Massless particles and field perturbations such as gravitational waves also travel at the speed c in vacuum. He explored the consequences of that postulate by deriving the theory of relativity and in doing so showed that the parameter c had relevance outside of the context of light and electromagnetism. In 1905, Albert Einstein postulated that the speed of light c with respect to any inertial frame is a constant and is independent of the motion of the light source. In 1865, James Clerk Maxwell proposed that light was an electromagnetic wave, and therefore travelled at the speed c appearing in his theory of electromagnetism. Progressively more accurate measurements of its speed came over the following centuries. Ole Rømer first demonstrated in 1676 that light travels at a finite speed (non-instantaneously) by studying the apparent motion of Jupiter's moon Io. The speed of light can be used with time of flight measurements to measure large distances to high precision. The finite speed of light also ultimately limits the data transfer between the CPU and memory chips in computers. The light seen from stars left them many years ago, allowing the study of the history of the universe by looking at distant objects. In communicating with distant space probes, it can take minutes to hours for a message to get from Earth to the spacecraft, or vice versa.
For many practical purposes, light and other electromagnetic waves will appear to propagate instantaneously, but for long distances and very sensitive measurements, their finite speed has noticeable effects. According to the special theory of relativity, c is the upper limit for the speed at which conventional matter, energy or any signal carrying information can travel through space.Īll forms of electromagnetic radiation - not just visible light - travel at the speed of light. Its exact value is defined as 299 792 458 metres per second (approximately 300 000 km/s or 186 000 mi/s). Conclusions Causal understanding leads to more coherent understanding of clinical conditions, which in turn leads to expert‐like behaviour.The speed of light in vacuum, commonly denoted c, is a universal physical constant that is important in many areas of physics.
In study 2 there was an interaction causal students performed better under speeded conditions (71% versus 66%) but worse under thoroughness conditions (67% versus 73%), as predicted. Results In study 1, while there was no difference in recognising old words (90% versus 91%), the causal group was better able to recognise encapsulated and novel consistent words (50% versus 41%) (P = 0.02). In study 2, they were asked to diagnose new cases either (i) as quickly as possible or (ii) taking their time. In study 1, they were then given a recognition memory task. One group learned signs and symptoms alone the second group also learned a causal explanation.
Methods Two studies were conducted involving 4 ‘pseudo‐endocrinology’ diseases and undergraduate psychology students. Hypotheses In comparison to students who simply learn the features of 4 diagnostic categories, students who learn a causal explanation will: (a) recognise words describing encapsulated knowledge more accurately and (b) maintain or improve diagnostic performance under speeded conditions. In the present paper we show that students who learn causal explanations have a more coherent understanding of the relation between diseases and clinical features which, in turn, influences recognition of words or phrases describing ‘encapsulated knowledge’ and the ability to maintain performance under speeded conditions. Schmidt has postulated that expert clinicians maintain this knowledge in ‘encapsulated’ form, indexed by words or phrases describing the processes. Woods, Nicole N Howey, Elizabeth H A Brooks, Lee R Norman, Geoffrey Rīackground The role of basic science, which provides causal explanations for clinical phenomena in medical education, is poorly understood. Speed kills? Speed, accuracy, encapsulations and causal understanding Speed kills? Speed, accuracy, encapsulations and causal understanding
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