Sun, Aug 19, 2007 - Page 14 News List

Sunday Science: Earthquake! 週日科學:地震!

By Catherine Thomas  /  STAFF WRITER



Welcome to Sunday Science! Every Sunday during the summer, we're going to guide you through some cool experiments that you can do at home. It's a good idea for you to keep a record of what you do in a Science Journal. That way you can record what you learn, compare results and maybe use them to design new experiments! Have a look at the Science Journal box for some ideas to get you started. Remember always ask a grown-up's permission before trying out an experiment.


Have you ever noticed that earthquakes feel differently depending on the type of building you are in at the time? Today's experiment will explain why.

What you will need:

A piece of cardboard (about 30cm by 16cm)

A sheet of construction paper (about 35cm by 50cm). If you don't have any construction paper, you can use stiff paper -- like the cover of a magazine.

Scotch tape

A straw

A ball bearing, BB or other small ball that will fit inside the straw


A 30cm ruler

A pen or pencil

- Using your ruler and pencil, divide the paper into five or six strips about 2.5cm wide. The longest strip should be about 50cm. The next should be 8cm shorter, and each succesive strip should be 8cm shorter than the last.

- Carefully cut up the paper so that you have five or six strips.

- Take each strip and tape the ends together to make a circle.

- Stick the circles onto the cardboard, just like in the picture.

- Take the straw and cut a piece 2.5cm long.

- Seal one end of the straw using Scotch tape and a scrap of paper (so that the inside end isn't sticky).

- Put the ball in the straw and seal the other end in the same non-sticky way.

- Attach the straw to the cardboard parallel to your circles.

- Shake the cardboard from side to side, keeping your hands level. Note how the different rings react. Start slowly and then speed up. Don't forget to record your observations in your Science Journal.











- 用尺和鉛筆將美工紙劃分成五或六條大約二點五公分寬的細長條。最長的細長條必須五十公分長,下一個長條短八公分,依此類推,接下去的每長條都陸續比上一長條短八公分。

- 小心地把紙裁成剛剛分好的五或六等份細長條。

- 拿起每一細長條並將兩端用膠掉貼起來,做成一個環狀物。

- 將這些環狀物依照圖示黏到硬紙板上。

- 拿起吸管並將它裁成二點五公分長。

- 將吸管的一端用膠帶和小紙片封起來。(如此一來,膠帶的內側才不會黏黏的。)

- 把小鋼珠塞進吸管裡,並且將吸管的另一端用相同的方法封好。

- 將你的吸管平行環狀物,固定在硬紙板上。

- 手保持水平,搖晃你的硬紙板。注意這些環狀物不同的變化。一開始搖慢一點,然後加快速度。別忘記將你的觀察紀錄到你的《科學日誌》裡。(翻譯︰泰德)

What's the Science? 科學原理

The ball hitting the end of the straw shows the frequency of the vibrations you are creating. The rings resonate at more than one frequency each. The largest ring begins to resonate first because it has the largest mass (and so it has a low resonant frequency) and because it is the least stiff of the rings (also giving it a low resonant frequency). An earthquake's frequency (and the direction) will affect how each building reacts. Of course, height is not the only factor. If a building is built well, then the "stiffness" will be increased, so lower frequencies don't affect it as much. So two buildings of the same height can have different reactions in an earthquake.


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