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.

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.

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.

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.

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.

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.

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.

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.

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.