molecule

«molecule» in Mova's school dictionary: the smallest unit of a substance that still has its… — its meaning for a pupil, its sense in the lessons and examples, with 5 sentences of Mova's corpora that use it.

part of speech

noun (a molecule, molecules)

meaning for a pupil

1) A molecule is the smallest unit of a substance that still has its properties, made of two or more atoms joined together. tree →

2) A water molecule, for example, is two hydrogen atoms joined to one oxygen atom (H2O). tree →

sense in the lessons

In science lessons molecules come up in states of matter: in solids molecules are packed tightly and vibrate, in liquids they slide past each other, in gases they move fast and far apart; heating makes them move faster. Pupils learn formulas like H2O (water), CO2 (carbon dioxide) and O2 (oxygen). Molecules are much too small to see, even with an ordinary microscope.

examples

• A water molecule has three atoms. tree →
• When ice melts, its molecules start to move more freely. tree →
• Oxygen gas is made of molecules with two oxygen atoms. tree →
• Smells reach your nose as tiny molecules floating in the air. tree →
• Heating makes molecules move faster. tree →
• Carbon dioxide molecules are breathed out by animals. tree →
• A single drop of water has more molecules than there are stars we can see. tree →

note

Plural «molecules». Say «MOL-ih-kyool». Adjective «molecular». An atom is a single particle of an element; a molecule is atoms joined together. Not all substances are made of molecules (metals and salt are made differently), but at primary level «particles» is often used for all of them.

In the corpora

• Atoms rarely stay alone: they join up into groups called molecules, a bit like Lego bricks clicking together.
• "H2O" means two hydrogen atoms joined to one oxygen atom: that is one molecule of water.
• Our noses sense particular molecules; natural gas has no smell, so companies add a smelly chemical to make leaks noticeable.
• Carbon atoms can link into long chains and rings, which is how huge molecules like sugar, wood and DNA are built.
• Melting, freezing, boiling and condensing are reversible changes, because the molecules stay the same.

Trees and pragmatics

Every meaning and example of «molecule» parsed by Mova, each sentence with its dependency tree and frames.