning it’s mostly shaped like a globe)
3) Has “cleared its neighborhood” in its orbit.

The third one is where Pluto fails. What they mean by “clearing the neighborhood” is that the orbital path is good and clear. Every planet will still collide with something now and then but their orbital paths are not occupied by anything that is similar to the size of the planet itself. They’re not really in danger of running into much of anything except maybe an asteroid or a comet that might enter their path and collide.

In addition, here is an image showcasing the dwarf planets of the solar system. Pluto isn’t alone in it’s classification.

So don’t be sad over Pluto not being a planet, you’re just being melodramatic. Wipe your tears away with some scientific literacy. ;)


Hydrostatic Drive Panzer IV.

This was the only one ever made. It was captured by the USA & taken back to Aberdeen Proving Ground for testing.

It was tested briefly but due to a breakdown & lack of spare parts all testing was halted & it was put on display.

Hydrostatic drive is very simple. In a traditional panzer IV you would have a transmission that would deliver power to the two front drive units.

In this prototype the transmission has been eliminated & replaced with a heavy duty high pressure hydraulic pump that is placed behind the engine. 

The two rear idler wheels have been replaced with two hydrostatic drive units. The sprockets in the front are now the idler wheels.

So here is how it all works. The main engine powers the pump that feeds the two drive pumps. The driver has a half moon shaped steering wheel (like in the Tiger) instead of the two tiller levers that a traditional Panzer IV had. This would control a series of valves that would increase or decrease power to the drive units. So if you wanted to turn left you turned the wheel to the left & that would increase pressure to the right drive unit & lower pressure to the left unit. Its that simple. Its the same principal for forward a reverse motion. The accelerator pedal would increase or decrease pressure to the drive units as the engine rpm changed…so simple.

This was way ahead of its time & would have made a very interesting production model.

*slams hands on table*

A hydrostatic skeletal system

Hydroskeleton. This thing.

That’s it, that’s exactly what I’ve been describing in awkward roundabout terms for years when referring to Danny Phantom-style ghosts. 

Ghosts use a hydrostatic exoskeletal system… and actually dude I think the cross fibers as opposed to the traditional helical model actually makes more sense considering most of them tend to be solid (yet capable of shifting and warping their shape).

This is exactly why I watch TED talks about genitalia at two in the morning. Learning esoteric details about science and reality is never wasted, my friends, especially when you’re a writer.


In the 17th century, scientist Robert Boyle proposed a perpetual motion machine consisting of a self-filling flask. The concept was that capillary action, which creates the meniscus of liquid seen in containers and is responsible for the flow of water from a tree’s roots upward against gravity, would allow the thin side of the flask to draw fluid up and refill the cup side. In reality, this is not possible because surface tension will hold it in a droplet at the end of the tube rather than letting it fall. In the video above, the hydrostatic equation is used to suggest that the device works with carbonated beverages (it doesn’t; the video’s apparatus has a hidden pump) because the weight of the liquid is much greater than that of the foam. Of course, the hydrostatic equation doesn’t apply to a flowing liquid! The closest one can come to the hypothetical perpetual fluid motion suggested by Boyle is the superfluid fountain, which flows without viscosity and can continue indefinitely so long as the superfluid state is maintained. (Video credit: Visual Education Project; submission by zible)


Weekend House in Downtown São Paulo, Brazil by SPBR | via

Clouds, drizzle, rain, snow or hail, in all its physical states water is related to sky.

However, if we are requested to think about a [swimming] pool, our imagination automatically starts to dig into the ground. Seas, lakes, and ponds explain the reason we react in that direction: essentially, a pool fells like a piece of a lake. It makes sense, the image corresponds to the word, water that rests smoothly on the ground. Water defines the surface.

But if I mention a specific type of pool, a water tank or a water tower, we first imagine an elevated volume of water, a pool detached from the ground level. In this case, hydrostatic pressure is a requirement to fulfill pipes, to supply water. Water level holds a potential possibility.

While walking on the ground,we could ask: where is the surface? In the specific sense of the word, surface has no layers or thickness. However, if one walks in a city like São Paulo [or New York], the ground level does not correspond to the surface anymore. There are some pieces of the ground that haven’t been touched by the sunlight for decades since buildings have permanently shaded them.

Photography: Nelson Kon

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Star Wars Meme: [½] Planets


“An idyllic world close to the border of the Outer Rim Territories, Naboo is inhabited by peaceful humans known as the Naboo, and an indigenous species of intelligent amphibians called the Gungans. Naboo’s surface consists of swampy lakes, rolling plains and green hills. Its population centers are beautiful – Naboo’s river cities are filled with classical architecture and greenery, while the underwater Gungan settlements are a beautiful display of exotic hydrostatic bubble technology.”
—from the star wars databank 

On August 24th, 2006, the International Astronomical Union (IAU) officially defined what constitutes a planet. For a celestial body in our solar system to be defined as a planet, it must:

1. Be in orbit of the Sun
2. Have sufficient mass to assume a nearly round shape (officially known as hydrostatic equilibrium)
3. “Clear the neighborhood” around its orbit

This designation meant that Pluto – first discovered in 1930 by Clyde W. Tombaugh – was no different than any of the other 70,000 icy objects that comprise the Kuiper Belt, a region that extends from the orbit of Neptune out to 55 astronomical units (55 times the distance of the Earth to the Sun).

