終端速度
液體中之球體運動與液體的黏滯性有關,本實驗找出球體半徑與終端速度之間的關係。利用攝錄機作為紀錄工具,拍攝三種材質(壓克力、玻璃、水晶)的球體在沙拉油中的自由落體過程。使用電腦影像處理軟體將影像分解成幅影像,時間的解析度為1/30秒。測量球體的高度與時間,分析高度與時間的變化情形,發現終端速度與球體半徑之間的關係。
流體中之運動方程Fdrag = -k1V,無法符合實驗結果。我們的實驗結果顯示油中的自由落體的運動方程應該是Fdrag = -(k1V+ k2V2)。由不同材質的壓克力球(~1.18g/cm3)、玻璃珠(~2.47g/cm3)與水晶球(~2.66g/cm3)所獲得的終端速度(Vt)與球體半徑(a)的關係為a3(ρ-ρ') = 0.00003(a Vt)2 + 0.00021(a Vt) + 0.00575,其中ρ與ρ'分別為球體密度與沙拉油密度(0.90 g/cm3)。
再者,在相同半徑的條件下,密度越大的球體終端速度越大,在靜止下落後,越久達到終端速度。
The motion of a sphere which is falling through a fluid is subject to the fluid viscosity. In this study, we find out the relation between the radius of a sphere and the terminal velocity. We used a digital camera to record the sphere's descent in the oil. The three kinds of sphere we choose are acrylic(~1.18g/cm3), glass (~2.47g/cm3)and crystal (~2.66g/cm3). Frame-by-frame analysis of the video footage yielded rough estimates of the sphere's location within 1/30 seconds accuracy for statistically consistent results. By measuring the location and time and analyzing them, we find out the relation between the radius of a sphere and the terminal velocity. The expression of the drag force,Fdrag = -k1V, is not cosistent with our results. The study indicates the expression of the drag force should be Fdrag = -(k1V+ k2V2). The expression for the terminal velocities of the three kinds of sphere is of the form:a3(ρ-ρ') = 0.00003(a Vt)2 + 0.00021(a Vt)+ 0.00575, where a is the radius, ρ is the sphere density and ρ' is the oil density(0.90 g/cm3). In addition, if the radius is the same, the terminal velocity of a denser sphere is higher and the time to approches the terminal velocity is longer.
水分子自我組裝之機制探討
Up to this time we have spent almost three years in studying condensation and water droplets. Little could we have done as compared with the almighty nature. However we are rewarded by the nature as we gradually found the secrets about electro-magneto field and water droplets: The size of water droplets turn smaller upon electro-magneto field and grow more uniformly especially upon electric field. This experiment presented here is actually the diary of the growth of water droplets in condensation, upon magnetic field and electric field. Through convection, it discusses the self assembly patterns of water droplets and peep into the uniformity both of the size and the distribution mode of water droplets. In former basic experiment, we focus on temperature and the speed of water moisture; generally speaking, higher temperature speeds up the coalescence procedure but does not affects the nucleation size of water droplets in simple plain surroundings; while speed of moisture does affects the nucleation size. As we went farther, deep into convection and found magneto-electric force did play an important role in the self assembly mechanism of water droplets. The topic is mostly concerned as we are surrounded by magneto-electric waves in today’s world. This experiment anchors the first step in discovering the uniformity of water droplets in different environment, and providing insights into the self assembly mechanism of water droplets upon electro-magneto field with nano sizes. 這是一系列關於水蒸氣冷凝為極細微小水珠的實驗。其中可以分為兩大部分; 第一部分是基礎實驗。將水蒸氣導入至潔淨的介面上(蓋玻片),觀察冷凝水珠的結構。雖然看似簡單平常,但卻有令人驚奇的發現;不同溫度的水蒸氣,其冷凝最初始的細微顆粒之尺寸是相同的 !爾後隨著溫度的升高,堆疊速率也跟著上升;以致於最後一起呈現出來的水珠大小不一,尺寸不一。 第二部分是將水蒸氣導到磁場及靜電場上,觀察其冷凝結構。這部分的實驗推翻了一般「水分子是電中性在電磁場中不受影響?」的刻板觀念 !實驗所呈現出來的冷凝水珠,不但於附加磁場中尺寸縮小又不易長大,同時還有固定的自我組成模式( Slef-assembly pattern);而且也發現在磁場中的冷凝小水珠的尺寸比電場中的小,可是電場中的小水珠則表現出較大的均勻特質。
昆蟲也會大小眼!?
