Sun, Sep 09, 2007 - Page 14 News List

Sunday Science: Fantastic plastic 周日科學:超棒的塑膠

fantastic plastic


This week we're going to make plastic at home. Impossible? No, but you will need some help from an adult as this experiment involves heating milk.

What you will need:



A pot (for heating the milk)

A teaspoon (for measuring)

Wax paper (a paper towel would work, too)

A cup (for measuring)

An empty jar

A sieve

- Ask an adult to help you with this experiment.

- Pour one cup of milk into the pot. Add two teaspoons of vinegar.

- Heat the mixture, stirring it often.

- When the mixture begins to boil, the milk will separate into curds and whey . When this has happened, remove it from the heat.

- Hold the sieve over a large bowl or pot. Carefully pour the mixture through the sieve. The curds will stay in the seive.

- Put the curds in the jar. Strain the leftover liquid to get any remaining curds. Add these to the jar.

- Add a teaspoon of vinegar to the curds. Leave for one to two hours.

- After one or two hours, strain the mixture from the jar. You can discard the liquid.

- Rinse the blob with water, and then knead it until it is the same consistency as bread dough.

- You can now mold your plastic into any shape you like. Leave it to dry on the wax paper. Make sure to leave it out of reach of pets and small children.

(Catherine Thomas, staff writer)










- 請大人幫忙你一起進行實驗。

- 先將一杯牛奶倒入鍋中,再加兩匙醋。

- 將混合液加熱,並時常攪拌。

- 開始沸騰時,牛奶將會分離成凝乳和乳漿,這種情形發生時就關火起鍋。

- 將篩子置於大碗上方,小心將混合液過篩倒入碗中,其中的凝乳就會留在篩子上。

- 將凝乳倒入瓶中,再將剩餘的混合液過濾一次以取得殘餘的凝乳,把它也倒入瓶中。

- 加一匙醋在凝乳中,先放置一至兩個小時。

- 一兩個小時以後,將瓶中混合物過濾,你可以把液體部分倒掉。

- 用水稍微沖洗這團物質,並將它揉捏成像做麵包的麵團那樣有彈性。

- 你可以將這團塑膠塑造成任何喜歡的形狀,再放在蠟紙上風乾,記得擺在寵物和兒童碰不到的地方。


Vocabulary 今日單字

1. wax paper n.

蠟紙 (la4 zhi3)

2. sieve n.

篩子 (shai1 zi5)

3. curd n.

凝乳 (ning2 ru3)

4. whey n.

乳漿 (ru3 jiang1)

5. strain v.t

過濾 (guo4 lu4)

6. discard v.t./v.i.

丟棄 (diu1 qi4)

7. consistency n.

堅硬度 (jian1 ying4 du4)

8. acrylic adj.

壓克力的 (ya1 ke4 li4 de5)

9. polymer n.

聚合物 (ju4 he2 wu4)

10. protein n.

蛋白質 (dan4 bai2 zhi2)

What's the science? 科學原理

Plastics are polymers. The polymer in milk is a protein called casein. When you add the vinegar to the milk, the acetic acid and the heat cause the milk to separate into curds and whey. The curds contain casein, fat and minerals. When the plastic is first made, it has the consistency of rubber and is easy to mold. After being left exposed to the air it hardens.





Science Journal 科學日誌

What do you know about plastic? What is it made from? What is it used for? Which household items do you think you could use to make plastic? What uses could you find for homemade plastic?


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