歡迎閱讀《週日科學版》！我們每週日都要為你介紹可以在家中進行的有趣科學實驗。你可以在《科學日誌》中記錄自己做了哪些活動，這樣就可以將所學的紀錄下來，比較這些結果，也許還可以利用它們來設計新的實驗！先看一下《科學日誌》的點子再開始吧。展開實驗之前，記得要獲得大人許可喔！
This week we're going to experiment with objects to see which float and which sink. At the same time you can measure the volume of some of the objects. And finally there's a special trick that you can use to amaze your friends and family!
What you will need:
A measuring jug
PHOTO: CATHERINE THOMAS, TAIPEI TIMES
Water
Several household objects (make sure that they won't be ruined by being put in water!) For example a pencil, a ball, an eraser, an apple or a bottle of glue.
A boiled egg
A raw egg
A ping pong ball
A rubber ball
An orange
A piece of paper and a pen (to record your results)
A pair of tongs (optional)
A kitchen scale
▲ Before you start, make a table for your results. Down one side of the page write the name of the objects. Make four columns. Label the first column "prediction," label the second "result," label the third "volume," and label the fourth "mass."
▲ In the prediction column write "sink" or "float" depending on what you think the object will do.
▲ Place each item on the scale and weigh it. Write the mass (weight) in the mass column.
▲ Carefully place each object, one by one, in the water. If you like you can use the tongs to help you put the objects in the water without splashing.
▲ After you place each object in the water, write "sink" or "float" in the result column.
▲ If an object sinks you can measure its volume. Take the object back out. Check that the water level is exactly on the 3/4 mark, if necessary top it up.
▲ Place the object back in the water. Be careful not to let the water splash out of the jug.
▲ Check where the water level is. Write the number (a) down. Now write down the number at the 3/4 mark (b).
▲ Now subtract (b) from (a).
(a) - (b) = volume of the object.
Don't forget to record what happens in your Science Journal.(catherine Thomas, staff writer)
本週我們要用一些物體來實驗，看哪些會漂在水上，哪些會沉入水裡。同時，你可藉此測量一些物體的體積。最後，我們還要教你一種可以讓朋友和家人大感驚奇的特別把戲。
所需材料︰
一個量杯
水
若干家用物品（確定這些東西碰到水不會壞！）例如：鉛筆、球、橡皮擦、蘋果、一瓶膠水
一顆煮熟的蛋
一顆生蛋
一顆乒乓球
一個橡皮球
一顆柳丁
一組紙筆（記錄結果用）
鉗子（可有可無）
廚房用磅秤
▲開始前，先畫一張記錄結果用的表格，在紙張的一邊寫上物品的名稱後，在表格上畫出四行欄位，註明第一欄為「結果預測」，第二欄為「結果」，第三欄為「體積」，第四欄為「質量」。
▲在「結果預測」欄寫下你認為這個物體會「下沉」或「浮起」。
▲用廚房磅秤測量各物體重量後，在「質量」欄記下質量（重量）。
▲小心地將物體個別放入水中，一個放完後再放另一個。如果你喜歡，也可以用鉗子協助把物體放至水中，避免濺起水花。
▲把每個物體都放入水中後，在表格的結果欄填入「下沉」或「浮起」。
▲你可以測量出下沉物品的體積，先將物品取出，確認量杯中的水位剛好在四分之三杯刻度高，若水不夠多，把水加足。
▲把物品放回水中，小心不要讓水濺出。
▲檢查量杯的水位刻度，記下數據(a)，再記下四分之三杯處的刻度數據(b)。
▲用數據(a)減數據(b)。
(a)-(b)就等於該物品的體積。
別忘了在《科學日誌》中記錄結果。（翻譯：袁星塵）
What's the science? 科學原理
When you put an object in water gravity is trying to pull it downwards, but the water is trying to push it upwards (upthrust). Water has a density of approximately 1g/ml. If an object is more dense than water then it will sink (gravity will win). If an object is less dense than water then it will float. Density is calculated using the mass (weight) and volume of an object: (density = mass/volume). If an object sinks you can measure its volume. Can you think of a way to measure the volume of the items that don't sink? In this experiment you can see which objects are more dense than water (the ones that sink) and which are less dense than water (the ones that float). The orange: The orange peel contains lots of pockets of air. This makes the peel less dense than water and so it floats (and makes the whole orange float). When you take away the peel you take away the air and so the fruit (which is filled with juice) sinks. So even though you have removed mass from the orange the density has increased.
