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How do the sigma bond and pi bond contribute to a carbon-oxygen double bond?

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oxidation of alcohols — aldehyde Alcohols may be oxidized to give aldehydes, ketones, and carboxylic acids. The oxidation of organic compounds generally increases the number of bonds from carbon to oxygen, and it may decrease the number of bonds to hydrogen.

In the carbonyl group found in aldehydes, the carbon-oxygen double bond is composed of two distinct types of bonds:

Sigma ( $σ$ ) bond: The electron pair of this bond is located directly between the bonded carbon and oxygen atoms.12
Pi ( $π$ ) bond: The electron pair of this bond occupies space on both sides of the $σ$ bond.12

The presence of the $π$ bond allows the carbonyl group to participate in addition reactions, as this bond can be broken to form new $σ$ bonds with other species. Unlike the nonpolar double bonds found in alkenes, the carbon-oxygen double bond is inherently polar because the electrons are drawn more strongly toward the oxygen atom than the carbon atom, creating partial charges.123