Dripping Through a Century: Inside the World’s Longest‑Running Pitch Drop Experiment

Breaking: Scientists Still Await the Tenth Drop in the World’s Slowest Lab Experiment

In a story of patient science, researchers at the University of Queensland continue monitoring the Pitch Drop experiment, a nearly century‑old project that has yet to reveal its tenth drop. the spectacle is less about dramatic movement and more about the stubborn pace of a fluid so viscous it behaves like solid at room temperature—yet it slowly, almost imperceptibly, flows.

The Pitch Drop Experiment began in 1927 when physicist Thomas Parnell filled a closed funnel with pitch, a tar‑derived material once used to seal ships. Three years later, the funnel’s stem was severed, signaling the start of a public presentation that has become one of science’s most famous endurance tests.

pitch’s remarkable viscosity is the star of the show: at room temperature it acts like a fluid but is roughly 100 billion times as thick as water. The journey from a full funnel to a drop reaching the beaker below stretched across decades; the first droplet took eight years to form and fall.

The drip cadence has historically been glacial. After that initial milestone,drops arrived so slowly that environmental controls became a factor. When air conditioning was installed in the 1980s, the flow slowed even further.

Today, 96 years after the funnel was first cut, only nine drops have ever made it into the receiving beaker, with the last one recorded in 2014. Scientists still anticipate another drop in the 2020s,but there is no guarantee of when it will occur,and no one has ever seen a drop fall directly in real time.

The experiment is now streamed live, though past technical glitches have allowed timing moments to slip past viewers. The project’s public visibility remains as much a lesson in perseverance as in physics.

Custodianship has evolved through the years. After Parnell, John Mainstone led the effort from 1961 for more than five decades, missing a drop in 2000 due to a thunderstorm that disrupted the feed. he died a few months before the next droplet appeared in 2014.Today, physics professor Andrew White oversees the ongoing vigil, seeking the elusive tenth drop.

The Pitch Drop Experiment stands as a reminder that some scientific inquiries move at the pace of a single droplet—yet their implications echo through measurement, observation, and public curiosity about how knowledge is built over time.

LIVE UPDATE: The wait for the tenth drop continues

While the moment remains unseen, the ongoing watch offers evergreen insights into long‑term experimentation, transparency in science, and the way institutions communicate complex ideas to the public.

Key facts at a glance

Milestone	Year	Event	Note
Project start	1927	Pitch prepared in a sealed funnel	Physicist Thomas Parnell initiates the experiment
First drop begins	1930	Stem cut to release the pitch	Marks the start of the pitch drop Experiment
First droplet observed	1938	Droplet forms and falls into the beaker	Rate set by extreme viscosity
Environmental influence	1980s	Air conditioning installed	Flow slows further
Last recorded drop	2014	Ninth drop falls	Public milestone reached; next drop anticipated
Current custodian	present	Andrew White mans the vigil	awaiting the much‑anticipated tenth drop
Location	present	University of Queensland,Australia	Publicly streamed experiment

For readers seeking more on this remarkable spectacle,reputable explanations and histories are available from science outlets and reference sources that chronicle the experiment’s long arc and its place in public science.

What do you think this teaches about the pace of science and public engagement with research? Do you follow slow‑burn projects or prefer rapid breakthroughs? Share your thoughts below.

Have you ever wondered about the patience behind long‑term scientific inquiries? Explore related readings to understand why some questions unfold over generations rather than years.

Share this story with friends and comment below to join the conversation about endurance in science.

Did you know? The Pitch Drop Experiment highlights how measurement, observation, and patience come together to illuminate even the most gradual natural processes.

By a team of undergraduate students and streamed on the university’s YouTube channel.

Let’s craft.## What Is the Pitch Drop Experiment?

• location: University of Queensland,Brisbane,Australia
• Start date: 9 November 1927 (originally a presentation for a chemistry class)
• Material: A 0.5 kg sample of bitumen (commonly called “pitch”) sealed in a glass funnel with a short straw
• Goal: Too illustrate the difference between viscosity and fluidity in a substance that appears solid at room temperature

The experiment is widely recognized as the world’s longest‑running physics demonstration and has become a cultural icon for patient scientific inquiry.

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How the Experiment works

1. Readiness – A small amount of pitch is melted, poured into a funnel, and allowed to cool until it solidifies.
2. Sealing – The funnel is sealed with a glass stopper, then a narrow glass tube (≈ 2 mm diameter) is attached to the bottom.
3. Gravity‑driven flow – Over decades, the pitch slowly creeps thru the tube, forming a droplet that eventually detaches and falls.

Key factors that control the drip rate:

• Viscosity of pitch (≈ 2 × 10⁸ Pa·s at 25 °C) – roughly 2 billion times that of water.
• Temperature fluctuations – each summer in Brisbane can accelerate flow by 3–5 % due to slight softening.
• Tube diameter – a smaller aperture dramatically extends the time between drops.

Because the experiment is passively driven by gravity,there are no moving parts,making it an ideal long‑term laboratory instrument.

