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Tree'ting Wood Better:Sunscreen for Trees
The purpose of this experiment is to determine whether or not wood can be used as an alternative testing method for sunscreens and which species of wood are good for this objective. This will be accomplished by applying varying strengths, or SPFs, of sunscreens onto thin wood veneers. They will then be exposed using a weatherometer, in which real light and sun conditions will be simulated. Using a device called a Pulmac, the samples of wood will be pulled apart from the centre at zero span. Based on the consistency of the strengths, it can be determined how the wood reacts to the sunscreen and whether that species of wood is suitable as a testing medium. Trees are an important commodity which enrich the lives of many people, particularly those who live in British Columbia. They provide the means of living and recreation for numerous people, whether it is employment, business, housing, or camping. Since trees are a renewable resource, they are convenient and realistic to use for testing. There are two possible extensions to this project. If the active ingredients in sunscreens can be determined, then we may be able to use these elements to create a new type of stain for fences and other structures. This could make the necessity for painting less frequent, creating cheaper options for the homeowner. The second possible extension of this project is to use the results to as an initiative to reduce the amount of animal and human testing done by manufacturers. This is important, as animal testing not only causes unnecessary pain, but often the results are not very accurate. Overall, I determined that this method of testing sunscreens would work quite well, especially with the following species, listed in decreasing order. 1) Yellow Cedar 2) Yellow Poplar 3) Maple 4) Hemlock These results were based on how tightly grouped together the means of the strength values were for each species. The closer they were, the more consistent that type of wood and therefore the better they are for testing. Overall, I think this method of testing sunscreens would work quite well, particularly with the yellow cedar, maple, yellow poplar and hemlock, as they resulted in fairly consistent strength values. Generally, the sunscreens with a high SPF, or Sun Protection Factor, resulted in a lower strength loss than the sunscreen with SPF 15. In addition to proving that sunscreen is a good method for preventing UV rays from reaching the skin, this experiment has also confirmed that there are other methods of testing sunscreens, which can be researched further. Along with my main presentation I will be showing various graphs, statistics, and pictures. They will be supplemented by a booklet of “Commonly Asked Questions and Answers” and species descriptions for each type of wood.