本研究目的主要在瞭解昆蟲的複眼(compound eyes)結構,比較晝行性與夜行性昆蟲複眼之差異,探討其視覺遠近和複眼結構的關連,及進一步觀察其對不同波長光源反應的差異。本實驗使用反射式及倒立式顯微鏡來觀察複眼及其小眼的結構,及觀察其成像情形,並使用攝影式接觸分析儀與放大管來探討視覺遠近和小眼表面曲率之關連,另外在暗室利用不同波長的光源照射蝴蝶以觀察其反應。實驗結果顯示複眼是由數千至數萬個小眼組成,小眼表面曲率半徑隨選用物種在25.3μm 至117.6μm 之間,蜻蜓複眼上半部和下半部小眼曲率半徑分別為30.6μm、117.6μm,印證了蜻蜓複眼上看遠下看近的說法,也發現蝦子小眼是正方形,其他實驗物種則皆為六邊形,而蝴蝶對光的反應程度則是隨波長漸增而遞減。The main purpose of this study is to understand the structure of the compound eye of insects, to compare the difference between the diurnal insect’s compound eye (apposition eye) and that of the nocturnal insect (superposition eye), to explore the relationship between the vision and the structure of the compound eye, and to observe the eye’s reaction to the different light wave length. In this study, a microscope (OLYMPUS BX51M) and an inverted microscope (OLYMPUS 1X71) were used to observe the structure of the compound eye and its ommatidia, as well as the resulting image. A contact angle measuring instrument (Dataphyscis OCA 20) and a microscope (Mitutoyo NAVITAR) were used to determine the connection between the vision distance and the facet curvature of ommatidia. The butterfly’s reaction to the light source with different wave length was also observed in a darkroom. It was observed that the compound eye of insects is composed of more than a thousand ommatidia. Among the subject insects, the facet curvature radius of their ommatidia ranged from 25.3μm to 117.6μm. The radius of the top and bottom half of a dragonfly is 30.6μm and 117.6μm. It confirms a scientific finding that dragonfly’s top compound eye focuses farther than the bottom half. The facet of each ommatidium observed is hexagonal in insects compared with the square shape found in the eye structure of shrimp. Regarding the reaction to light of the butterfly eye; the reaction decreased when the light wave length increased.
擺動知覺曉,觸角知多少!--光線與震動影響美洲蜚蠊觸角擺動模式之研究
During the biology classes from junior to senior high, we have learned many interesting instance of different animal behavior. Most people paid more attention on the Vertebrates as their experimental subjects. The other species around us, although with simple body structures, may behave rather complicated and versatile reactions. In particular, one of the most common insects with simple body structure in our neighborhood is the American cockroach (Periplaneta americana). The aim of this study is to investigate the different swing motion modes of antennae of American cockroach by computer-aided Imaging Analysis. The parameters of each swing motion mode were calculated in order to analyze how light (including light stimulation and light adaptation) and vibration may affect the antennae behavior of American cockroach. It was found that the antennae swing motion modes were significantly different under different types of stimulus. If two types of stimulus occurred at the same time, the reactions of antennae motion may become conformable. In conclusion, antennae behavior has shown to significantly affect the survivability and environmental adaptation of American cockroach. Not only the antennae are considered as the sensitive receivers; but also they are the important transmitters to reflect physiological status and environmental condition.從國中到高中的生物課堂上,我們學到許多有趣的動物行為例子,但前人多以脊椎動物作為研究對象,而我們身旁的許多生物,身體構造雖較為簡單,但行為表現卻豐富多樣,尤其是常見的美洲蟑螂(Periplaneta americana),可說是最親近我們的昆蟲之一。本研究以攝影紀錄的方式,透過電腦進行影像分析,記錄不同刺激下蟑螂的觸角擺動模式,並計算出各項觸角運動的參數,以瞭解光線(照光刺激或照光適應)與震動刺激對其觸角行為的影響。我們發現在不同因子的刺激下,觸角擺動的模式具有差異,若兩種刺激同時發生,蟑螂觸角的行為亦具有整合性的反應,證明蟑螂觸角的行為模式,對其生存與適應具有重要意義。這也代表觸角除了為敏感的受器,亦為能反映出生理與環境狀態的重要動器。
