Anti-Gravity Wheel?

Veritasium
17 Mar 201405:41
EducationalLearning
32 Likes 10 Comments

TLDRIn a remarkable demonstration at the University of Sydney, a forty-pound flywheel attached to a meter-long shaft is shown to defy gravity when spun at high speeds. The presenter, initially struggling to lift the stationary wheel, effortlessly raises it overhead once spinning, illustrating the principles of gyroscopic precession. The experiment further explores the effect by measuring the presenter's weight with and without the spinning flywheel, challenging viewers to predict the scale's reading during the lift.

Takeaways
  • 🏋️‍♂️ The demonstration involves a forty-pound (nineteen-kilogram) flywheel on a meter-long shaft.
  • 🤔 Holding the flywheel horizontally with one hand at rest is virtually impossible due to its weight.
  • 💫 When the flywheel is spun to a few thousand RPM, it can be held horizontally from one end without difficulty.
  • 🔄 The phenomenon at play is gyroscopic precession, which counteracts the expected pull of the wheel towards the ground.
  • 👨‍🔬 The presenter attempts to lift the spinning flywheel over their head with one hand, showcasing its seemingly weightless feel.
  • 🏋️‍♀️ The presenter initially struggles to lift the flywheel without it spinning, highlighting the difference in effort required when it's not in motion.
  • 📈 A scale reading experiment is proposed to measure the apparent weight change when lifting the spinning flywheel.
  • 🔢 The scale reading with the flywheel at rest is 72 kilograms, increasing to 91 kilograms when the flywheel is lifted.
  • 🤷‍♂️ The presenter challenges the viewer to predict the scale reading while lifting the spinning flywheel over their head.
  • 🎥 A video on gyroscopic precession is mentioned for a more detailed explanation of the phenomenon.
  • 🙏 The presenter's experience of lifting the spinning flywheel feels effortless, contrary to the actual weight of the object.
Q & A

  • What is the weight and size of the flywheel mentioned in the transcript?

    -The flywheel weighs forty pounds or nineteen kilograms and is on the end of a meter-long shaft.

  • Why is it difficult to hold the flywheel horizontally without spinning it?

    -Holding the flywheel horizontally without spinning it is difficult because of its significant weight and the leverage created by its length, making it almost impossible to hold with one hand.

  • What happens when the flywheel is spun up to a few thousand RPM and then held horizontally?

    -When the flywheel is spun up to a few thousand RPM and held horizontally, the shaft remains horizontal and the wheel appears almost weightless due to the effect of gyroscopic precession.

  • What is gyroscopic precession and how does it apply to the flywheel demonstration?

    -Gyroscopic precession is a phenomenon where the rotation of a spinning body resists any change in its orientation. In the flywheel demonstration, the precession counteracts the force of gravity, making the wheel seem weightless when spun at high speeds.

  • What does the speaker attempt to do after spinning the flywheel?

    -The speaker attempts to lift the spinning flywheel over their head using only one hand while it is spinning.

  • Why does the speaker struggle to lift the flywheel above their head without it spinning?

    -The speaker struggles to lift the flywheel above their head without it spinning because the full weight of the flywheel, without the counteracting effect of gyroscopic precession, is difficult to manage with one hand.

  • How does the speaker ensure the flywheel is spinning fast enough for their attempt?

    -The speaker ensures the flywheel is spinning fast enough by giving it ten more seconds to spin up before attempting to lift it over their head.

  • What is the result of the speaker's attempt to lift the spinning flywheel over their head?

    -The speaker successfully lifts the spinning flywheel over their head, describing the sensation as incredibly light due to the effects of gyroscopic precession.

  • What experiment is suggested to further demonstrate the effects of lifting the spinning flywheel?

    -The suggested experiment is for the speaker to stand on a scale while lifting the spinning flywheel over their head to measure any changes in weight, essentially to see if the speaker gets lighter during the lift.

  • What is the initial weight measured on the scale with just the speaker?

    -The initial weight measured on the scale with just the speaker is about 72 kilograms.

  • How does the scale reading change when the speaker picks up the non-spinning flywheel?

    -When the speaker picks up the non-spinning flywheel, the scale reading goes up to about 91 kilograms, accounting for the weight of the flywheel.

  • What prediction is being asked of the viewer regarding the scale reading while the speaker lifts the spinning flywheel over their head?

    -The viewers are asked to predict whether the scale reading will be more, less than, or equal to 91 kilograms when the speaker lifts the spinning flywheel over their head.

Outlines
00:00
🏋️‍♂️ The Challenge of Lifting a Spinning Flywheel

In this segment, the presenter is at the University of Sydney, where a mechanical engineering shop has constructed a unique apparatus for demonstration. The apparatus consists of a forty-pound (nineteen-kilogram) flywheel attached to a meter-long shaft. The presenter humorously attempts to hold the flywheel horizontally by one end, highlighting the difficulty of the task due to its weight. The demonstration then moves on to spinning the flywheel at high speeds (a few thousand RPM) and releasing it, showing that the flywheel remains horizontal due to gyroscopic precession. The presenter further challenges the phenomenon by attempting to lift the spinning flywheel over his head with one hand, emphasizing the surprising ease of the task despite the flywheel's considerable weight. The segment concludes with an experiment to measure the apparent weight of the presenter and the flywheel using a scale, with the flywheel adding about 19 kilograms to his weight when not spinning, and a prediction is made about the scale's reading while he lifts the spinning flywheel overhead.

