• Rowlanda – Rowland’s Rotating Charged Disc Physics Sticker

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Rowlanda

Rowland’s Rotating Charged Disc Physics

$4.99 USD
$4.99 USD
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Rowlanda, a bearded experimenter, spins a glowing charged disc beside a compass.

The Physics

In 1876, in Helmholtz's Berlin laboratory, Henry Rowland charged an ebonite disc and spun it fast. A magnetic needle nearby deflected (Am. J. Sci. 15, 30, 1878). A moving charge makes a magnetic field, just as a current in a wire does: current is charge in motion.

B ∝ q v

  • B: magnetic field near the disc (T)
  • q: charge on the disc (C)
  • v: rim speed (m/s)

It answered whether ‘convection’ of charge counts as a current: it does.

Honest caveat: The deflection was tiny, a fraction of Earth's field; the full Biot–Savart form is needed for real numbers.

On the sticker

Rowlanda spins a glowing cyan disc in one hand, with a brass compass beside it. Printed text: ROWLANDA. Pixel-art kiss-cut vinyl sticker, white, in 2″, 3″, 4″ and 6″ sizes.

Shipping calculated at checkout by destinationMade to order, ships in 2–5 business days

Details

Size3″ × 3″

3″ × 3″ kiss-cut sticker.

Shipping

Shipping calculated at checkout by destination. Printed to order for you.

Delivery times & where we ship

Returns & replacements21 days

Every item is printed to order, so we can’t accept returns or exchanges for change of mind, or if you ordered the wrong size or colour.

Print defect, misprint, damage or the wrong item? We’ll send a free replacement, or a refund if you prefer. Report it within 21 days of delivery with a photo; no need to send it back.

Full refund & replacement policy

Field notes

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