This week we're going to try a really cool experiment that will make a great gift, too. We're going to make rainbow flowers. Why not make one for your teacher for Teacher's Day?
What you will need:
A fairly wide straw
A white flower. Roses or
carnations work best.
Sticky tape
Food coloring (as many
different colors as you
can get)
A bowl, or the bottom half of a
big water bottle
Scissors
A utility knife (ask an adult for help)
A pipette or small sugar spoon
- For the fastest results, leave your flower out of water for a couple of hours before you begin.
- First of all, put down some newspaper and make sure that you are wearing suitable clothes. This experiment can get messy, and you'll be using food dye.
- Cut the straw into four equal pieces.
- Take a section of straw at a time. Fold the last half centimeter of the straw back on itself to seal one end of the straw. Secure it with sticky tape. Repeat with the other three sections.
- Put the four sections together so that they are all touching each other, just like in the photo. Secure them with sticky tape. Now you have a holder.
- Put the holder in a place where it can stand upright, for example in a small box.
- Carefully add different color food coloring into each straw. Be careful not to accidently mix your colors. However, do think about, for example, making a purple by mixing red and blue dye in the same straw. You can use the pippette or sugar spoon to help you measure out the dye if it doesn't have a drop cap. Each straw should be about 3/4 full.
- Ask a grown-up to hold the flower stem under water and snip the end of the flower stem diagonally. A shorter stem will produce faster results.
- Ask the grown-up to split the bottom 5cm of the stem into four equal parts lengthwise, using the utility knife.
- Very carefully put each of the four split ends into a different straw in your holder.
- Wait and watch. Your flower will start to change color in as little as 20 minutes. Keep checking on it. After about two hours it should be fully colored. You can choose to leave it in the dye overnight to see if it changes again, or you can now put it in water.
(Catherine Thomas, staff writer)
本週我們要做一個非常酷的實驗，成品也可以當作一個非常特別的禮物喔。我們要做的是「彩虹花」。你可以親手做一朵送給你的老師，當作今年教師節禮物。
所需材料︰
一支夠粗的吸管
一朵白色的花，玫瑰或康乃馨效果最佳。
膠帶
食用色素（越多顏色越好）
一個碗，或大寶特瓶的下半節
剪刀
一把美工刀（一定要請大人幫忙）
一個滴管或一個小糖匙
- 如果想要在最短時間內看到成果，在開始之前，先將你的花拿出水瓶靜置幾個小時。
- 首先，先舖一層報紙，並穿上不怕弄髒的衣服。因為你等會兒會用到食用色素，所以這個實驗可能會弄得有點髒亂。
- 將準備好的吸管剪成等長的四段。
- 一次拿一段吸管。將吸管的尾端反折０．５公分，讓一端呈現密封狀態，再用膠帶將折起的部份固定好。其餘三段吸管也重複這個動作。
- 就像照片裡那樣，將這四段吸管併攏靠在一起，再用膠帶將它們黏牢。現在，我們完成了支架的部份。
- 將這個支架放在一個可以直立不會倒的地方，例如放在一個小盒子中。
- 小心地將不同顏色的食用色素加入四段吸管。請注意別將顏色混在一起囉。但是你可以考慮看看用兩種不一樣的顏色創造出一個新的顏色，例如試著將紅色和藍色加入同一支吸管，就會得到紫色喔。如果你買的食用色素沒有滴頭的話，你可以用實驗滴管或糖匙幫忙。每一段吸管應裝滿約四分之三。
- 請一個大人幫你將花梗放在水中，然後斜斜地剪掉下面的莖。莖較短可以更快看到結果。
- 請大人用美工刀幫你把花梗的末五公分縱向切開成四等份。
- 非常小心地把切好的四份花梗插入支架中四段吸管。
- 等著看會有什麼變化。二十分鐘後，你的花會開始變色。持續注意觀察，約莫兩小時後，你的白花應該已經轉變為一朵五彩繽紛的彩虹花了。你可以選擇讓它留在染料中過夜，然後隔天再看看是否還有變化。或者，你也可以把這朵美麗的彩虹花放到一般水中了。
（翻譯：袁星塵）
What's the science? 科學原理
Water evaporates from the petals and leaves of the flower. This is called transpiration. The flower needs to replace the water, so it sucks up the dye from the straws and sends it to where the water would be. The stem holds much smaller tubes, called vascular bundles. Because you have split the stem, each dye color travels up different vascular bundles in the stem and reaches different parts of the flower. The whole process is called capillary action.
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