learn tech

How were the pyramids built?

The pyramids from Egypt were build using workers that were paid for their labor. They would use a giant sled to carry the lime rocks to the place where the pyramids would be built. The workers would pour water in front of the sleds to make them slide smoother on the sand.

Also, the big lime rocks were cut by using water, some abrasive material and a copper saw. The rocks were pushed up a ramp that would be built on the lower levels of the pyramids. It was better this way as the alternative, building a straight ramp that goes to the top of the pyramids, would require more material than the pyramid itself.

The Gizeh pyramid is 140 meters tall, it took 2 million stones to build it and each such stone has 130 tons. It took 20 – 30 years to make such a pyramid, but they were and even today could be a spectacular view if they would still have their white limestone cover and the golden tip.

geek science

13 misconceptions about global warming

Derek Muller tells us about 13 misconceptions about global warming. Since climate change is a big subject to speak of and it is hard to understand, it may suffice to say that the way our industries worked in the last 200 years have put a great toll on our atmosphere, namely we have spewed out a lot of CO2 and other toxic gases in the air.

This will lead to the atmosphere trapping more and more heat in the air, which leads to more ice melting from the polar areas. Then that leads to floods, a ton of habitats being destroyed, and many species being endangered. Global warming could also lead to more clouds in the sky which may block much of the sun light, which, in turn, can lead to cooler temperatures than we’d expect.

Usually the changes would not be that big to destroy humanity, but they would be enough to change the geographic landscape in many areas due to flooding and it would be dangerous for many species of animals. We need to care for those too.

geek learn science

Climate change is boring

As with anything science, the scientists don’t really know how to frame their findings and the dangers we may face. They need science communicators like Derek Muller, from Veritasium, who can explain in plain words what is happening and why we should care about what scientists are telling us. It is a well known fact that the general climate will change and while +1-2 degrees Celsius overall might not sound big, it can wreak havok in many parts of the world.

We should stress one thing out: Earth, as a planet will be just fine. We’re just nothing compared to it, but if we let our civilization affect climate change in such abrupt ways, then many animal species and our selves will be hurt by these actions of ours.

Climate change movement triggered the alarm that we should be more green, more careful with our home and it is a bad sign that Australia doesn’t regulate the companies in regards to carbon emissions like they did. We need to keep a price on carbon.

The cause of concern is that our actions, like burning fossil fuels, generate a lot of carbon that then is spewed into the atmosphere. That carbon will then trap the heat that comes from the Sun and Earth and irradiate it back to Earth. This leads to increasing temperatures but, also surprisingly, it can lead to small glaciations.

learn science

Veritasium explains the 5 fun physics experiments

Recently Veritasium presented this video with 5 fun physics experiments and asked us to explain them. Now he explains then in the video from above.

1. Cereals will stick to a magnet. This is not because cereals have iron atoms in them.

2. If you put any small objects over water they will follow a magnet.

It is because the water is a diamagnetic molecule and in the presence of a magnet behaves like a small magnet that repels your magnet. Thus it will create a small hole in the water and the objects will fall in it.

3. The center of mass of a stick or cane can be found just by moving your fingers under it until you get them close together.

This is because the finger closer to the center of mass carries more of the stick’s mass and thus the friction force is bigger in there. When the other finger closes in on the center of mass it will experience the same friction force as the former finger and both fingers will be able to move together.

4. Flipping the phone end over end there is not way to do it without making it also spin in other axis too. This happens because the intermediate axis is between the longest and shortest axis that have the most or the least inertia. due to this intermediate state the phone will never be able to spin only o that intermediate axis.

5. An electrically charged object can deflect a stream o water.

This is due to the fact that the water has ions, negative ions HO- and positive H+ and when you get close with an electrically (-) charged cup, the negative ions are moving back into the tap and the positive ones attact the water stream to the cup.

learn science

Veritasium: the information that makes the diffrence between me and you can be stored on a floppy-disk

We, humans, share almost all the genetic code with every other human being on this planet. The total information in the DNA that makes us, well US, can be stored on a floppy-disk, in about 1.5MB of information. That is the amount of information that is DIFFERENT from human to human. The total information contained in the DNA is about 1.5 GB.

Can you imagine? 1.5 Gb of information in a 2 meter long strand of acid (that what the DNA is) that si trapped inside a cell’s nucleus.

From 100 000 genes that could be located in the DNA it seems that only about 19 000 are protein generating genes, but that is a story for other times.

