Waterproof & Transparency

防水性和透明度 · P3 Science
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🟢 Paragraph 1 · Waterproof 防水性
Some materials absorb water and allow water to pass through them, while others do not. Materials that do not absorb water at all are waterproof. Rubber, plastic, glass and metals do not absorb water and do not allow water to pass through them. They are waterproof materials. Fabric absorbs water and allows water to pass through it. It is not a waterproof material. However, fabric can be made waterproof by applying a layer of wax over it. A layer of wax helps make shoes waterproof.
有些材料会吸收水分并让水穿过,而有些则不会。完全不吸收水分的材料是防水的橡胶塑料玻璃金属不吸收水分,也不让水穿过,它们是防水材料。布料会吸收水分并让水穿过,它不是防水材料。不过,在布料上涂一层就可以让它变成防水的。涂上一层蜡可以让鞋子变得防水。
💡 下雨天的雨伞和雨衣为什么不会湿透?因为它们是用防水材料做的!试试往塑料袋上倒水,水会滑走不会被吸收。
🟢 Paragraph 2 · Transparency 透明度
The transparency of a material refers to how much light can pass through it. Some materials allow most light to pass through them. These materials are transparent. Glass and some plastics are transparent. You can clearly see objects placed behind transparent materials. Some materials allow only some light to pass through them. These materials are translucent. Frosted glass and some plastics are translucent. You cannot clearly see the objects placed behind translucent materials. Some materials do not allow any light to pass through them. These materials are opaque. Rubber, wood and metal are opaque materials. You cannot see objects placed behind opaque materials.
材料的透明度是指有多少光线可以穿过它。有些材料允许大部分光线穿过,这些材料是透明的玻璃和一些塑料是透明的,你可以清楚地看到透明材料后面的物体。有些材料只允许部分光线穿过,这些材料是半透明的磨砂玻璃和一些塑料是半透明的,你无法清楚地看到半透明材料后面的物体。有些材料完全不允许光线穿过,这些材料是不透明的橡胶木头金属是不透明的材料,你无法看到不透明材料后面的物体。
💡 做个小实验:拿一张白纸、一块玻璃和一本书,把手电筒照在它们后面。哪个能完全看穿(透明)?哪个只能看到一点光(半透明)?哪个完全看不见光(不透明)?
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