Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Buoyancy and Stability for Submerged and Floating Bodies01:11

Buoyancy and Stability for Submerged and Floating Bodies

In fluid mechanics, buoyancy and stability are key concepts for understanding the behavior of submerged and floating bodies. When a stationary body is fully or partially submerged in a fluid, the fluid exerts a force on the body known as the buoyant force. This force acts vertically upward through a point called the center of buoyancy, which is the center of the displaced fluid volume. According to Archimedes' principle, the magnitude of the buoyant force is equal to the weight of the fluid...
Intestinal Obstruction II: Pathophysiology01:07

Intestinal Obstruction II: Pathophysiology

Intestinal obstruction triggers a series of physiological responses, starting with gas and fluid accumulation in the bowel segment proximal to the obstruction, leading to distension. This distended intestine compresses the diaphragm, hindering lung expansion and potentially leading to reduced respiratory effort, atelectasis, and pneumonia.To overcome the blockage, the gut intensifies contractions, causing colicky abdominal pain, nausea, and vomiting, which reduces fluid and food intake and...
Design Example: Application of Archimedes' Principle01:11

Design Example: Application of Archimedes' Principle

Archimedes' principle is fundamental in analyzing the buoyant force and stability of floating bodies. In this example, a wooden block with a rectangular section floats in seawater. Based on the block's dimensions, its specific gravity and the specific weight of seawater are used to find the volume of water displaced and the center of buoyancy.
The volume of seawater displaced by the block is determined by first calculating the block's weight. This is done by multiplying the block's volume by...
Pulmonary Embolism I: Introduction01:29

Pulmonary Embolism I: Introduction

Pulmonary embolism (PE) occurs when a thrombus, fat or air embolus, amniotic fluid, or tumor tissue blocks one or more pulmonary arteries. These blockages originate in the venous system or the right side of the heart.EtiologyPE primarily arises from deep vein thrombosis (DVT) and other hypercoagulable states, such as inherited thrombophilias. Additional etiological factors include venous stasis, commonly seen in obesity, and endothelial injury from surgery and trauma. Less common causes include...
Pulmonary Embolism I: Introduction01:19

Pulmonary Embolism I: Introduction

A blood clot, or thrombus, is a semi-solid mass composed of fibrin, platelets, and red blood cells. When it forms within a vessel, it can obstruct blood flow, known as thrombosis. If part of the clot detaches, it becomes an embolus that can travel and block distant vessels. When this occurs in the pulmonary arteries, it causes a condition known as pulmonary embolism (PE).Origin and ImpactMost often, the embolus originates from a thrombus in the deep veins of the lower limbs, a condition called...
Buoyancy01:12

Buoyancy

When an object is placed in a fluid, it either floats or sinks. All objects in a fluid experience a buoyant force. For example, a metal ball sinks, while a rubber ball floats. Similarly, a submarine can sink and float by adjusting its buoyancy.  The concept of buoyancy raises several interesting questions. For instance, where does this buoyant force come from? How much buoyant force is required to make an object sink or float? Do objects that sink get any support at all from the fluid? 
To get...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Nonspecular mechanism for chaotic ray scattering of internal waves in three-dimensional anisotropic stadiums.

Physical review. E·2025
Same author

Concurrent validity and discriminative ability of Dutch performance-based motor tests in 5 to 6 years old children.

PloS one·2019
Same author

Differences in swimming smoothness between elite and non-elite swimmers.

Sports biomechanics·2019
Same author

School-Based Physical Activity Interventions in Prevocational Adolescents: A Systematic Review and Meta-Analyses.

The Journal of adolescent health : official publication of the Society for Adolescent Medicine·2019
Same author

Heart-Rate Recovery After Warm-up in Swimming: A Useful Predictor of Training Heart-Rate Response?

International journal of sports physiology and performance·2016
Same author

Biophysical Determinants of Front-Crawl Swimming at Moderate and Severe Intensities.

International journal of sports physiology and performance·2016
Same journal

Gone with the wind: wind-induced web movement reduces kleptoparasite abundance in a golden orbweaver spider.