In any case, in regards to information, even though some languages make you speak very quickly, the same quantity of information is sent to the listeners in the same time in any language. The total information in all our cells amounts to about 60 zettabytes meaning more than all the information that the humanity will create until 2020.

geek learn science

Misconceptions about the Universe? Well, learn that it is expanding at more than the speed of light

The Universe is expanding at more than the speed of light. In the near vicinity of us, up to 1 megaparsec, the space is expanding with about 70km/s, but at 2 megaparsecs, at 140km/s and so on. After a certain distance, the space is expanding as a rate faster than the speed of light. The Universe has been expanding faster that the speed of light since the Big Bang or everywhere stretch.

Thanks, Veritasium, for reminding us that we won’t reach some of the galaxies ever-never-ever 😛 Now, we cannot move through space faster than the speed of light, but that won’t stop space from expanding at more than the speed of light. In a certain way some galaxies are travelling farther away from us at more the speed of light right now. Ooops.

The Hubble sphere is the area beyond which everything is moving away from us faster than the speed of light. Just learned something new 😀

learn science

Faster than light? Veritasium explains why such contraption is not possible now

Veritasium explains why we cannot have now a contraption, a device, that is going to have the speed of light: because we do not have such freaking big amounts of energy, that is why.

If you were to have a stick long enough to reach the Moon and would move it fast over the Moon’s surface so that it may appear that the tip of the stick is moving faster than the speed of light, then that would not be possible. Why? Because the fastest a force can move through the stick from your hand to the tip of it is the speed of sound in that stick (remember the slinky experiment).


But if you were to have a rotating satellite that rotates at over 10000 rpm and has two long arms of 285 km each, then the tips of those arms wouldn’t have the speed of light? Nope. Because of the relation between the centripetal force and the arms speed. The centripetal acceleration is ac = v^2/r , v is the speed and r is the radius. The centripetal force would be Fc = m *v^2/r. Now, if v = c, the speed of light, then Fc = E/r, and for a 1kg object the force needed would be 300 GN or 67.4 Giga-pounds of force (4.448 newtons are in a pound).

That is a a lot. An elephant has 50kN force (gravity) so you would need a force equal to 6 million elephants to do that job. But there is more: Derek calculated that at 30 m from the center of rotation, the arm would need to have a base as big as the observable universe in order to support that kind of force. And there is the inertia we need to fight when we need to accelerate the arm from one speed to another so the arm, the tether, would have to be thicker. If you are at 99% the speed of light and you want to accelerate the arm to 100% the speed of light, then you would need an infinite amount of energy.

Lastly, the arm is kept together by the electromagnetic force so the particles from within cannot communicate with each other faster than the speed of light. Since the particles communicate using electromagnetic waves ie light ie photons, the maximum speed in those arms is the speed of light (and of course the force will only be transmitted as fast as the speed of sound in it, see above). So, nope. Nothing can go faster than the speed of light.


learn on the web

Veritasium: how Facebook is ripping us off

It is a known thing that Facebook pushes the envelope by asking individual account holders to promote their personal statuses in order to gain more visibility. The issue is more poignant if you are a Facebook page admin.

Here Derek Mueller, from Veritasium, explains how Facebook takes your money to bring you more likes, likes of which many are fake, and then hides some of your content in order to make you buy more likes.

It seems that Facebook is not hiring click farms, but instead guys from click farms simply clickthrough and like many pages in order to hide their false likes under a rain of seemingly natural likes.

Facebook knows this, but it won’t let you delete/block such fans in bulk. In return you get many fans, low engagement and even lower exposure. Well done, Facebook!

geek learn on the web

Does alien life exist?

Veritasium answers an age old question: are we alone? The answer is that we cannot say definitively that there are not, since there could be about 38 billion Earth like planets in our galaxy. The study of exoplanets revealed that each star might have at least one planet and one in six such planets might be a planet just like Earth in size and orbit distance, with liquid water on its surface.

Once we’re mastered space travel we’ll be in for a whooping ride. I guess there could be some sort of dinosaurs out there t, too. Imagination flows wildly 😀

entertainment learn

Our mass is not from the Higgs Boson

Veritasium explains hwy the mass out our body is not generated by the Higgs Boson. The electrons wieght up to 21 grams in our body and the quarks that are contained in the protons and neutrons or the nuclei add up to 1% of out mass.

Where from comes the rest? It comes from the energy these quarks generate when they are bound together (strong force). E=mc2 explains why the energy can amount to the mass we see around us. so, our mass is a result of the energy form the atomic nuclei.