Episode 100: Unsolved Problems in Science

• January 19th, 2020

In this special celebratory 100th episode, I discuss six major unsolved problems in science: the P vs NP problem in computer science, the mystery of dark matter in physics, the existence of the island of stability in chemistry, the historical occurrence of a snowball Earth scenario from geology, the protein folding problem from biochemistry, and the origin of the Cambrian explosion in evolutionary biology. I also discuss some important ideas relating to the future of the podcast.


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Episode 99: Plant Reproduction and Fruit

• January 6th, 2020

A discussion of the method of reproduction of flowering plants, including an overview of the structure and function of the different components of the flower, pollination, double fertilisation, and seed formation, dispersal, and germination. I also discuss the different types of fruit and vegetables and how the different components of the plant relate to the parts that we consume. I conclude with a brief overview of non-edible plant products, including fibres, resin, and sap. Recommended prerequisite is Episode 97: Plant Structure and Function.

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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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