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溼地的勇士-海茄苳呼吸根與抗鹽逆境之研究
本研究觀察海茄苳四種呼吸根在形態學上的異同,並以顯微鏡觀察四種呼吸根的構造,\r 推論四種呼吸根的功能:出水呼吸根為露出土面吸收大氣中的氣體;纜狀根為支持植物本體\r 及運送由出水呼吸根吸收之氣體至植物本體;支持根為支持植物本體;營養根主要為吸收土\r 壤中的水分及養分。其次觀察海茄苳與其它植物葉片的構造、氣孔數量、氣孔型態、土壤的\r 差異並測量植物二氧化碳產生量,推論海茄苳需要呼吸根的原因為:一、葉片氣孔數量過少,\r 二、生長環境嚴酷不利於吸收養分及空氣,三、呼吸作用率較差。然後觀察海茄苳在不同濃\r 度鹽分的逆境下之泌鹽量、根部生長速率、葉片及根莖形態及存活天數。最後測量葉片表面\r 的導電度、內部電阻值及觀察有無老葉的方式,來推論海濱植物抗鹽分逆境的方法,發現:\r 一、海茄苳、海馬齒、馬氏濱藜可以泌鹽方式排鹽,二、林投、水筆仔等植物可以拒鹽方式\r 排鹽,(3)三、鹽定及海馬齒可以落葉方式排鹽。
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一、 什麼是噪音:噪音是聲音振動的不規律,音量很大時,聽了令人覺得不協調、不舒服、刺耳且煩躁不安。二、噪音對身體的危害:長期處在噪音環境下,不但易耳聾,且還會引發疾病影響生育功能或猝死。長期生活在 70 分貝至 80 分貝以上的環境中,可使人動脈收縮 、心跳加速、供血不足、出現血壓不穩、心律不整、心悸等症狀,甚至演變成冠心病,心絞痛、腦溢血及心肌梗塞。在噪音 80 分貝以上的環境中工作、學習,將使人精神無法集中、聽力下降,降低工作、學習效率。影響幼兒健康胎兒和幼兒的聽覺神經敏感脆弱,極易受噪音的破壞,嚴重時甚至會影響智力的發展。美國醫學專家研究指出,突發的強烈噪音,可使聽覺受到刺激,引起突發性的心律不整,使人猝死。三、預防噪音危害的生活保健:預防噪音先從不製造噪音著手.採消音建材綠化環境也有幫助。噪音是繼空氣污染、水源污染之後的第三大環境公害。
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中華民國第三十六屆中小學科學展覽-數學科評語
一、本年度數學科參展作品共五十七件,比往年略增,特別是國中組。許多作品,尤其國中、高中組多為學生自己討論出來的題目,而且作品品質顯著提昇,特別是國中組。 二、國小初小組部分作品顯示教師指導的比例偏高,題材跟往年略有重疊,惟學生對作品很有表達能力及成就感,初小教師應可加強輔導學生選題及相關資訊之搜尋,培養正確的參展態度及研究興趣。另外國小部分作品以實驗的方式呈現,但學生無法辨識數學實驗與自然科學實驗研究活動的特質,指導教師應該正確輔導。 三、國小高小組部分近年水準均佳,尤其或第一、二的兩件作品,顯示參展學生具超人一等的數學能力及空間想像力,值得培養繼續鼓勵,應為可造之才。 四、整體作品今年趨向於幾何與離散數學題材,似與參加國際數學競賽活動有關。取材適合學生本身能力,得獎作品探討細緻,部分作品已達國際科展選拔之水準,值得佳許。 五、部分作品屬長時間持續性的研究成果逐年增進作品內容,值得鼓勵。
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多多笛的發聲原理及各種因素對頻率之探討
多多笛的構造大致上可以分為內管、外管、孔洞和膜四個部分。它是藉由孔洞吹入氣體,氣體在內部流動,而造成膜的振動發出聲音。本實驗探討多多笛的發聲原理,了解是管子產生共鳴還是膜的振動影響聲音的頻率及探討哪些變因會影響多多笛的頻率。由於多多笛的外形構造複雜,於是我們用PVC管製作多多笛的模型,方便我們之後的研究。經實驗發現:多多笛發出的聲音頻率並不單純,當氣壓小時,它發出的頻率會越接近空氣柱共鳴,而不論氣壓大小,管長與頻率倒數皆呈正比關係,因此我們推測多多笛的發生機制是膜與空氣柱共振的結果,且經由分析,我們發現基音是符合閉管的基音,但是泛音皆為基音的連續整數倍,因此推測它產生的頻率是開管及閉管疊合而成。
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我們吃的食物包裝袋裡,常常可以看到乾燥劑的蹤影。乾燥劑對食物來說是非常重要的,不僅可以保存食物的風味,不至於變質,也可使食用期限變長;有些物品在潮濕的環境+也容易發霉,而影響其品質,例如:皮鞋、衣服、照相機…等等,也需要乾燥劑的保護。在老師的協助下我們利用書上學來的方法,將蛤蠣殼廢物利用,做成環保的乾燥劑;並使用受潮變化明顯的海苔,來證明蛤蠣殼製成的乾燥劑,的確有其效果。因為這些材料都是日常生活中隨手可得的,不需要太複雜的儀器,可見只要用心,科學就在你我的身邊。
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另類鋅銅電池---真正不需鹽橋、可充電的鋅銅電池
一般的化學電池除了兩個電極外,需要兩個燒杯內分別放入相關的電解質及一個鹽橋內放入一種可導電但不參與反應的電解質,實在是很不方便組裝,且電流又不大。例如傳統鋅銅電池正負電極分別為3×5cm2Cu片、3×5cm2Zn片,電解質[CuSO4]=0.4M、[ZnSO4]=0.4M,鹽橋[KNO3]=1.0M時,其電流約僅2~5mA、電壓約1.0V,且不可充電,此電池無論在裝置上、功能上都不是很好的設備。
經本實驗的結果顯示另類鋅銅電池有以下優點、特色:
1.當正負電極分別為銅的相關難溶鹽固體(CuO、Cu2O、CuS、CuCl)、3×5cm2Zn片時,僅需一種電解質,不僅鹽橋真的可以移除,無須半透膜、素瓷杯,在該電解質濃度仍為0.4M下,電流即可增加至70~100mA、電壓維持在約1.1V,且可充電!
