World's Simplest Electric Train

A dry cell, two magnets and a coil: very simple and surpringly effective.

 

Hewitt-Drew-it! 101. Magnetism

From bar magnets to electric motors.

 

Magnetic Hair

MIT engineers have fabricated a new elastic material coated with microscopic, hairlike structures that tilt in response to a magnetic field. (Learn more about these structures: http://bit.ly/1y2E8SX) Depending on the field's orientation, the microhairs can tilt to form a path through which fluid can flow; the material can even direct water upward, against gravity.

 

How Magnets Produce Electricity 1954 US Navy Electromagnetism Prime

How a magnetic field effects a single atom, a group of atoms and a wire in a closed circuit with a meter.

 US Navy training film MN-8016b

 

Magnetic Levitation

Diamagnetism and magnetic levitation.

NASA | Canyon of Fire on the Sun

A magnetic filament of solar material erupted on the sun in late September, breaking the quiet conditions in a spectacular fashion. The 200,000 mile long filament ripped through the sun's atmosphere, the corona, leaving behind what looks like a canyon of fire. The glowing canyon traces the channel where magnetic fields held the filament aloft before the explosion. Visualizers at NASA's Goddard Space Flight Center in Greenbelt, Md. combined two days of satellite data to create a short movie of this gigantic event on the sun.

 

Motion of Electric Charges in a Uniform Magnetic Field

This animation portrays the motion of an electric charge in a uniform magnetic field. Starting with the special case where the initial motion is perpendicular to the magnetic field, we see that the motion is circular. The frequency of this circular motion (the cyclotron frequency) does not depend upon the speed of the charge. When generalizing the charge's motion to the full 3-D case, we see that the charge's will spiral along (and around) magnetic field lines.

 

MAGNETS: How Do They Work?

How do magnets work? Why do they attract and repel at long distances? Is it magic? No... it's quantum mechanics, and a bit more, as we explain in this, the longest MinutePhysics video ever.

 

 Magnetism seems like a pretty magical phenomenon. Rocks that attract or repel each other at a distance - that's really cool - and electric current in a wire interacts in the same way. What's even more amazing is how it works. We normally think of special relativity as having little bearing on our lives because everything happens at such low speeds that relativistic effects are negligible. But when you consider the large number of charges in a wire and the strength of the electric interaction, you can see that electromagnets function thanks to the special relativistic effect of length contraction. In a frame of reference moving with the charges, there is an electric field that creates a force on the charges. But in the lab frame, there is no electric field so it must be a magnetic field creating the force. Hence we see that a magnetic field is what an electric field becomes when an electrically charged object starts moving.

 

NASA | Tracking Energy through Space

This short video features commentary by David Sibeck, project scientist for the THEMIS mission, discussing a visualization of reconnection fronts.

 Taking advantage of an unprecedented alignment of eight satellites through the vast magnetic environment that surrounds Earth in space, including NASA's ARTEMIS and THEMIS, scientists now have comprehensive details of the energy's journey through a process that forms the aurora, called a substorm.
Their results showed that small events unfolding over the course of a millisecond can result in energy flows that last up to half an hour and cover an area 10 times larger than Earth.

 Trying to understand how gigantic explosions on the sun can create space weather effects involves tracking energy from the original event all the way to Earth. It's not unlike keeping tabs on a character in a play with many costume changes, because the energy changes form frequently along its journey: magnetic energy causes eruptions that lead to kinetic energy as particles hurtle away, or thermal energy as the particles heat up. Near Earth, the energy can change through all these various forms once again.

 Most of the large and small features of substorms take place largely in the portion of Earth's magnetic environment called the magnetotail. Earth sits inside a large magnetic bubble called the magnetosphere. As Earth orbits around the sun, the solar wind from the sun streams past the bubble, stretching it outward into a teardrop. The magnetotail is the long point of the teardrop trailing out to more than 1 million miles on the night side of Earth. The moon orbits Earth much closer, some 240,000 miles away, crossing in and out of the magnetotail.

 

How to Destroy a Magnet (+ interactive periodic table)

Magnets are amazingly strong... but there's a very easy way to destroy them. All you need to know is a little bit about ferromagnetism, paramagnetism, and temperature!

 

The Aurora Borealis

This video explains how particles originating from deep inside the core of the sun creates northern lights, also called aurora borealis, on our planet.

See an extended multimedia version of this video at forskning.no (only in Norwegian).

All the animated parts of the video was made with Apple Motion 4.

 

Lorentz Force in Action

A tin foil speaker experiment. Which means: Playing music through a tin foil. ;-)

 

Curie Point of Iron

A piece of iron is suspended with a copper wire at the height of one pole of a magnet. At first the iron is attracted to the magnet. The iron is then heated with a torch and eventually falls from the magnet. As the iron cools it will again be attracted to the magnet.

 

ScienceCasts: The Sun's Magnetic Field is About to Flip

Something big is happening on the sun. The sun's global magnetic field is about to flip, a sign that Solar Max has arrived.

 

DC Motor

A DC current is sent around a wire loop that is free to rotate. The current causes the loop to feel a torque in the presence of a magnetic field. Switching the current when the loop flips over allows it to continue accelerating, demonstrating the principle of a DC motor and the Lorentz force law.

 

NASA | X Marks the Spot: SDO Sees Reconnection

Two NASA spacecraft have provided the most comprehensive movie ever of a mysterious process at the heart of all explosions on the sun: magnetic reconnection.

Magnetic reconnection happens when magnetic field lines come together, break apart, and then exchange partners, snapping into new positions and releasing a jolt of magnetic energy. This process lies at the heart of giant explosions on the sun such as solar flares and coronal mass ejections, which can fling radiation and particles across the solar system.

 

How epic solar winds make brilliant polar lights - Michael Molina

Why do we see those stunning lights in the northern- and southernmost portions of the night sky? The Aurora Borealis and Aurora Australis occur when high-energy particles are flung from the Sun's corona toward the Earth and mingle with the neutral atoms in our atmosphere -- ultimately emitting extraordinary light and color. Michael Molina explains every step of this dazzling phenomenon. Lesson by Michael Molina, animation by Franco Barroeta.

 

MAVEN Magnetometer

MAVEN's dual magnetometers will allow scientists to study the interaction between the solar wind and the Martian atmosphere, giving us a better understanding of how Mars has evolved from a warm, wet climate to the cold, arid one we see today.

 

Tutorial and Experiments on Magnetic Levitation

In this episode Shahriar demonstrates one of the simplest magnetic levitation circuits. First, the basic concept of magnetic levitation is examined. Two different methods of detecting the location of the levitating object is presented and the Hall effect sensor method is chosen. A semi-digital overall system is implemented where a PWM control IC is employed to control the magnetic field strength. The block diagram and functionality of this IC is presented. Finally, the schematic of a dual-Hall effect sensor solution is presented. The circuit is built and tested in both open-loop and close-loop configuration. Magnetic levitation is demonstrated with the capability of adjusting the levitation location. The schematic of circuit can be downloaded from The Signal Path website.

 

Exotic Metals vs. Magnet (including uranium)

Magnetic properties of various metals.