Episode 98: Electromagnetic Radiation

• December 28th, 2018

An overview of the nature and properties of electromagnetic radiation, including a discussion of the electromagnetic spectrum, the nature of photons, the speed of light, near and far field radiation, and technological applications of electromagnetic radiation in AM and FM radiation and microwave ovens. Recommended pre-listening is Episode 61: Magnetism and Episode 57: Electric Current and Circuits.

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Episode 97: Plant Structure and Function

• June 27th, 2018

An overview of the basic morphology and physiology of plants, including a discussion of the main types of plants, stems, roots, leaves, plant transport, meristems, plant nutrition, and plant sensory systems.

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Special Episode - Jared Bauer on Science and Philosophy in Movies

• April 2nd, 2018

In this special episode I am joined by Jared Bauer, cofounder of Wisecrack, to discuss science and philosophy in movies and popular culture. We cover a range of topics including how science is portrayed in movies, how the film medium leads to science and history being presented in particular ways, and how movies and popular culture can be used as a vehicle for promoting scientific and philosophical inquiry.

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Episode 96: How Computers Work Part VI - High Level Programming and Software

• March 2nd, 2018

In the final episode of our series on computers, I give an introduction to high-level programming languages, how they relate to assembly language and machine code, and how the compiler converts high level programs into a form that can be executed by the processor. I then outline some of the key components to high-level programming, such as data structures, control structures, and algorithms, before sketching an example implementation of a simple game. I conclude with an integrative summary of computer structure from silicon up to the operating system.

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Episode 95: How Computers Work Part V - Assembly Language and the Operating System

• February 14th, 2018

In this the fifth episode of the series 'how computers work', I begin with a summary of some of the major methods of improving the performance of the central processing unit, including pipelining, cache memory, branch prediction, and parallel processing. Following a brief introduction to assembly langague and its relationship to the machine code, I then discuss the operating system and how it interfaces with the hardware to manage program memory, system calls, input/output, and processes.

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Episode 94: How Computers Work Part IV - Processor Architecture and Machine Code

• February 4th, 2018

In this fourth part in our series on computers, I begin with an overview of the von Neumann architecture used in most modern computers. This leads in a discussion of the structure and operation of the central processing unit, covering the instruction register, the program counter, main memory, the data and address buses, the ALU, and the control Unit. I then discuss the purpose and implementation of a number of key operations in the instruction set architecture, including arithmetic operations, data movement operations, and conditional branches.

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Episode 93: How Computers Work Part III - Logic Gates and Components

• January 20th, 2018

In this third part of the series on computers I begin with an overview of Boolean algebra, including a discussion of key logic functions such as NOT, AND, and OR, and also discuss how CMOS logic gates implementing these functions are fabricated from transistors. I then survey the wide variety of logic components used in electronic circuits, including the multiplexor, adder, tristate buffer, flip-flops, comparator, and clock generator, and discuss the functions fulfilled by these devices in modern computers.

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Episode 92: How Computers Work Part II - Silicon and Transistors

• January 10th, 2018

In this second episode in the series, I explain binary digital coding to motivate a discussion of the operation of transistors. Beginning with an examination of the properties of semiconductors and why they are useful for constructing transistors, I then examine how MOSFET transistors are constructed by combining pMOS and nMOS semiconductors.

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Episode 91: How Computers Work Part I - What is a Computer?

• December 30th, 2017

We begin our series discussing how computers work with an overview of the theory of computation, including a discussion of Turing machines and Turing completeness, and a brief history of early analog and digital computers. I also provide an introduction to the key components of a modern computer, and review the different levels in the hierarchy of computer organisation.

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Episode 90: Climate Systems

• December 1st, 2017

An analysis of the major factors influencing climactic variation over Earth's surface, including a discussion of the effect of differential heating at different latitudes, the impact of continentality and sea breezes, the causes of monsoons, the coriolis effect, atmospheric circulation cells, the jet streams, and thermohaline circulation currents in Earth's oceans. Recommended pre-listening is Episode 88: Cartography and Earths Seasons, and Episode 89: The Atmosphere.

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