2.銅的相關難溶鹽固體電極(CuO、Cu2O、CuS、CuCl)的製備方法---燒結法是考慮學校設備、經費下所獨創、可行的製備方法!這是高一基礎化學第一章第一節化學簡史中談論火的使用與容器製作的關係,加上日常生活中焢土窯的經驗讓我們突發奇想的作法。
3.目前此充電電池在0.4 M NaOH低濃度電解液下,電池未充電即自然放電可得70~20mA穩定電流,維持時間約10分鐘(600秒),經1~3次充電後,效能不僅可維持甚至更好,電流可達80~21mA,維持時間更拉長至28分鐘(1680秒)!所以無論是在實驗時的組裝便利性亦或電池的功能如電流大小、可充電性上,都有突破性的創新改善,應可作為將來國、高中的基本化學電池的實驗之一。
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台北市內湖金面山區兩棲爬行動物資源調查之研究
本研究之目的主要為調查臺北市內湖金面山區附近兩棲、爬行動物之物種概況,建立內湖地區的兩棲爬行動物基本生態資料庫,期望藉此研究可推行高中科學教育研究的基礎,並可充實自然生態保育與愛護鄉土心靈教育的實際教材。 調查研究工作是由2003年4月開始,至2004年5月為止,十四個月期間,總計85次的夜間野外觀察,已確認記錄兩棲爬行動物的種類共計有37種(分屬2綱3目13科24屬),蛙類:4科13種,蜥蜴類:4科9種,蛇類:4科13種,龜鱉類1科2種。 各物種總出現隻次方面,蛙類以拉都希氏蛙的1547隻次為最多,最少的是長腳赤蛙及斯文豪氏赤蛙,僅6隻次。蜥蜴類以黃口攀蜥的1995隻次最多,最少的為麗紋石龍子,僅4隻次;蛇類及龜鱉類以龜殼花最多,共計85隻次,而以梭德氏游蛇、大頭蛇、白梅花蛇、赤背松柏根、南蛇、盲蛇、食蛇龜及材棺龜等均只有1隻次為最少。 出現頻度方面,十四個月份中,蛙類的拉都希氏蛙及古氏赤蛙皆有出現,在85次的調查期間,則是以拉都希氏蛙的97.65%為最高,最少的為長腳赤蛙,只有3.53%;蜥蜴類的黃口攀蜥於十四個月份皆有出現,而在85次的調查期間,則有75次、97.65%最高出現頻度,麗紋石龍子於14個月份及85次的調查,出現頻度均是最低,各是21.43%及3.53%;蛇類及龜鱉類物種中,以龜殼花14個月及61次的出現記錄為最高,出現頻度分別是100%及71.76%;而食蛇龜及材棺龜均只有出現一個月及一次,故其出現頻度為7.14%及1.18%。 分佈廣度而言,於二十二個調查樣區中,蛙類以拉都希氏蛙的95.45%為最大,最小的為長腳赤蛙及斯文豪氏赤蛙的18.18%;蜥蜴類以黃口攀蜥的100%為最大,,最小的是無疣蜥虎的9.09%;蛇類則以龜殼花的86.36%為最大;龜鱉類物種皆僅4.55%的分佈廣度。 各樣區出現物種數方面,蛙類以A區的11種為最多,蜥蜴類以二期校區的7種為最多,蛇類是以AB區的9種為多;各樣區中,則是以AB區所發現的兩棲爬行動物物種數最多,合計共有22種物種。 由研究結果得知,調查樣區內的兩棲爬行動物物種歧異度大,其中蛙類的優勢物種為:拉都希氏蛙,蜥蜴的優勢物種為:黃口攀蜥,而龜殼花則為蛇類的優勢物種。而環境溫度的變化,與調查樣區內兩棲爬行動物出現活動的總物種數有顯著之相關性。 ;The goal of this research paper is mainly to investigate Taipei city, Neihu District, nearby Jin-Mian mountain’s amphibious and reptiles for the establishment of the lake area amphibious and reptile basic ecology information bank. It is hoped that this research will provide a foundation to further promulgate the high school science education and research, and may enrich the natural ecology protection and education materials for the loving care of local environment. The investigation started from April, 2003 to May, 2004, or for 14 months period and amounted to 85 times of field observations at night. It was confirmed that there were 37 species of amphibious and reptile ( 2 classes 3 aria 13 families 24genus),amphibious species: 4 families 13 species, lizard: 4 families 9 species, snake: 4 families 13 species, turtle: 1 family 2 species. In regard to the number of times of appearances, amphibious species of Rana latouchii had the most appearances with 1,547 times, and the least appearances was the Rana longicrus and the Rana swinhoana with only 6 times; for the lizards, Japalura polygonata xanthostoma had the most appearances with 1,995 times, and the least appearances was Eumeces elegans with only 4 times; for the snake and turtle, Trimeresurus mucrosquamatus had the most appearances with 85 times; for the Amphiesma sauteri sauteri, Boiga kraepelini, Lycodon ruhstrati ruhstrati, Oligodon formosanus, Ptyas mucosus, Ramphotyphlops braminus , Cistoclemmys flavomarginatn and Mauremys mutica , each had appeared only 1 time. On the appearance