天空之城耐震設計與隔震技術之探討
我們的研究包括兩部份,第一部份是實地調查訪問。瞭解地震成因、傷害及現有防震方法,並調查坊間各種建築物類型,及常見私自改變建築物結構現象,做為研究的基礎。第二部份為建築物抗震實驗。研究發現:牆面挖空、頂樓加蓋、樓層挑高,建築物會在該處產生弱點,由此斷裂。柱子數量相同下,散開時支撐力較弱。不對稱建築物遇震時會不自然扭轉且易倒。隔震素材恰當,能有效提高耐震力。滑軌、彈珠隔震效果很好,但位移太大,為實際建築所不容許。建物下加裝阻尼材料,能吸收部份地震能量,降低地震對建築物的危害,並有效控制位移問題,是良好的隔震素材。樓頂加裝消能設施亦能減震,但設計極其不易。 The research includes two parts. In the first part the work is concentrated on on-site visiting and investigation such as understanding the cause of earthquake, the damage and the preventive method currently available, investigating the different types of building and the phenomenon of altering the structure of an existing building without permission by government authorities which is popularly seen in Taiwan. These are considered as the basis of the research. The second part is the experimental study of earthquake resistance of a building. The test results showed that weak-point can be caused at the place where the existing wall is moved or an extra building is attached to the roof or the structure of building has extended space between floors, and fracture always occurs at the weak-point. If the number of columns of a building is the same, then the scattering arranged location of columns is weaker than concentrating type of arrangement of columns. The building having unsymmetrical structure will twist in uneven fashion that causes the building apt to collapse in case of earthquake. Employing proper vibration-absorption material can effectively increase earthquake resistance. Sliding rails and balls can provide satisfiable vibration-isolation effect, but can also cause too much displacement of building structure. Install damping material beneath the building can absorb part of the energy of earthquake, and decrease the damage, and can solve the problem of displacement of building, therefore, damping material can be considered as an ideal vibration-isolation material. Install energy-attenuation equipment can also reduce vibration but the design of the equipment is extremely difficult.
黑暗的力量
We study the magic power of dark energy and dark matter by using theoretical derivation and numerical simulations. We found that: 1. The dark energy will gain kinetic energy from the moving dark matter through gravitational interaction. Due to the law of energy conservation, the motion of the dark matter will slow down and satisfy Ek(t)−Ek0 ∝ρDE1.92 t, where Ek(t) is the kinetic energy of the dark matter, Ek0 is its initial kinetic energy, ρDE is the energy density of the dark energy, and t is the time. 2. The formation history and the structure of galaxies will be different due to the existence of dark energy. The more the dark energy, the earlier the formation of the galaxy core. In addition, the kinetic energy Ek(R) as a function of R will be different if the ρDE is different. Thus we can observationally measure the Ek(R) of galaxies, compare it will our results here, and then deduce the ρDE in our universe. The results here can be applied to the observations in the near future.
我們藉由理論的推導,配合電腦模擬的手段,來探討宇宙中黑暗物質和黑暗能量的神祕力量。我們發現:一、黑暗能量會透過重力交互作用而從運動中的黑暗物質獲得力學能,而且因力學能守恆,致使黑暗物質的速率減慢,滿足 Ek(t)−Ek0 ∝ρDE1.92 t, 其中 Ek(t) 為黑暗物質的動能, Ek0 為其初始動能, ρDE 為黑暗能量的密度,t 為時間。二、星系的形成過程及結構,會因黑暗能量的存在而改變。黑暗能量越多時,星系的核心會越早形成。而且動能 Ek(R) 隨著至星系中心距離 R 的變化,會因 ρDE 的不同而不同,因此可以試圖量測宇宙中星系的 Ek(R) ,然後和這裡的結果比對,即可推導出宇宙中的 ρDE 。這些研究成果,將可直接應用在未來的觀測結果上。