Die Naturwissenschaften·2026
Same journal

A survey of Eocene stomach contents illuminates the origins of frugivory and seed dispersal in neornithine (crown group) birds.

Die Naturwissenschaften·2026
Same journal

Could snort production reflect comfort in horses kept outdoors? A first study.

Die Naturwissenschaften·2026
Same journal

Pyrazole-thiazolidine hybrids as α-amylase inhibitor: a mechanistic and computational investigation.

Die Naturwissenschaften·2026
Same journal

Conventional methods may cause allometric analyses to be unreliable.

Die Naturwissenschaften·2026
Same journal

Impact of habitat disturbance on activity pattern and diet of de brraza's monkey (Cercopithecus neglectus) in kafa biosphere reserve, South West Ethiopia.

Die Naturwissenschaften·2026
See all related articles

Related Experiment Video

Updated: Jun 27, 2026

Assessment of Swim Endurance and Swim Behavior in Adult Zebrafish
09:36

Assessment of Swim Endurance and Swim Behavior in Adult Zebrafish

Published on: November 12, 2021

Swimming obstructed by dead-water.

Sander P M Ganzevles1, Fons S W van Nuland, Leo R M Maas

  • 1Research Institute MOVE, Faculty of Human Movement Sciences, VU University, Van der Boechorststraat 9, 1081 BT, Amsterdam, The Netherlands.

Die Naturwissenschaften
|December 17, 2008
PubMed
Summary
This summary is machine-generated.

Dead-water, an effect seen in ships, can also hinder swimmers. Studies show stratified water significantly reduces swimming speed and propulsive power, potentially explaining strange water sensations and increasing drowning risk.

More Related Videos

A Rapidly Incremented Tethered-Swimming Maximal Protocol for Cardiorespiratory Assessment of Swimmers
09:24

A Rapidly Incremented Tethered-Swimming Maximal Protocol for Cardiorespiratory Assessment of Swimmers

Published on: January 28, 2020

Swimming Performance Assessment in Fishes
05:12

Swimming Performance Assessment in Fishes

Published on: May 20, 2011

Related Experiment Videos

Last Updated: Jun 27, 2026

Assessment of Swim Endurance and Swim Behavior in Adult Zebrafish
09:36

Assessment of Swim Endurance and Swim Behavior in Adult Zebrafish

Published on: November 12, 2021

A Rapidly Incremented Tethered-Swimming Maximal Protocol for Cardiorespiratory Assessment of Swimmers
09:24

A Rapidly Incremented Tethered-Swimming Maximal Protocol for Cardiorespiratory Assessment of Swimmers

Published on: January 28, 2020

Swimming Performance Assessment in Fishes
05:12

Swimming Performance Assessment in Fishes

Published on: May 20, 2011

Area of Science:

  • Fluid dynamics
  • Human physiology
  • Oceanography

Background:

  • Dead-water is a known phenomenon in nautical literature, describing ship obstruction in stratified water.
  • Anecdotal evidence from swimmers suggests unusual water behavior can occur, potentially leading to dangerous situations.

Purpose of the Study:

  • To investigate if dead-water phenomena obstruct open-water swimming.
  • To quantify the impact of stratified water on swimming performance and energy expenditure.

Main Methods:

  • Two experiments were conducted: assessing stroke energy gain on a rolling carriage in stratified vs. homogeneous water, and measuring swimming speed over 5m in varying stratified conditions.
  • Subjects performed front-crawl strokes, and swimming velocity and stroke frequency were recorded.

Main Results:

  • Kinetic energy gain from a single stroke was significantly lower in stratified water compared to homogeneous water.
  • Swimmers experienced a 15% decrease in speed and a 40% loss in propulsive power in stratified conditions at the same stroke frequency.
  • The effect is predicted to be most pronounced in fair weather with shallow surface layer stratification.

Conclusions:

  • Dead-water effects can obstruct open-water swimming, reducing speed and power output.
  • Findings support anecdotal swimmer experiences of 'strangely behaving water'.
  • Stratified water poses a potential risk factor for swimmers, particularly in calm, fair weather conditions.