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【實驗指導】新版教科版小學科學四年級下冊2.6導體和絕緣體
實驗:借助電路檢測器來檢測物體的導電性。
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實驗目的:檢測物體的導電性。
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實驗材料:一個電路檢測器、回形針、橡皮、鑰匙、導線(芯)、木質鉛筆、鐵釘、粉筆、塑料尺、干樹枝、金屬紐扣、玻璃片、吸管、長尾夾、透明膠帶、鉛筆芯、磚塊、一元硬幣、瓷勺、泡沫塊、羽毛。
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實驗步驟:
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(1)用兩個檢測頭接觸要檢測物體的兩端，觀察小燈泡是否發光。
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(2)重復檢測兩次，并將檢測時小燈泡“亮”或“不亮”的情況記錄下來。（重復檢測兩次，是為了提高襝測的準確性，減少失誤）
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試驗現象：
實驗結論：回形針、鑰匙、導線(芯)、鐵釘、金屬紐扣、長尾夾、一元硬幣都是由金屬材料制成的物品，這類物品都容易使電流通過。鉛筆芯不是由金屬材料制成的，但它也可以使電流通過。橡皮、木質鉛筆、粉筆、塑料尺等都是由非金屬材料制成的物品，這類物品不容易使電流通過。
理解與應用
1.像銅絲那樣容易通過電流的物質，我們稱它們為導體。像電線外包著的塑料那樣不容易通過電流的物質，我們稱它們為絕緣體。
2.我們利用導體把電送到人們需要的地方，我們利用絕緣體阻止電流到人
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精煉反饋
1、如圖標出了制成鉛筆的幾種材料，通常條件下屬于絕緣體的是(?
?
?
?
?
)。
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A.木材、橡皮
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B.石墨、金屬
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C.不確定
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【答案】A
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【詳解】根據對選項進行分析，可知只有A中的木材和橡皮都是絕緣體，不善于導電。所以題目的答案為A。
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2、將下列各種物體連接在如圖所示的電路檢測器中，小燈泡不能夠發光的是（?
?
?
?
?
）。
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A.鐵釘
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B.回形針
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C.三角板
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【答案】C
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【詳解】根據對題意分析，可知用選項中的物體連接電路時，只有導體才能使小燈泡亮起來。分析選項，只有C選項的三角板是絕緣體，所以正確答案是C。
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