SCATTER, DISPERSE, DISSIPATE, DISPEL mean to cause to separate or break up.

SCATTER implies a force that drives parts or units irregularly in many directions.

e.g. the bowling ball scattered the pins

DISPERSE implies a wider separation and a complete breaking up of a mass or group.

e.g. police dispersed the crowd

DISSIPATE stresses complete disintegration or dissolution and final disappearance.

e.g. the fog was dissipated by the morning sun

DISPEL stresses a driving away or getting rid of as if by scattering.

e.g. an authoritative statement that dispelled all doubt

1. (with reference to a feeling or other intangible thing) disappear or cause to disappear:

〈雲･霧･煙･熱などが〉消散する; 〈効果･悲しみなどが〉消える; 〈集団などが〉解散する

e.g. no object : the concern she'd felt for him had wholly dissipated

〈雲･霧･煙など〉を消散させる, 追い払う; 〈熱など〉を逃がす; 〈恐怖･心配など〉を消す, 晴らす (!「群衆を追い散らす」の意味ではdisperseの方が普通)

e.g. with object : he wanted to dissipate his anger.

no object disperse or scatter:

e.g. the cloud of smoke dissipated.

2. with object squander or fritter away (money, energy, or resources):

｟非難して｠ 〈金銭･時間･精力など〉を浪費する; 使い果たす

e.g. he had dissipated his entire fortune.

Physics (usually be dissipated) cause (energy) to be lost, typically by converting it to heat:

e.g. no power is dissipated in this sort of control element.

dissipative |ˈdisəˌpādiv| adjective

dissipator |ˈdisəˌpādər| (also dissipater) noun

late Middle English: from Latin dissipat- ‘scattered’, from the verb dissipare, from dis- ‘apart, widely’ + supare ‘to throw’.