黑板

Multi tool use
黑板是能讓粉筆於上面標記的平面,通常用作書寫。
黑板可以是一塊漆了深色顏料(通常是深綠色或黑色)的板。黑板下方通常會有一個窄長的架,能放置粉筆和黑板擦。
黑板常用於教學。用沾了水的布或黑板擦(一塊帶氈的木,或一個用布捲成的物體)便可輕易去除粉筆跡。在濕的黑板上書寫,那些粉筆跡難以抹除。
优缺点
黑板的缺點在於使用時會產生不少塵埃(就粉筆的品質而定),有些人會因此而覺得不適,甚至引致呼吸困難。可是,其他顯示資訊的方法更昂貴且亦有不足之處,所以至今黑板在教室裡仍然被廣泛使用。但在一些地方,不會產生塵埃的白板開始漸漸取代黑板。
与白板相比,黑板有如下优势:
- 粉笔不需要额外养护;白板笔使用后需要盖上笔帽
- 相对于白板笔,粉笔的价格更低廉
- 粉笔气味温和;白板笔多有刺鼻气味
- 粉笔痕迹容易被清除;长时间留在白板上的字迹需要特殊溶剂擦除
- 织物上的粉笔可以轻易脱落;白板笔一般会对布料形成永久性染色
相關條目
外部連結
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维基共享资源中相关的多媒体资源:黑板
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规范控制 |
- GND: 4179987-2
- NARA: 10662872
- NDL: 00576002
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