What is a photon?

We discuss the absorber theory of radiation as put forward by Wheeler and Feynman. We show that it gives a better understanding of the photon compared to the usual quantum electrodynamics (QED) picture.     

What is a dysfunctional school?

Abstract

Whether or not a school is dysfunctional depends largely on how dysfunctionality in schools is defined and measured. Dysfunctionality, as any construct, is subject to definition and interpretation, and it is thus always marked by perspectivism. But regardless of the definition games occasionally played by academics, some form of reality takes place beyond the constructivist horizon. Moreover, perspectivism and definition games may justify and even create adverse consequences within a school's lived reality. A definition focussing on Grade 12 pass rates, for example, tends to implicate teachers, while a definition focussing on infrastructure tends to exculpate teachers and incriminate government and administration. Accordingly, this article will not end but begin with the adage that a dysfunctional school is what one defines a dysfunctional school to be, and it will explore the conditions and consequences of conceptual variations.     

What is a p‐value?

An in‐class activity is described that can be used not only to motivate hypothesis testing, but also to understand and compute the p‐value and power in a statistical test.     

What is this?

"嘿……你认得我吗?""哎哟!谁,谁打我的头……"你!说的就是你,不要这么突然跑出来吓人啊!哼,就算你是我们今天请来的客人,也要乖乖守规矩才可以!咳咳,大家好,让我把台词说完……来,猜猜看今天来到我们这个栏目的朋友是谁吧!当然,按老规矩,要先给它画张像才可以!     

What is this?

"在每一个天空被洒满朦胧月色的夜晚,我从幽深的森林里启程,来到人们居住的地方,吸食人们的梦。我不会害怕在吃梦的时候吵醒熟睡着的人们。因为我生性胆怯,在夜色中,只会发出轻轻的、摇篮曲一样的叫声……"传说中我过着这样的生活。然而你真的知道我是什么吗?     

What is this?

也许你觉得我很可怕,但我其实是个傻娃娃!咦?你在笑什么,难道觉得我在说大话?哼,不要小看了我啊。如果你了解我,一定就不会这样嘲笑我了。我的名字?现在可不能告诉你,老规矩,来猜猜看吧!     

What is transit?

The event of Venus passing in front of the Sun is called the transit. This is equivalent to an eclipse with the Moon replaced by the planet Venus. In this article, the rarity and importance of the event and the historical explorations are discussed.     

What is a virtual world? Definition and classification

In 2008, articles by Bell and Schroeder provided an initial platform from which to develop a coherent definition of the term ‘virtual worlds’. Yet over the past ten years, there has been little development of the term. Instead there is confusion in the literature, with the introduction of new terms which are at times used to classify the type of virtual world and at others are used synonymously with the term. At the same time there has been a resurgence of interest in the potential of virtual reality which further muddies the conceptual waters. While the lack of a clear and common understanding of a term is not uncommon, there are implications for researchers and practitioners. To address these issues, this paper presents a new framework for the definition of virtual worlds, arguing what it is for a world to be virtual, the user experience that is a necessary part of this and the technical features which afford this. For the first time the relationships between commonly confused terms and technologies are identified to provide a much needed conceptual clarity for researchers and educators.