άλμπερτ αϊνστάιν

Δημοσιεύτηκε στις 6 Ιαν 2015

View full lesson here: http://ed.ted.com/lessons/einstein-s-...

As the year 1905 began, Albert Einstein faced life as a “failed” academic. Yet within the next twelve months, he would publish four extraordinary papers, each on a different topic, that were destined to radically transform our understanding of the universe. Larry Lagerstrom details these four groundbreaking papers.

Lesson by Larry Lagerstrom, animation by Oxbow Creative.

η φυσική και η κιθάρα

Guitar masters like Jimi Hendrix are capable of bending the physics of waves to their wills, plucking melody from inspiration and vibration. But how do wood, metal, and plastic translate into rhythm, melody, and music? Oscar Fernando Perez details the physics of playing the guitar, from first pluck to that final shredding chord. 

Lesson by Oscar Fernando Perez , animation by Chris Boyle.

μοντέλο κλίμακας του πλανητικού συστήματος με πλήρεις τροχιές πλανητών

Στον στεγνό πυθμένα μιας λίμνης στη Νεβάδα, μια ομάδα φίλων δημιουργεί το πρώτο μοντέλο κλίμακας του πλανητικού συστήματος με πλήρεις τροχιές πλανητών: μια πραγματική απεικόνιση της θέσεώς μας στο σύμπαν.

Μια ταινία των Wylie Overstreet και Alex Gorosh, 2015

alexgorosh.com

wylieoverstreet.com

μονοδιάστατη κίνηση

The mysteries which lie beyond the clouds

have intrigued us since the dawn of mankind.

Scientific advances that seemed incomprehensible for ancestors

are becoming our new reality.

Innovative companies, like SpaceX, help make space exploration

easier and more affordable.

Physics is critical to their continued progress.

Pressing beyond earth's atmosphere, as well as providing a safe return,

requires a clear understanding of one dimensional kinematics,

which tracks position, velocity, and acceleration as a function of time.

The rocket's successful mission can be described

with one dimensional kinematics.

As the rocket takes off, it accelerates upward increasing both

its vertical velocity and position.

At the top of its trajectory, it hovers, briefly stationary.

The rocket returns to earth in a controlled and precise manner,

landing with as little vertical velocity as possible.

Every successful test brings us a little closer to understanding the universe

and it's great mysteries.

οριακή ταχύτητα

Felix Baumgartner made history and conquered the skies

by becoming the first person to break the sound barrier without vehicular power.

Skydiving from a balloon a historic 39,068 meters above Earth's surface,

he plummeted down, reaching estimated speeds of 1,360 kilometers per hour.

Air drag is a resistive force that slows anything

moving in the Earth's atmosphere.

When Felix is free falling, the force of gravity

is constant and points downward toward the center of the Earth.

Immediately upon jumping, this is the only force acting on him.

At lower velocities, the effects of air drag can be ignored.

But during high speed phenomena, air drag must be included.

Air drag always opposes the direction of motion.

While the force of gravity is constant, air drag

rapidly increases with velocity.

If the velocity gets large enough, the force of air drag

will equal the force of gravity and cancel each other out.

With no acceleration, Felix's velocity will remain constant from this point

until his parachute opens.

This is terminal velocity.

Without understanding the fundamental physics behind the fall,

Felix could easily have made mistakes and not survived the jump.

Understanding the laws of physics make seemingly impossible feats achievable.