05:04
📈 The Scale Experiment: Perception vs. Reality

This paragraph presents an interactive element where the audience is invited to predict the outcome of an experiment involving the scale reading while the presenter lifts the spinning flywheel over his head. The question posed is whether the scale will show a reading more, less, or equal to 91 kilograms, which is the combined weight of the presenter and the flywheel at rest. The audience can make their predictions through on-screen annotations or a link in the video description. The segment ends with a countdown, building anticipation for the experiment's result.

Mindmap
Keywords
💡flywheel
A flywheel is a rotating mechanical component that stores energy in its rotational kinetic energy. In the video, the flywheel is a significant piece of apparatus, a forty-pound (nineteen-kilogram) wheel on the end of a meter-long shaft, which demonstrates the principles of gyroscopic precession and torque when spun at high speeds. The flywheel's ability to appear 'weightless' when spinning is a central theme of the demonstration.
💡torque
Torque is a measure of the force that can cause an object to rotate about an axis. In the context of the video, the weight of the flywheel creates a torque that pushes it around in a circle, which is a key factor in the demonstration of the flywheel's 'weightlessness' when spun. Torque is essential in understanding how the flywheel's rotation counteracts its weight.
💡gyroscopic precession
Gyroscopic precession is a phenomenon where the axis of a rotating body experiences a force that causes it to move in a direction perpendicular to the applied force. In the video, this concept is what allows the heavy flywheel to appear weightless when spun at high speeds; the precession counteracts the force of gravity, making it seem as though the wheel is not affected by its weight.
💡RPM (Revolutions Per Minute)
Revolutions Per Minute (RPM) is a measure of the number of rotations a wheel or an object makes around its axis in one minute. In the video, the flywheel is spun up to a few thousand RPM, which is critical for the demonstration of its weightlessness and the gyroscopic precession effect.
💡weightlessness
Weightlessness is the state in which an object appears to have no weight, often experienced in freefall or in space. In the video, the spinning flywheel gives the illusion of weightlessness due to the gyroscopic precession, making it seem as though it requires little effort to hold despite its actual weight.
💡shaft
A shaft is a straight structural component that transmits power, force, or motion. In the video, the flywheel is attached to the end of a meter-long shaft, which is used to spin the flywheel and demonstrate the effects of its rotation.
💡scale
A scale is a device for measuring weight. In the video, the presenter uses a scale to demonstrate the actual combined weight of themselves and the flywheel, as well as to test a prediction about the scale's reading when the flywheel is lifted over their head while spinning.
💡lifting
Lifting is the act of raising an object from a lower to a higher position, usually by applying an upward force. In the video, the presenter attempts to lift the heavy flywheel over their head while it is spinning, which becomes easier due to the effects of gyroscopic precession.
💡precession
Precession is the change in the orientation of a rotating body. In the context of gyroscopic precession, it refers to the tilt or change in the axis of rotation caused by an external force, which in the video, is the weight of the flywheel. This concept is crucial to understanding the flywheel's behavior when spun and lifted.
💡mechanical engineering
Mechanical engineering is a discipline of engineering that applies the principles of physics for analysis, design, manufacturing, and maintenance of mechanical systems. In the video, the mechanical engineering shop at the University of Sydney has built the flywheel apparatus used for the demonstration, showcasing the practical application of mechanical engineering principles.
💡University of Sydney
The University of Sydney is an institution of higher education located in Sydney, Australia. In the video, the demonstration takes place at this university, highlighting the academic setting and the role of educational institutions in scientific exploration and demonstration.
Highlights

The University of Sydney's mechanical engineering shop built an impressive apparatus.

The apparatus consists of a 40-pound (19 kg) flywheel on a meter-long shaft.

Holding the apparatus horizontally with one hand at the end is virtually impossible.

Spinning the flywheel up to a few thousand RPM allows it to be held horizontally from one end.

The spinning flywheel appears almost weightless due to gyroscopic precession.

A detailed explanation of gyroscopic precession is provided in a linked video.

An attempt to lift the spinning flywheel over the head with one hand is successful.

Lifting the flywheel above the head without spinning is challenging.

The spinning flywheel feels incredibly light when lifted over the head.

The experimenter's lack of strength does not hinder the lifting of the spinning flywheel.

The flywheel's spinning motion seems to assist in lifting it upwards.

The scale reading increases from 72 kg to 91 kg when the flywheel is lifted.

The flywheel adds approximately 19 kg to the total weight.

A prediction is made on whether the scale reading will change when lifting the flywheel over the head.

The experiment demonstrates the counterintuitive effects of gyroscopic precession on weight perception.

The experiment is a practical application of theoretical physics principles.

The apparatus and experiment showcase the power of mechanical engineering.

Transcripts

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