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Mai Lam
11-11-2007, 06:43 PM
Make a Hollow Penny
This is an easy chemistry project that uses common materials. You take a post-1982 penny, score the copper surface to expose the zinc interior, react the zinc with acid, and are left with a hollow copper penny.

Hollow Penny Materials

* post-1982 pennies (the composition of pennies was changed when the copper became more valuable than the currency)
* muriatic acid (from a hardware store)
* a disposable plastic container or glass jar
* baking soda
* water

Make Hollow Pennies

* You need to expose the interior of the pennies. You can score the edge of the pennies with a file or snip them with wire cutters, but I think the easiest way to expose the zinc is to rub the edge of each penny along a brick or concrete block. You could use sandpaper, if it's available. Use whatever is handy to expose some of the zinc (don't go all the way around the coin). If you can see silver metal under the copper of the penny, you're ready to proceed to the next step.

* It's best to do this step outdoors or under a fume hood, wearing gloves and protective eyewear. Read the safety precautions on the muriatic acid container. Basically, this is hydrochloric acid. Treat it with respect. Place the pennies in your container. Pour a little muriatic acid over the pennies so that they are covered. Bubbles will start to form immediately. Set the container somewhere where it will be safe from spills, children, and pets. Let the reaction proceed for about 6 hours.

* Carefully pour off the muriatic acid. You can wash it down a drain, providing you use a lot of water.

* Fill the container with water. Add a little baking soda to neutralize the residual acid.

* Examine your penny. The hollow penny will be a fragile copper foil.

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Thank you:)

Mai Lam
15-11-2007, 11:01 AM
:( sao khng ai dịch gim em vy. Cc anh chị lm ơn với, đoạn ny kh qu h :(

hbae787
15-11-2007, 10:58 PM
Make a Hollow Penny
This is an easy chemistry project that uses common materials. You take a post-1982 penny, score the copper surface to expose the zinc interior, react the zinc with acid, and are left with a hollow copper penny.
Lm một đồng xu rỗng
Đy l một bi thực tập ha rất dễ, dng cc vật liệu thng thường. Lấy một đồng xu penny đc sau năm 1982, cạo mặt đồng để lộ lớp kẽm bn trong, cho phản ứng với a-xt. (Khi ruột kẽm bị a-xt ha tan) n lm thnh một đồng xu rỗng bn trong.

Hollow Penny Materials
Vật liệu
* post-1982 pennies (the composition of pennies was changed when the copper became more valuable than the currency)
* muriatic acid (from a hardware store)
* a disposable plastic container or glass jar
* baking soda
* water
* vi đồng xu đc sau năm 1982 (từ năm ny, gi đồng tăng cho nn lượng đồng dng để đc 1 xu cn đắt hơn gi trị của 1 xu)
* a-xt muriatic (mua ở tiệm đồ sắt/mộc)
* 1 bnh nhựa hay thủy tinh
* Bột nở bi-cc-b-nt
* nước

Make Hollow Pennies
Cch lm
* You need to expose the interior of the pennies. You can score the edge of the pennies with a file or snip them with wire cutters, but I think the easiest way to expose the zinc is to rub the edge of each penny along a brick or concrete block. You could use sandpaper, if it's available. Use whatever is handy to expose some of the zinc (don't go all the way around the coin). If you can see silver metal under the copper of the penny, you're ready to proceed to the next step.
* Phải lm lộ phần bn trong đồng xu. C thể nạo cạnh đồng xu bằng dũa hay cắt bằng ko cắt sắt; nhưng c lẽ cch dễ nhất l mi mặt đồng xu vo cục gạch hay xi măng. C thể dng giấy nhm, nếu c sẵn. Dng g cũng được miễn l lm lộ ra lớp kẽm (đừng mi hết cả ton bộ cạnh). Khi trng thấy mầu xm bạc dưới lớp đồng l chuẩn bị sang bước hai.

* It's best to do this step outdoors or under a fume hood, wearing gloves and protective eyewear. Read the safety precautions on the muriatic acid container. Basically, this is hydrochloric acid. Treat it with respect. Place the pennies in your container. Pour a little muriatic acid over the pennies so that they are covered. Bubbles will start to form immediately. Set the container somewhere where it will be safe from spills, children, and pets. Let the reaction proceed for about 6 hours.
* Tốt nhất nn lm bước ny ngoi trời hay dưới quạt ht hơi khi. Nn đeo găng tay v knh bảo hộ. Đọc kỹ phần an ton sử dụng trn chai a-xt. Thường đy l a-xit clor-hydric. Phải nn thận trọng. Đặt đồng xu vo bnh nhựa. Đổ a-xt ngập đồng xu. Bọt hiện ra ngay. Cất bnh ở một chỗ an ton trnh đổ vi, trẻ con, v ch mo trong nh. Để phản ứng ha học a-xit ăn mn kẽm xảy ra khoảng 6 tiếng.

* Carefully pour off the muriatic acid. You can wash it down a drain, providing you use a lot of water.
* Cẩn thận gạn a-xt ra. C thể đổ xuống rnh thot, nhớ mở vi nước trng kỹ.
* Fill the container with water. Add a little baking soda to neutralize the residual acid.
* Đổ nước vo bnh. Cho một t bột nở bi-cc-b-nt vo để trung ha lượng a-xt cn st.
* Examine your penny. The hollow penny will be a fragile copper foil.
* Cầm đồng xu ln m quan st. By giờ n biến thnh một lớp "giấy" bằng đồng, mỏng dnh.