After decades of observation, astronomers have continued to discover other large Kuiper Belt objects, such as Eris in 2005, which was determined to be larger than Pluto itself. The discovery of Eris – which has approximately 25% more mass than Pluto – posed an interesting question to the scientific community: would this object be the 10th planet in our solar system? 

“If Neptune were analogized with a Chevy Impala in mass, then how big is Pluto compared to that? Pluto would be a matchbox car sitting on the curb.” - Neil deGrasse Tyson

Based upon the IAU’s definition above, any object that doesn’t meet the third criteria is classified as a dwarf planet – including Pluto, Eris, and many of the other objects located in the distant reaches of the Kuiper Belt. In spite of this new designation, Pluto still holds a special spot in the hearts of scientists and astronomers, as NASA has sent their New Horizons spacecraft to observe it closely. Slated to arrive in 2015, New Horizons will capture the first close-up images of Pluto’s surface.

Image Credit: PBS

1. Pluto and the Developing Landscape of Our Solar System
2. Why Pluto is No Longer a Planet

New type of cell movement discovered

In a new study from the University of Pennsylvania and National Institute of Dental and Craniofacial Research, scientists used an innovative technique to study how cells move in a three-dimensional matrix, similar to the structure of certain tissues, such as the skin. They discovered an entirely new type of cell movement whereby the nucleus helps propel cells through the matrix like a piston in an engine, generating pressure that thrusts the cell’s plasma membrane forward.

“Our work elucidated a highly intriguing question: how cells move when they are in the complex and physiologically relevant environment of a 3-D extracellular matrix,” said Hyun (Michel) Koo, a professor in the Department of Orthodontics at Penn’s School of Dental Medicine. “We discovered that the nucleus can act as a piston that physically compartmentalizes the cell cytoplasm and increases the hydrostatic pressure driving the cell motility within a 3-D matrix.”

R. J. Petrie, H. Koo, K. M. Yamada. Generation of compartmentalized pressure by a nuclear piston governs cell motility in a 3D matrix. Science, 2014; 345 (6200): 1062 DOI: 10.1126/science.1256965

Penn and NIH researchers measured the internal pressure of individual fibroblast cells (in orange) moving through a three-dimensional matrix (in blue). They found that, in this environment, the cells’ nuclei operate like an engine’s piston to push the cell forward.  Credit: University of Pennsylvania/NIDCR


 Reader elimik asks: 

Why do modern submarines have round bows instead of pointy ones, like the early WWII ones?  

Interestingly, there are more factors that affect this design choice than I originally thought! Perhaps the biggest factor, though, is propulsion. Although early submarines ran through several forms of propulsion from human power to steam, by World War II many subs were driven by diesel-power on the surface and relied on battery power when submerged. Power limitations meant that submarines of that era did most of their travel while at the surface, not underwater. As a result, the ships had better control and decreased drag with a pointed bow similar to that of a surface ship. It wasn’t until the advent of the nuclear-powered submarine that it became practical for submarines to spend most of their time submerged. Once fully-underwater travel was feasible (and, indeed, preferable), many subs transitioned to a blunter, rounded bow that’s more hydrodynamic underwater–and simultaneously more problematic control-wise when moving on the surface.  

Another factor separating WW-era submarines and modern subs is the depth to which they submerge. The deeper a submarine dives, the greater the pressure it must withstand. Rounded or cylindrical shapes make much better pressure vessels because they distribute pressure evenly around a surface. Historically, many subs have balanced control and hydrodynamics against pressure requirements by having two hulls, an outer one for cutting through surface waters and an inner cylindrical one that bears the brunt of the hydrostatic pressure. As we developed stronger materials, though, submarines have achieved greater depths. The German Type VII submarine, the most common U-boat of WWII, had a test depth of 230 m, whereas today’s Los-Angeles-class U.S. submarine can operate at 290 m. (Each 10 meters of depth adds about one atmosphere’s worth of pressure.) The combination of nuclear power for subsurface propulsion and stronger materials that allow deeper dives enables many modern submarines to have a single hull–the rounded hydrodynamic and pressure-resistant bow we commonly see.  (Image credits: U534 by P. Adams and USS George Washington by U.S. Navy)


Despite the strange shapes of the arms on this container, the fluid inside will always settle to a common height. This is because each interconnected section is open to the outside air. The fluid’s surface has to reach a static equilibrium with the atmosphere–i.e. the surface of the fluid must be at atmospheric pressure–and the pressure at the lowest level in each section must match because the arms are connected. When fluid is added, the height of the columns oscillates some because the momentum of the added fluid carries the column past its equilibrium position, much like a perturbed mass hanging from a spring will oscillate before settling.


Throwback Thursday: What’s The Farthest Object We’ve Ever Seen In Our Solar System?

