Skip to main content

10 crucial physics theories

TEN CRUCIAL PHYSICS THEORIES

Falling objects of different sizes
accelerate at the same rate
Who: Galileo galilei
When: 1589
to disprove Aristotle’s theory of gravity, Galileo dropped two balls of different weights from the top of italy’s leaning tower of Pisa.


Everything is composed of atoms
Who: Leucippus and Democritus
When: 5th century bc
Atomism proposes that everything is composed of an infinite variety of indestructible, immutable ‘atoms’ that collide or link up to form clusters.


Atoms are composed of smaller particles Who: Joseph John thomson
When: 1897
By demonstrating that cathode rays are composed of negatively charged particles, thomson effectively found the electron – the first of the subatomic particles to be discovered.


Every event has a natural cause
Who: Thales
When: c 580BC
Greek philosopher thales attempted to explain natural phenomena without reference to mythology. He was among the first to try to identify a substance from which all things are composed (water, he thought)


Buoyant force equals displaced fluid weight
Who: archimedes
When: c 250BC
Archimedes’ principle states that: “Any object, wholly or partially immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object.”


Atoms of an element are identical in size and mass
Who: John Dalton
When: 1803
our modern concept of atoms is based on a lecture in which Dalton proposed that matter is made of indestructible atoms, and that all atoms of the same element are identical.


Energy can’t be created or destroyed
Who: Julius von Mayer
When: 1842
German scientist Julius von mayer established the law of the conservation of energy within a closed system (though it can be converted between different types – for example, between heat and kinetic).


Objects move at a constant velocity unless acted on by external force
Who: Isaac newton
When: 1687
newton’s three laws of motion, including this first law, form the foundation of classical mechanics as we now understand it.


Mass has an associated energy
Who: Albert einstein
When: 1905
Arising from his theory of special relativity, einstein’s most famous equation (e=mc2: energy equals mass times speed of light squared) shows that the mass of an object is a measure of its energy.


Hadrons are composed of quarks
Who: Murray Gell-Mann and George Zweig When: 1964
Hadrons (subatomic particles including neutrons and protons that comprise atoms) are themselves composed of smaller particles called quarks.
Labels:

Comments

Post a Comment

Popular posts from this blog

HOW DO STARS DIE?

Stars die because they exhaust their nuclear fuel. The events at the end of a star’s life depend on its mass. Really massive stars use up their hydrogen fuel quickly, but are hot enough to fuse heavier elements such as helium and carbon. Once there is no fuel left, the star collapses and the outer layers explode as a ‘supernova’. What’s left over after a supernova explosion is a ‘neutron star’ – the collapsed core of the star – or, if there’s sufficient mass, a black hole. Average-sized stars (up to about 1.4 times the mass of the Sun) will die less dramatically. As their hydrogen is used up, they swell to become red giants, fusing helium in their cores, before shedding their outer layers, often forming a ‘planetary nebula’. The star’s core remains as a ‘white dwarf’, which cools off over billions of years. The tiniest stars, known as ‘red dwarfs’, burn their nuclear fuel so slowly that they might live to be 100 billion years old – much older than the current age of the Universe....
Post a Comment
Read more

DOES HOLDING YOUR BREATH MAKE YOU STRONGER?

It won’t make you stronger in the sense of building muscle in your heart or diaphragm, but holding your breath while training for certain sports has been shown to improve the ability of your muscles to cope with short, intense exertions. This works by increasing the concentration of bicarbonate in the blood, which helps to neutralise the lactic acid produced during anaerobic exercise. For this technique to work, you need to exhale normally and hold your breath when your lungs are empty, rather than taking a big breath in and holding that. There are significant risks, though. A 2009 study found that free divers who regularly held their breath for several minutes had elevated levels of a protein called S100B in their blood, which is an indication of long-term brain damage.
Post a Comment
Read more

Do video games change the brain?

Do video games affect behaviour? Video games are likely able to affect the way we behave in a number of ways. For instance, there’s concern about whether violence in games makes young people more violent. It’s not uncommon for news outlets to blame games every time a crime happens, but how true is that claim? This is controversial even within the scientific community. Yes, exposure to violence seems to affect the brain, but studies have also found that we’re good at distinguishing between real and virtual violence, and aggressive behaviour is better explained by other, mainly socio-economic factors. Numerous studies about the effects of games on the brain had been published, but all that information had not been put together until now. How did you review the research?  We gathered all scientific articles to date and compared results. In total, we found 116 experiments, the first from the 1980s. Many compared regular video game players with people who had never played; other...
Post a Comment
Read more