Incorrect spelling, explanation: this word is a mistake since the correct spelling is particle. The correct form is a word part and suffix -cle (which gives a noun meaning). Partical is a wrong form, and it occurs possibly because of pronunciation, which may be misleading.

Correct spelling, explanation: this word was created from the word part and Latin suffix for nouns: -cle, giving the meaning of some small part, fragment. This origin explains why we spell the word particle like this, and not partical. This misspelling probably comes from pronunciation [pahr-ti-kuhl].

Definition of particle:
noun, a tiny fragment; usually in physics: a very small constituent of matter
There was no particle of evidence to his alibi.
To determine smoke density and particle size different wavelengths of light can be used.