三角形與其外接錐線的生成錐線性質探討
本研究源自三角形的重心及其外接圓所構作的線段比值的古老幾何性質，我們不但推廣原命題，還創造新命題：給定△ABC與其外接錐線Γ，令直線AG, BG, CG分別交Γ 於 A', B', C' 點，再取任意k值，探討P點集合的性質。 Γ3, k={P|AA'/PA' + BB'/PB' +CC'/PC'=k} (1)Γ3,k為二次曲線系，其橢圓、拋物線、雙曲線之形態不因k值而改變，而是被外接錐線Γ所決定。 (2)發現△ABC重心 G、Γ中心O、Γ3,k 中心O3,k 的共線性及比例常數。 (3)完整劃分 Γ3,k的非退化與退化型態，並發現只有Γ3,k 為橢圓時，k 值有跳躍現象。 (4) 發現錐線Γ上取相異六點而生成兩個錐線Γ3,k、Π3,k重合的充分條件。 最後，我們以「錐線 Γ 上取一點、兩點到多點」的線性組合手法，推廣多邊形與其外接錐線的生成錐線Γn,k之性質。
The Locus of Mid-Tangent Points of Planar Curves
In this project, we defined a mid-tangent point with respect to a fixed point X and a tangent at a point Y on a planar curve C as a point on the tangent that is equidistant from X and Y. We studied the locus of mid-tangent points of conic sections. We found that the locus of mid-tangent points of most conic sections are non-linear curves. However, we observed and proved by using Euclidean geometry that the locus of mid-tangent points of circles are straight lines. The mapping defined by mid-tangent points was studied further. The similarity between a mid-tangent mapping and a stereographic projection was displayed as a one – to – one correspondence function. We also extended the concept of mid-tangent points to three dimensional space and found that the similarity with the stereographic projection was retained in higher dimensions. Finally, we studied the locus of mid-tangent points of a sphere to create a mapping of the sphere to a plane.
Investigating the Effect of Coloured Light on the Behaviour and Learning of Lymnae stagnalis
Lymnae stagnalis (pond snail) is emerging as a preferable invertebrate model in understanding neurological mechanisms because of its simple nervous system. A three-cell network mediates behaviours such as aerial respiration and research has shown that small, subtle changes occurring across the network might result in a disruption of natural behaviour (Lukowiak et al. 1995). It is also known that Lymnae features a more developed eye than other molluscs and studies have shown that various wavelengths of light can activate photoreceptors producing distinct electrophysiological responses (Sakakibara et al. 2004). However, no studies have looked beyond the electrophysiological response. The purpose of this project was to determine if coloured light would firstly, elicit a behavioural response as observed in its movement and secondly, affect learning and memory through the operant conditioning of its aerial respiration.
How to spill your coffee
We all do it – walk along with a cup in hand, and carelessly spill it. While it’s usually more annoying than anything else, it happens to affect almost all of us, and little is done to minimise the likelihood of it occurring. So my aim was to explain the physics behind why we spill drinks when we walk, and to investigate how we can minimise the likelihood of this occurring. I broke this investigation into two distinct parts, explaining the system of the cup, and explaining the effect of walking. From initial observations, it was clear that the cup was a resonating system. Like any resonating system, the cup has a natural frequency. When the cup is oscillated – moved back and forth – at near this frequency, the size of the liquid oscillations is very large. This is because the acceleration is in phase with the motion of the liquid, so in each cycle maximum energy is input into the system. In my investigation I experimentally measured this natural frequency, and created a mathematical model to explain this frequency. It was also found that as the size of liquid oscillations in the cup increases, so does distortion of the fluid surface, possibly enabling spilling. To systematically analyse the effect of walking, I had subjects walk on a treadmill, so walking surface and speed were controlled. However, I also needed an accurate way of measuring the motion of a carried cup. Firstly, I tried to use video analysis; however I found this far too imprecise for measuring small changes in velocity of a cup. In the end I used a smartphone to record the acceleration of a carried cup, as acceleration is what causes the movement of liquid in a cup. This allowed surprisingly accurate measurements to be made, and allowed both the size and frequency of the acceleration to be recorded. In order to relate the system of the cup and the oscillation provided whilst walking I conducted a qualitative experiment into the effect of stride frequency on the likelihood of spilling. When stride frequency was very close to the natural frequency of the cup, spilling occurred almost instantly, while it did not occur if stride frequency was much higher or lower. In the end, my research showed that to minimise the likelihood of spilling your drink walk slowly, use a narrow cup, focus on walking smoothly, and fill the cup well below the rim. Despite this, some people happen to be much smoother cup carriers than others, likely due to their individual biomechanics. And, if you really don’t want to spill your drink, you can always use a lid.