當你將物體放入水中，重力會吸引它下沉，但水則會把它往上推（衝上）。水的密度約為每毫升一公克，若物體的密度大於水的密度，它就會沉入水中（重力勝利）；若物體密度小於水的密度，它就會浮在水上。密度是用物體的質量（重量）和體積計算出來的（密度=質量÷體積）。若物體下沉，你可以測量出它的體積。你可以想出一個方法來測量漂浮物體的體積嗎？這個實驗可以讓我們看出哪些物體的密度大於水（下沉的物體），以及哪些物體的密度小於水（浮起的物體）。柳丁把戲：柳丁皮中有許多的氣孔，使得柳丁皮的密度小於水，因此才浮於水上（也使得整顆柳丁浮起）。當你將柳丁去皮後，你除掉了空氣，因此（充滿汁液的）果實下沉。因此，即使你讓柳丁的質量變輕，但它的密度卻增加了。
Photographer Franziska Stuenkel likes to take spontaneous urban shots, so she needs a nimble camera that is ready to go when inspiration strikes: her German-made Leica M11. “I have to be very quick and discreet,” said the Berlin-based artist who captures reflections of people walking past windows, their contours merging with the shapes behind the glass. Stuenkel’s compact Leica is the perfect camera for the job, the 51-year-old told AFP. Famous for its pocket-sized and retro-style devices, the Leica brand is celebrating a milestone as it marks 100 years since its first commercial camera was presented to the public. The
Picture a 45-foot-long animal with a 5-foot-long skull and 3-foot-long arms. It may not seem strange until you realize that a human with those proportions would be 6 feet tall with 5-inch arms. Although the Tyrannosaurus rex went extinct 65 million years ago, the mystery of its unusual body __1__ has fascinated scientists for over a century. Barnum Brown, the paleontologist who first discovered T. rex fossils, initially found it hard to believe that the tiny arms belonged to such a __2__ creature. One of his colleagues speculated that the short forelimbs might have been used to hold the
Dogs’ noses are incredibly keen. They can even detect changes in cortisol levels in human sweat and breath. Known as the “stress hormone,” cortisol increases when humans are under pressure. Recent research indicates that the smell of human stress can influence a dog’s behavior and emotions. In the study, human volunteers were exposed to the stressful tasks of preparing and delivering a speech on the spot and then solving math problems. __1__ Researchers collected sweat and breath samples from the volunteers on pieces of cloth during both their stressful and restful states. Meanwhile, other researchers worked with 18
1. 錢已經用一半了。 ˇ Half of the money is gone. χ Half of the money are gone. 註：Half of ... 作主詞時，動詞與介詞 of 後面的名詞或代名詞相一致，即名詞或代名詞是單數時，動詞該是單數；若為複數，則動詞也該是複數，例如： Half of the story is interesting. Half of the stories are interesting. Half of it is interesting. Half of them are interesting. 2. 許多人走過這條路。 ˇ Many a man has travelled this road. χ Many a man have travelled this road. 註：many a 意義上雖然作 many 解，但後面應跟單數名詞，動詞也用單數形式。 3. 敵人被迫投降。 ˇ The enemy were forced to surrender. χ The enemy was forced to surrender. 註：enemy 作為總稱，前面須有定冠詞，用作句子主詞時，動詞通常用複數形。類似的情形如 talent： Taiwan is known for its semiconductor technology and is actively working to attract and retain global talent. 4. 他倆誰都不該責怪。 ˇ Neither of them is to blame. χ
RSS