High-voltage physics - with David Ricketts

The video begins with an introduction to a science demonstration involving static electricity. The presenter invites Mike to participate in a demonstration where a charged rod with a butterfly is used to show the principle of like charges repelling each other. The audience is engaged with humor and a trick involving metal clacking. The presenter then explains the concept of charging objects using friction, known as the tribal electric effect, and introduces a demonstration ball to explain the creation of positive and negative charges through friction. The use of a wand with colors to signify charge polarity is also discussed, followed by a demonstration involving polystyrene plates and the creation of static electricity through rubbing with different materials.

The paragraph delves into the definition of positive and negative charges, explaining the historical context of their naming by Benjamin Franklin. It is highlighted that the polarity is determined by the material used for rubbing, as demonstrated by the use of a glass rod and Teflon. The presenter then discusses the origin of the word 'electricity' from the Greek word for amber, and how static charge was initially created by rubbing amber. The talk's progression from low to high voltage is introduced, along with a demonstration of induction, where a charge is induced on a can and a balloon, showing the attraction between opposite charges.

The presenter explains the concept of generating high voltages using the method of induction. A demonstration is conducted using a Van de Graaff Generator to show how charge is induced and separated to create a difference in charge, which is a method for generating higher voltages. The presenter also discusses the limitations of charge transfer when potentials are equal and introduces the concept of electro forests, using a fur-rubbed plate to demonstrate the induction of charge on a neon bulb. The paragraph concludes with a discussion on the misconception of free energy and the actual work involved in pumping charge in and out.

The presenter introduces Lord Kelvin's water dropper, a device that demonstrates the creation of charge from nothing using water. The process involves water droplets falling and inducing charge, which is then transferred to a separate device. The presenter also discusses the concept of potential energy and voltage, using two beakers of water to illustrate the transfer of charge when there is a difference in potential. The operation of the water dropper is explained, showing how it uses induction and gravity to create and separate charges, leading to the building up of voltage.

The Wimshurst machine is introduced as a device that generates charge through induction, not friction as commonly believed. The presenter explains the mechanism of the machine, involving two metal pieces that induce a charge. A classic demonstration involving a hunter and birds made of charged objects is shown, where the birds fly apart due to having the same charge. The presenter also discusses the history of the Wimshurst machine and its significance in the context of The Royal Institution. The paragraph concludes with a discussion on the principles of charge generation in the Wimshurst machine and its ability to build up charge through induction.

The presenter uses a Wimshurst machine to demonstrate the concept of a lightning rod and its function in protecting structures from lightning strikes. A model house is used to show the effects of an unprotected house versus one protected by a lightning rod. The presenter also humorously discusses the safety precautions taken during the demonstration and the dramatic effect of an unprotected house being 'struck' by lightning. The demonstration emphasizes the importance of lightning rods in safeguarding against electrical discharges.

The presenter discusses the Van de Graaff Generator, explaining its operation and the key innovation that makes it special. The generator's ability to generate high voltages up to 100,000 volts is demonstrated, with the presenter highlighting the role of the Faraday cage in the process. The Faraday cage allows for the continuous flow of charge into the generator, with the potential inside being zero. The presenter also shows the process of charge being added to the generator and the limitations encountered when trying to increase the potential beyond certain levels. The explanation concludes with a discussion on the principles of charge transfer and the unique design of the Van de Graaff Generator.

The presenter introduces the Ruhmkorff coil, explaining its function in generating high voltages through electromagnetic induction. The coil's design, consisting of two coils with different numbers of turns, is described, along with its ability to multiply the voltage from the primary coil to the secondary coil. The presenter also discusses the relationship between the voltage produced and the speed of current change. The practical application of the Ruhmkorff coil in petrol cars is mentioned, with a demonstration showing the coil's ability to generate a spark for the spark plug. The paragraph concludes with a discussion on the applications of high voltage and the potential for using the Ruhmkorff coil in various devices.

The presenter demonstrates the application of high voltage in ion thrusters, showing how an electric field can rip electrons off air molecules and accelerate ions to create airflow. A smaller version of an ion thruster is used to generate a significant amount of air movement. The concept of an ion spacecraft is introduced, followed by a demonstration of an ion lifter, which uses a sharp wire to create ions that are accelerated towards smoother surfaces, resulting in lift. The presenter also discusses the creation of plasma, a collection of charged particles, and its potential applications. The paragraph concludes with a dramatic demonstration of a Ruhmkorff machine creating a vacuum and the formation of a plasma stream.

The presenter explores the concept of plasma through various demonstrations, starting with the unexpected phenomenon of a grape catching fire in a microwave due to resonance with the microwave's frequency. The presenter then attempts to create a plasma within a microwave by ionizing the air with a candle flame. A historic demonstration known as Gassiot's Fountain is recreated using a Ruhmkorff coil and a glass goblet filled with uranium-impregnated green glass. The presenter explains the process of creating a vacuum and the formation of a plasma fountain around the glass goblet, highlighting the impressive visual effect this would have had in the late 1800s at The Royal Institution.

The presenter showcases the creation of a plasma toroid using an oscillator and a bespoke globe filled with xenon gas. The demonstration involves circulating a current to create a magnetic field, which induces charge circulation and results in the formation of a self-sustained plasma toroid inside the globe. The presenter also discusses the historical significance of the Tesla coil, recounting Nikola Tesla's demonstration at The Royal Institution in 1890. Two Tesla coils are used to play music, showcasing their ability to generate high voltages and create electrical resonance. The paragraph concludes with a duet between the two coils and a discussion on the safety and historical context of these demonstrations.

The presenter concludes the demonstration by highlighting the musical capabilities of Tesla coils, using them to play upbeat electric music. The idea of a duet between two coils is entertained, and the presenter asks the audience to recall the promised million-volt demonstration. A significant spark is generated, and the presenter humorously asks to be wished luck before entering a Faraday cage to demonstrate its safety. The director of science engagement, Daniel Glaser, thanks the demo team and the presenter, Dr. David Ricketts, for their contributions and the unique demonstrations provided, emphasizing the historical and cutting-edge nature of the evening's presentations.