“But Sedna will rule them all. Not only is it the largest Oort cloud object known, but it’s likely (we aren’t sure) in hydrostatic equilibrium, meaning that if it is, it will become the first dwarf planet beyond the Kuiper belt.Perhaps best of all, Sedna will someday (soon!) pass all the other presently known Oort cloud objects, reaching a maximal distance from the Sun of 936 A.U., or 1.5% of a light year from our Sun. So embrace the farthest objects in our Solar System, and know that the Oort cloud likely has even more surprises in store for us; we’re only just beginning to understand it!”

In our Solar System, we have the inner, rocky worlds, an asteroid belt, the gas giants and then the Kuiper belt. Out beyond that, in theory, we have the Oort cloud, where a few of the longest-period comets come from.

Due to its tremendous distance – the Kuiper belt ends at just 50 A.U. – we weren’t able to find Oort cloud objects in situ for all of the 20th century. But that changed with the discovery of Sedna, and now we’ve got a handful of others, indicating to us at last that the Oort cloud is real!


Folds in rocks in Crete, Greece

A geological fold occurs when one or a stack of originally flat and planar surfaces, such as sedimentary strata, are bent or curved as a result of permanent deformation. Synsedimentary folds are those due to slumping of sedimentary material before it is lithified. Folds in rocks vary in size from microscopic crinkles to mountain-sized folds. They occur singly as isolated folds and in extensive fold trains of different sizes, on a variety of scales.

Folds form under varied conditions of stress, hydrostatic pressure, pore pressure, and temperature gradient, as evidenced by their presence in soft sediments, the full spectrum of metamorphic rocks, and even as primary flow structures in some igneous rocks. A set of folds distributed on a regional scale constitutes a fold belt, a common feature of orogenic zones. Folds are commonly formed by shortening of existing layers, but may also be formed as a result of displacement on a non-planar fault (fault bend fold), at the tip of a propagating fault (fault propagation fold), by differential compaction or due to the effects of a high-level igneous intrusion e.g. above a laccolith.


The Mexican burrowing toad has a number of features that distinguish it from other frogs and toads.  Aside from it bizarre purple and orange-spotted skin, this frog’s tongue is attached at the rear of its mouth, and can change shape dramatically.  When the tongue is at rest, it lays in a flat triangle, but when the frog is hunting, hydrostatic pressure turns the tongue into a hard rod that projects through a groove in the frog’s lower jaw.  In addition, the Mexican burrowing toad is the only amphibian that uses both its eyelids to close its eyes.

MY SOLAR SYSTEM DON’T, MY SOLAR SYSTEM DON’T, MY SOLAR SYSTEM DON’T WANT NONE UNLESS YOU 1. are in orbit around the Sun. 2. Have sufficient mass to assume hydrostatic equilibrium (a nearly round shape) and 3. Have “cleared the neighborhood” around your orbit. Sadly, Pluto doesn’t cover the last one too well. Never forget Pluto in this funny planetary definition Pluto print that should help in the never ending debate planetary status of the tiny infamous ice rock planet, Pluto.

Inktober day 6
“Rumor has it that Sakura’s ultra rare Subaru 22B chassis was a museum relic found amongst the ruins of the old factory leveled in the Gunma Prefecture quake of ‘38. Partially crushed, she had to do quite a bit of metalwork to restore the cabin. Once done she packed it to the gills with Tanaka Gen II wheel motors, torque vectoring hydrostatic overdrive, and a twin module direct methanol fuel cell. She has the only car in the crew to come close to keeping up with Fumiko’s R33.
#inktober2016 #inktober #damon moran #telodyne #damon Moran art #stancenation #sketching #drawing #inking #futuristic #scifi #drift #cars #streetracing #subaru #22bsti #stance #stanced #stancenation #jdm #tuner #electric #fuelcell #iamthespeedhunter #speedhunters #superstreet #importtuner #tokyodrift #anime #animation #wrx #sti

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Spirula spirula internal shell | ©Ricardo in PR

A delicate spiral internal shell of the cephalopod Spirula spirula, found in the beach of Guajataca, Puerto Rico.

Spirula spirula is a species of deep water squid-like cephalopod mollusk. Because of the shape of its internal shell, it is commonly known as the Ram’s horn squid or the Little post horn squid. Since the live animal has a light-emitting organ, it is also sometimes known as the Tail-light squid.

Live specimens of this cephalopod are very rarely seen, because it is a deep-ocean dweller. The small internal shell of the species is however quite a familiar object to many beachcombers [1].

The shell of S. spirula in entirely enclosed in the mantle. It is divided into approximately 25 to 37 chambers connected by a siphuncle. This shell serves as a hydrostatic system, allowing and animal to control its buoyancy. The shell is located in the posterior half of the mantle, and its buoyancy pattern results in a characteristic “head down” positioning often observed in Spirula [2].

The distribution of Spirula spirula is poorly known. These mollusks are generally found in tropical waters, including the waters off the coasts of Indonesia, New Zealand, south Africa, northwestern Africa, the Canary Islands, and in the Gulf of Mexico.

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