frequency, within the 14 months, amphibious species Rana latouchii and Rana kuhlii, Rana latouchii appreared 97.65%, the highest within the 85 investigations period, and the least was the Rana longicrus with only 3.53%; lizard Japalura polygonata xanthostoma had appeared within these 14 months, but in 85 investigations period, their frequency was 75 times, or 97.65% at the highest frequency. Eumeces elegans there upon within the 14 months and 85 investigations, had the lowest frequency each at 21.43% and 3.53%; for the snake and the turtle species, Trimeresurus mucrosquamatus within the 14 months and 61 appearances had the highest frequency record at 100% and 71.76%; but Cistoclemmys flavomarginata and Mauremys mutica only appeared once in a month and, therefore its frequency was at 7.14% and 1.18%. For the distribution breadth, in 22 investigation sample areas, amphibious species take Rana latouchii of the amphibious kind had the biggest record at 95.45%, and the smallest was Rana longicrus and Rana swinhoana at 18.18%; for the lizards, Japalura polygonata xanthostoma was 100% as the biggest, and the smallest was Hemidactylus bowringii at 9.09%; for the snake, the Trimeresurus mucrosquamatus was at 86.36% as the biggest; the turtle species had only 4.55% distribution breadths. For the number of appearance in each area, amphibious species in area A had the most with 11 species, lizard of second period school area had the most with 7 species, the snake of area AB had the most with 9 species. In all other areas, the amphibious reptile species number in area AB had the most with 22 kind of species. From the results of the research, the biodiversity of amphibious and reptile species within the investigation areas is very high, Rana latouchi is the codominant of Frog; Japalura polygonata xanthostoma is the codominant of Lizard, and Trimeresurus mucrosquamatus is the codominant of Snake.
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1. 遊戲規則:將1~ 2m × 2n的連續正整數,由上而下、由左而右依序填入 2m × 2n的方格內。操作規則允許將2m × 2n做往右或往左或往上或往下的完全對摺,直到操作至所有單位方格均疊成一行,此同時有數字也由上而下形成一數列。2. 本研究即是探討操作完成的數列之數量與數字間的關連性。3. 我們發現:(1) 數列之數量與巴斯卡三角形有關。(2) 形成的數列必符合內文的 [ R(L) 性質]、 [ D(U) 性質]、[ R&D 性質]、[D&R 性質]。
1. Rules of thegame: Fill in order the continuous positive integers 1~ 2m × 2n, from top to bottom and from left to right in the 2m × 2n check. The operational rule allows a complete fold of 2m × 2n either rightward or leftward, or upward or downward, until all the check units pile up in a line. At the same time, all the integers form a series from top to bottom. 2. This study explores the relationship between the number of the series and the integers after the operation. 3. Our findings are: (1) The number of the series is related to Pascal triangles. (2) The series formed meet the properties mentioned in the study: [the property of R(L)], [the property of D(U)], [the property of R & D], and [the property of D & R].
