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

Classifying Matter by State02:49

Classifying Matter by State

103.9K
Chemistry is the study of matter and the changes it undergoes. Matter is anything that has mass and occupies space. Matter is all around us; the air, water, soil, mountains, even our bodies are all examples of matter. Matter is divided into three states — solid, liquid, and gas — that are commonly found on earth. The fourth state of matter, plasma, occurs naturally in the interiors of stars. 
103.9K
Classifying Matter by Composition03:35

Classifying Matter by Composition

90.7K
Matter: Pure Substances and Mixtures
According to its composition, the matter can be classified into two broad categories — pure substances and mixtures. 
A pure substance is a form of matter that has a constant composition throughout with uniform properties. For example, any sample of sucrose has the same composition and same physical properties, such as melting point, color, and sweetness, regardless of the source from which it is isolated. 
A mixture is composed of two or...
90.7K
Physical and Chemical Properties of Matter02:57

Physical and Chemical Properties of Matter

166.6K
The characteristics that enable us to distinguish one substance from another are called properties.
166.6K
What is Matter?01:13

What is Matter?

103.1K
The substance of the universe—from a grain of sand to a star—is called matter. Scientists define matter as anything that occupies space and has mass. An object’s mass and its weight are related concepts, but not quite the same. An object’s mass is the amount of matter contained in the object and is the same whether that object is on Earth or in the zero-gravity environment of outer space. An object’s weight, on the other hand, is its mass as affected by the pull of...
103.1K
The Atomic Theory of Matter02:59

The Atomic Theory of Matter

128.6K
The earliest recorded discussion of the basic structure of matter comes from ancient Greek philosophers. Leucippus and Democritus argued that all matter was composed of small, finite particles that they called atomos, meaning “indivisible.” Later, Aristotle and others came to the conclusion that matter consisted of various combinations of the four “elements” — fire, earth, air, and water — and could be infinitely divided. Interestingly, these philosophers...
128.6K
States of Matter01:20

States of Matter

2.9K
Solids, liquids, and gases are the three states of matter commonly found on Earth. A solid is rigid and possesses a definite shape. A liquid flows and takes the shape of its container, except it forms a flat or slightly curved upper surface when acted upon by gravity. Both liquid and solid samples have volumes nearly independent of pressure. A gas takes both the shape and volume of its container.
Scientists have discovered a fourth state of matter, plasma, that occurs naturally in the interiors...
2.9K

You might also read

Related Articles

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

Sort by
Same author

Copy number variants reveal divergent genetic and diagnostic cortical signatures across psychiatric disorders.

Research square·2026
Same author

National recommendations for the safe handling of hazardous drugs by pharmacy technicians in Portugal: A modified delphi study.

Journal of oncology pharmacy practice : official publication of the International Society of Oncology Pharmacy Practitioners·2026
Same author

Circadian Health Training in Latin America: Translating Chronobiology into Clinical Practice.

Sleep science (Sao Paulo, Brazil)·2026
Same author

Actigraphy-Based Movement Profiles and Their Association With Circadian Rhythms Integrity in Real-World Settings.

Journal of biological rhythms·2026
Same author

Targeting NRF2 With Isoeugenol: A Promising Small Molecule for Neurodegenerative, Metabolic, and Chronic Inflammatory Disorders.

Oxidative medicine and cellular longevity·2026
Same author

Isolated Abdominal Wall Metastasis of Hepatocellular Carcinoma: A Case Report.

Cureus·2026
Same journal

Multivariate associations between sleep patterns and self-regulation in adolescence: Canonical correlation analysis across ABCD and NCANDA cohorts.

Chronobiology international·2026
Same journal

Circadian amplitude and CLOCK 3111 polymorphism predict morning leptin in Arctic residents, independent of photoperiod.

Chronobiology international·2026
Same journal

A machine learning-based analysis of chronotype and sleep quality as predictors of mental distress in university students.

Chronobiology international·2026
Same journal

Maternal depressive symptoms are not linked to infant rest-activity patterns at six months.

Chronobiology international·2026
Same journal

Circadian and metabolic effects of light-phase time-restricted feeding with a Western-style diet in young female rats.

Chronobiology international·2026
Same journal

Heart rate variability and heart rate fragmentation among shift workers: The Multi-Ethnic Study of Atherosclerosis.

Chronobiology international·2026
See all related articles

Related Experiment Video

Updated: Feb 7, 2026

A Versatile Murine Model of Subcortical White Matter Stroke for the Study of Axonal Degeneration and White Matter Neurobiology
08:36

A Versatile Murine Model of Subcortical White Matter Stroke for the Study of Axonal Degeneration and White Matter Neurobiology

Published on: March 17, 2016

8.5K

School start times matter, eveningness does not.

Ignacio Estevan1, Ana Silva2, Bettina Tassino3

  • 1a Programa de Neuropsicología y Neurobiología, Facultad de Psicología , Universidad de la República , Montevideo , Uruguay.

Chronobiology International
|August 2, 2018
PubMed
Summary
This summary is machine-generated.

Eveningness, or later sleep-wake preferences, negatively impacts school grades for morning-shift students. This circadian timing effect on academic performance depends on school start times.

Keywords:
AdolescenceGPAMorningness–Evenignessschool shift

More Related Videos

Determining Soil-transmitted Helminth Infection Status and Physical Fitness of School-aged Children
10:57

Determining Soil-transmitted Helminth Infection Status and Physical Fitness of School-aged Children

Published on: August 22, 2012

24.4K
Production and Measurement of Organic Particulate Matter in a Flow Tube Reactor
13:29

Production and Measurement of Organic Particulate Matter in a Flow Tube Reactor

Published on: December 15, 2018

8.0K

Related Experiment Videos

Last Updated: Feb 7, 2026

A Versatile Murine Model of Subcortical White Matter Stroke for the Study of Axonal Degeneration and White Matter Neurobiology
08:36

A Versatile Murine Model of Subcortical White Matter Stroke for the Study of Axonal Degeneration and White Matter Neurobiology

Published on: March 17, 2016

8.5K
Determining Soil-transmitted Helminth Infection Status and Physical Fitness of School-aged Children
10:57

Determining Soil-transmitted Helminth Infection Status and Physical Fitness of School-aged Children

Published on: August 22, 2012

24.4K
Production and Measurement of Organic Particulate Matter in a Flow Tube Reactor
13:29

Production and Measurement of Organic Particulate Matter in a Flow Tube Reactor

Published on: December 15, 2018

8.0K

Area of Science:

  • Chronobiology
  • Educational Psychology

Background:

  • Morningness-Eveningness (M-E) chronotype influences academic performance, particularly when school activities are scheduled early.
  • Adolescent sleep patterns and school schedules often create a mismatch, potentially affecting learning.

Purpose of the Study:

  • To investigate the association between M-E chronotype and school performance in Uruguayan adolescents.
  • To determine if this association differs between morning and afternoon school shifts.

Main Methods:

  • A cross-sectional study involving 224 adolescents from a secondary school in Montevideo, Uruguay.
  • Data collection included socio-demographic information, academic grades, and M-E chronotype assessment.
  • Statistical analyses controlled for relevant confounding variables.

Main Results:

  • Afternoon-shift students generally displayed later circadian preferences (eveningness).
  • Eveningness was significantly associated with lower academic grades exclusively among morning-shift students.
  • No significant differences in socio-demographics or performance indicators were found between shifts initially.

Conclusions:

  • The impact of eveningness on adolescent academic performance is contingent upon the timing of school activities.
  • Aligning school schedules with students' natural circadian rhythms may be crucial for optimizing educational outcomes.