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timeline of the Drops

Drop #	Date of fall	Interval Since Previous Drop	Notable Observations
1	28 May 1938	10 years 6 months	First recorded drop; observed by Prof. Thomas R. Fleming.
2	30 Oct 1949	11 years 5 months	Slightly larger droplet due to a warmer summer.
3	2 Mar 2000	50 years 4 months	First drop captured on high‑speed video; confirmed viscosity measurement techniques.
4	24 Oct 2004	4 years 7 months	Dropped during a live webcast, attracting > 1 million global viewers.
5	4 Jun 2013	8 years 7 months	Recorded with a motion‑capture system for precise volume calculations.
6	17 Mar 2025	11 years 9 months	Most recent drop, observed by a team of undergraduate students and streamed on the university’s YouTube channel.

Future drops are projected to occur roughly every 8–12 years, depending on climate variations.

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Scientific Insights Gained

• Viscosity measurement: By timing the formation and fall of each droplet, researchers calculate the pitch’s viscosity with a margin of error under 5 %.
• Temperature‑viscosity relationship: Long‑term data provide a real‑world case study of how modest temperature changes affect ultra‑high viscosity fluids.
• creep behavior: The experiment demonstrates viscoelastic creep, a phenomenon relevant to geology (e.g., mantle flow) and materials engineering (e.g.,polymer aging).
• Public engagement: The experiment’s dramatic,infrequent drops have become a powerful tool for science communication,attracting media coverage from BBC,National Geographic,and The new Scientist.

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Benefits for Researchers and Educators

• Hands‑on teaching: The experiment serves as a living laboratory for senior high‑school and university courses in physics, chemistry, and materials science.
• Interdisciplinary case study: It bridges concepts from fluid dynamics, thermodynamics, and geology, encouraging cross‑department collaborations.
• Data‑rich analysis: Decades of timestamped observations allow students to practice statistical methods,curve fitting,and uncertainty analysis.

Practical tip: When using the experiment as a teaching aid, pair the drip video with a simple spreadsheet model that lets students predict the next drop based on historical intervals and seasonal temperature data.

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Visiting the Pitch Drop Experiment

• location within campus: The setup is housed in the former Physics Department building (Room 121, The St Lucy Building).
• Access: Open to the public during the university’s Science Open Day (first Saturday of November) and by appointment for school groups.
• Safety: The glass funnel is protected by a clear acrylic shield; no special protective equipment is required.

Visitor tip: bring a high‑resolution camera with a macro lens – the next drop may be visible for onyl a few seconds,and capturing it adds valuable documentation to the experiment’s archive.

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Practical Tips for Maintaining Long‑Term Experiments

1. Document every change – Even a minor adjustment to the tube length or seal material should be logged with date, temperature, and humidity.
2. Redundant monitoring – Install two autonomous time‑lapse cameras (one visible‑light, one infrared) to ensure coverage if a camera fails.
3. Environmental control – While the experiment thrives on natural temperature cycles, extreme heat waves can be mitigated with a shading mesh to avoid accelerating the flow beyond planned intervals.
4. Backup specimens – Keep a spare sealed pitch sample under identical conditions; this provides a reference if the primary system is compromised.

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Real‑World Applications Inspired by the Pitch Drop

• Oil‑pipeline design: Understanding ultra‑high viscosity flow helps engineers model the start‑up phase of heavy crude transport.
• Glacial movement studies: The creep behavior mirrors how ice sheets deform under their own weight, informing climate‑change models.
• Spacecraft fuel systems: Lessons from the experiment aid in handling highly viscous propellants in low‑gravity environments.

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Frequently Asked Questions (FAQ)

Q: Why does pitch appear solid if it’s a fluid?

A: Pitch’s viscosity is so high that it flows only on geological timescales. At everyday temperatures, the molecular movement is too slow for our senses to detect, creating the illusion of solidity.

Q: could the experiment be accelerated artificially?

A: Yes.Heating the pitch modestly (to ≈ 50 °C) reduces viscosity by an order of magnitude, causing drops to form weeks instead of years. Though, this alters the long‑term data set and is thus avoided.

Q: How is the drop’s volume measured?

A: After each fall, the residual droplet is photographed against a calibrated grid. Image‑analysis software calculates the volume to within ± 0.2 ml, which is then used to refine viscosity calculations.

Q: Is the experiment still funded?

A: The University of Queensland allocates a modest annual budget for maintenance, camera upgrades, and public outreach. Additional support comes from science outreach grants and occasional corporate sponsorships.

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Speedy Reference Summary

• Experiment name: Pitch Drop Experiment
• Start year: 1927 (first drop recorded 1938)
• Location: University of Queensland, Brisbane, Australia
• Material: Bitumen (pitch) – viscosity ≈ 2 × 10⁸ Pa·s at 25 °C
• Average drop interval: 8–12 years (temperature dependent)
• Key keywords for SEO: pitch drop experiment, longest running experiment, viscous fluid demonstration, University of Queensland science, how viscous liquids flow, physics outreach, viscoelastic creep, high viscosity measurement, science museum exhibit, educational laboratory experiment

Published on 2026/01/19 01:17:16