Van de Graaff Generator, High Voltage - SE-8691



The High Voltage Van de Graaff Generator features a 25 cm sphere which can generate approximately 400,000 Volts. The size of the sphere, the rounded edges of the sphere and the height of the sphere from the demonstration table contribute to the high voltages generated.

Its large size, long sparks and high voltages make it ideal for use in larger rooms or lecture halls. An extra belt is included.

Electric charges

Convince skeptical students of the existence of charges with a couple of simple demonstrations.

  • The PASCO Electrostatic Whirl (SE-7233) will collect charge when held near the Van de Graaff Generator. The charge will then escape through the tips of the spinner causing it to spin. Why? Something must be pushing the spinner around and, by Newton's Third Law, something must therefore be being pushed off.
  • Unfold a paper clip into an "L" shape and tape it to the surface of the Van de Graaff Generator with the long side pointing straight out from the surface. With the Generator running, have students hold their hand over the point. Students should feel a breeze as charges streaming off the point collide with air molecules and get them moving. Students will also discharge at some point, and the shocks should provide a convincing argument that they were collecting charges.

The attraction and repulsion of charges

The tendency of like charges to repel each other can be clearly shown with a few entertaining demonstrations.

  • The PASCO Electrostatic Plume (SE-7232) is placed on the Van de Graaff Generator when it is running. Charges will flow into the plume's streamers and the charged streamers will float up as the charge they carry repel each other.
  • Always a demonstration favorite, a student volunteer stands on an insulating object, such as a wooden chair, and places their hand on the sphere of the Van de Graaff Generator. As the Van de Graaff Generator runs, charger will flow into the student right out to their hair, which, being all the same charge, will float up as they repel each other. Just make sure to warn them about getting shocked when they ground!
  • For a spectacular, and spectacularly messy, demonstration, tape a plastic or foam bowl to the top of the non-running Van de Graaff Generator and fill it with crisped rice cereal. Turn the Van de Graaff Generator on for a delightful fountain of cereal as the charged, untethered bits of cereal fly away from each other.

The existence of electric fields, their concentration at points, and electric potential (voltage)

Moving charge takes the path of least resistance which, through an insulator such as air, is along electric field lines. The stronger the field, the more charge moves in that region. Electric field strength is concentrated at the point of a conductor.

  • The PASCO Electrostatic Whirl (SE-7233) works because the charge on it creates an electric field. The tips of the spinner arms, being pointed, concentrate the electric field. Because the field is stronger there than along the arms, the majority of charges will leave from the tips.
  • A paper clip taped to the surface of the Van de Graaff Generator creates a point on the otherwise smooth sphere. Because this point concentrates the electric filed here, the majority of leaking charge will leave the sphere at this location, creating an easily felt breeze as the charges collide and accelerate intervening air molecules.
  • A fluorescent tube in the vicinity of a Van de Graaff Generator will light up when held so its length runs radially from the Van de Graaff Generator. The Van de Graaff Generator's electric field creates a potential (or voltage) difference from one end of the tube to the other. This voltage difference gets charges to flow in the tube, causing it to light up as if plugged in.


  • Large 25 cm dome for easy visibility
  • Sparks of up to 35 cm in length
  • Tall lucite column keeps sphere far above the base, allowing a large voltage generation, and is thick-walled to withstand years of use
  • Variable speed motor to adjust charge buildup
  • Belt is easy to replace (one extra belt included)


  • Van de Graaff Generator, High Voltage
  • Installed belt
  • Replacement belt
  • How It Works

    The principles behind the operation of the Van de Graaff Generator are surprisingly straightforward, and teaching how the machine works can reinforce the electricity concepts being taught.


    Sphere diameter
    • 25 cm
    Overall height
    • 74 cm

    Buying Guide

    Charge Producers and Proof Plane
    Conductive Spheres
    Faraday Ice Pail
    Basic Variable Capacitor
    Basic Electrometer
    Electrostatics Voltage Source
    Charge Producers and Proof Plane   ES-9057C
    Conductive Spheres   ES-9059C
    Faraday Ice Pail   ES-9042A
    Basic Variable Capacitor   ES-9079
    Basic Electrometer   ES-9078A
    Electrostatics Voltage Source   ES-9077
    Replacement Belt, Van de Graaff generator
    Replacement Parts
    Replacement Belt, Van de Graaff generator   SE-7355