molecule

Everyday

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 →

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 Jewish tradition

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.

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.