水的浮力(一)教學(xué)課件

··4cco周讓Valadononry.chAsposeslidesforNET4odientPEvaluationonly.CreatedwithAsposeSlidesforNET4.0dientProfilo71Copyright2019-2019AsposePtyL死海不死為什么淹寫不死他們?是神在保護(hù)他仉嗎浮力的來源?答案:水第一課時Valadononry.chAsposeslidesforNET4odientPEvaluationonly.CreatedwithAsposeSlidesforNET4.0dientProfilo71Copyright2019-2019AsposePtyL書一活動·空瓶壓入水中,手會明顯感受到向上的壓力·將手松開后,瓶子將迅速上升,然后浮出水面·結(jié)論:水中會上浮的物體受到向上的浮力。Valadononry.chAsposeslidesforNET4odientPEvaluationonly.CreatedwithAsposeSlidesforNET4.0dientProfilo71Copyright2019-2019AsposePtyL漂浮在水面的木塊,受到的浮力>重力???物體漂浮時受到的浮力=重力在水中會上浮的物體受到向上的浮力。那么,在水中會下沉的物體是否也受到水的浮力呢?Valadononry.chAsposeslidesforNET4odientPEvaluationonly.CreatedwithAsposeSlidesforNET4.0dientProfilo71Copyright2019-2019AsposePtyL彈簧測力器0彈簧2指針刻度盤秤鉤Valadononry.chAsposeslidesforNET4odientPEvaluationonly.CreatedwithAsposeSlidesforNET4.0dientProfilo71Copyright2019-2019AsposePtyL讀一讀02二01234514牛2.6牛3.6牛Valadononry.chAsposeslidesforNET4odientPEvaluationonly.CreatedwithAsposeSlidesforNET4.0dientProfilo71Copyright2019-2019AsposePtyL書【活動】P111、將物體掛在彈簧測力計(jì)下,記下彈簧測力計(jì)的讀數(shù)F12、再將物體浸入水中,記下彈簧測力計(jì)的讀數(shù)F23、比較彈簧測力計(jì)的讀數(shù)變化,你能得到什么結(jié)論?實(shí)驗(yàn)次數(shù)空氣中讀數(shù)F1(牛)水里讀數(shù)F2(牛)Valadononry.chAsposeslidesforNET4odientPEvaluationonly.CreatedwithAsposeSlidesforNET4.0dientProfilo71Copyright2019-2019AsposePtyL這個實(shí)驗(yàn)說明了什么2?在水中會下沉的物體也會受到水的浮力Valadononry.chAsposeslidesforNET4odientPEvaluationonly.CreatedwithAsposeSlidesforNET4.0dientProfilo71Copyright2019-2019AsposePtyL上述實(shí)驗(yàn)?zāi)艿玫揭环N用彈簧秤測浮力的方法?稱量法測浮力大小:彈黌秤兩次示數(shù)差浮=1條件:物體能沉入水中Valadononry.chAsposeslidesforNET4odientPEvaluationonly.CreatedwithAsposeSlidesforNET4.0dientProfilo71Copyright2019-2019AsposePtyL負(fù)式生習(xí)在空氣中用彈簧秤稱一物體重為15牛,把它浸沒在水中稱得重5牛,則它受到得浮力為10N牛;把它浸入一半時稱得重為10牛這時物體受到水的浮力為_5N牛.Valadononry.chAsposeslidesforNET4odientPEv