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本研究是為了改善擦黑板時粉灰任意飄散的情形,在使用一般板擦擦黑板時,粉灰累積到一定的量,會開始掉落而飄散到空氣中,影響使用者的健康,有鑑於此,改善此情形是本實驗的目標。「擦黑板時,如果能增加板擦的吸附能力,可以減少飄散在空氣中的粉灰」,為本組之最大目的。起初我們找了許多方法,而最後以靜電原理設計裝置,在不破壞板擦原型的前提下,利用電線導引靜電於板擦上。經過多次實驗證實,將裝置裝於板擦後,其吸附粉灰的量有明顯增加,確立了靜電板擦之可行性,達到了本組之目的。
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1.本研究將高中秒錶實驗的定性研究加以延伸,設計新流程以探討定量影響因素。預期目標為: (1)定義反應物的最初濃度與平均濃度,以①初期速率法與②微分迴歸法推導反應級數、速率常數。 (2)以③積分逼近法加以探究。 (3)由阿瑞尼士方程式推導活化能。 2.主要結論有四點: (1)以①、②法求出碘酸鉀的反應級數約為0.96~1.05級;亞硫酸氫鈉約為1.33~1.37級。不論採何法,高溫時所得速率常數較大。 (2)反應物的兩種濃度定義所獲結果,於反應級數無甚差異、但於速率常數則有差別。因此,反應物的濃度定義應明確區別。 (3)③法所得結果雖不精準,但由推導的過程深獲啟發。 (4)反應活化能約為8520 J /mol。 3.若實驗時數有限,可僅選做部分步驟,就可學習到三種數據分析的方法。
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線上教學資源
什麼是土石流?如何避免危險的土石流?
什麼是土石流? 土石流是快速塊體崩壞運動的一種,是水與泥沙、土石等固、液體混合後受重力下移而成的流動體。由於密度高,再加上沿陡高坡面或溪谷向下移動時,位能轉換成動能,加上能量大搬運力強,會不斷吞噬兩側鬆動的土石,因此雖然歷時短暫,但來勢兇猛,流速甚至可達每秒5公尺以上,產生強大的衝擊力,常在短時間內改變地表的形貌,沖毀或掩埋公路、橋樑、房舍、農田等各種設施,造成重大的災害。土石流發生的機制包括: (1)累積雨量250公厘以上或降雨強度每小時40公厘以上。 (2)地質條件不穩的山坡地,產生大量鬆碎的岩塊與沙土。 (3)略為傾斜的河谷,足夠的坡度才會因重力作用產生流動。 土石流的形貌在地形上可分為三個部分: (1)源頭區 河谷上游或源頭的山崩落石區,山勢陡峻,植被稀疏,岩層裸露,土石容易崩落堆積,常成碗狀或湯匙狀。 (2)流動區 河谷中下游,河床兩側有碎屑物,土石流由源頭產生後運動至此區,常合併此部份的土石,增加體積及能量後,破壞力增強。 (3)堆積區 位於河谷下游或出谷口處,坡度較緩,土石流物質堆積成。由源頭區、流動區至堆積區的整體形狀為伸長的舌狀。 如何避免危險的土石流? 台灣島位於板塊交接處,受到板塊擠壓影響,岩層破碎,而高溫多雨的氣候條件導致強烈的風化作用,歲列崩落的岩塊往往堆積於山溝溪谷,成為土石流的材料。再加上人為不當的山坡地開發與土地利用,砍伐具有水土保持功能的森林,更加強了土石流爆發的危機。減少土石流的災情,除了做好水土保持工程,在易發生土石流的山區溪谷裝設降雨警報裝置,另外,遠離容易發生土石流的地區,也是維護生命財產安全的必要作為。
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