Author: Bob Bonnet
Publisher: McGraw Hill Professional
ISBN: 0071600280
Category : Technology & Engineering
Languages : en
Pages : 210
Book Description
SHAKE UP YOUR SCIENCE FAIR WITH THESE CUTTING-EDGE, ATTENTION-GRABBING PROJECTS! Want to win first place in the next science fair? 46 Science Fair Projects for the Evil Genius has everything you need to create amazing, sophisticated projects that will wow the judges and keep everyone talking long after the awards are handed out. Using inexpensive, easy-to-find parts and tools, and following standard science fair requirements, these creative new projects test 46 theories from various disciplines, including physics, astronomy, energy, environmental science, and economics. Each project begins with an intriguing hypothesis that leaves plenty of room for you to add your own tweaks, making the project entirely different and new-the only limit is your imagination! 46 Science Fair Projects for the Evil Genius: Features instructions and plans for 46 inventive, winning projects, complete with 100 how-to illustrations Shows you how to assemble, design, and build devices to test the hypotheses offered for each project Leaves room for you to customize your project and create several variations, so the experiment is entirely your own! Removes the frustration-factor-all the parts you need are listed, along with sources Regardless of your skill level, 46 Science Fair Projects for the Evil Genius provides you with all the parts lists and tools you need to test the hypotheses and complete projects with ease, such as: Water, Water, Everywhere-the effect of salt water flooding a lawn “Vlip!”-dogs respond to sounds, not the meaning of words Web Crawler-the effectiveness of Internet search engines M&M Ring around the World-the validity of sample size “Commercial” TV-comparison of programming to advertising content Sounds fishy-do goldfish have a water temperature preference? Split and Dip-strategy for making money in the stock market High-Tech Times-the willingness of people of different ages to adapt to new technology Not Just Lemonade-is adding lemon to cleaners just for marketing? Kinetic Pendulum-the relationship between a pendulum, an arc, and time
46 Science Fair Projects for the Evil Genius
125 Physics Projects for the Evil Genius
Author: Jerry Silver
Publisher: McGraw Hill Professional
ISBN: 0071626077
Category : Technology & Engineering
Languages : en
Pages : 354
Book Description
125 Wickedly Fun Ways to Test the Laws of Physics! Now you can prove your knowledge of physics without expending a lot of energy. 125 Physics Projects for the Evil Genius is filled with hands-on explorations into key areas of this fascinating field. Best of all, these experiments can be performed without a formal lab, a large budget, or years of technical experience! Using easy-to-find parts and tools, this do-it-yourself guide offers a wide variety of physics experiments you can accomplish on your own. Topics covered include motion, gravity, energy, sound, light, heat, electricity, and more. Each of the projects in this unique guide includes parameters, a detailed methodology, expected results, and an explanation of why the experiment works. 125 Physics Projects for the Evil Genius: Features step-by-step instructions for 125 challenging and fun physics experiments, complete with helpful illustrations Allows you to customize each experiment for your purposes Includes details on the underlying principles behind each experiment Removes the frustration factor--all required parts are listed, along with sources 125 Physics Projects for the Evil Genius provides you with all of the information you need to demonstrate: Constant velocity Circular motion and centripetal force Gravitational acceleration Newton's laws of motion Energy and momentum The wave properties of sound Refraction, reflection, and the speed of light Thermal expansion and absolute zero Electrostatic force, resistance, and magnetic levitation The earth's magnetic field The size of a photon, the charge of an electron, and the photoelectric effect And more
Publisher: McGraw Hill Professional
ISBN: 0071626077
Category : Technology & Engineering
Languages : en
Pages : 354
Book Description
125 Wickedly Fun Ways to Test the Laws of Physics! Now you can prove your knowledge of physics without expending a lot of energy. 125 Physics Projects for the Evil Genius is filled with hands-on explorations into key areas of this fascinating field. Best of all, these experiments can be performed without a formal lab, a large budget, or years of technical experience! Using easy-to-find parts and tools, this do-it-yourself guide offers a wide variety of physics experiments you can accomplish on your own. Topics covered include motion, gravity, energy, sound, light, heat, electricity, and more. Each of the projects in this unique guide includes parameters, a detailed methodology, expected results, and an explanation of why the experiment works. 125 Physics Projects for the Evil Genius: Features step-by-step instructions for 125 challenging and fun physics experiments, complete with helpful illustrations Allows you to customize each experiment for your purposes Includes details on the underlying principles behind each experiment Removes the frustration factor--all required parts are listed, along with sources 125 Physics Projects for the Evil Genius provides you with all of the information you need to demonstrate: Constant velocity Circular motion and centripetal force Gravitational acceleration Newton's laws of motion Energy and momentum The wave properties of sound Refraction, reflection, and the speed of light Thermal expansion and absolute zero Electrostatic force, resistance, and magnetic levitation The earth's magnetic field The size of a photon, the charge of an electron, and the photoelectric effect And more
Holography Projects for the Evil Genius
Author: Gavin D J Harper
Publisher: McGraw Hill Professional
ISBN: 0071624015
Category : Technology & Engineering
Languages : en
Pages : 177
Book Description
Take Your Imagination to Another Dimension This wickedly inventive guide explores the art and science of holography and shows you how to create your own intriguing holograms using inexpensive materials. Holography Projects for the Evil Genius explains the tools and techniques you need to know to represent three dimensions on a flat, two-dimensional plane. Using easy-to-find components and equipment, this do-it-yourself book presents a wide variety of holography projects--including science fair ideas--that are guaranteed to impress. You'll find detailed guidelines and parameters as well as discussions of the theory behind the practice. Holography Projects for the Evil Genius: Features step-by-step instructions and helpful illustrations for each project Allows you to customize your projects Includes details on the scientific principles behind the projects Removes the frustration factor--all required parts are listed, along with sources Enlightening coverage of: The history of holography Human vision basics Practical optics How to bend and distort laser light to form a hologram Holographic chemistry Setting up your holography workshop Working with lasers, glass plates, and film Basic to advanced holographic setups Advanced holographic chemical preparations Computer-generated holography Electronic circuits for holographers
Publisher: McGraw Hill Professional
ISBN: 0071624015
Category : Technology & Engineering
Languages : en
Pages : 177
Book Description
Take Your Imagination to Another Dimension This wickedly inventive guide explores the art and science of holography and shows you how to create your own intriguing holograms using inexpensive materials. Holography Projects for the Evil Genius explains the tools and techniques you need to know to represent three dimensions on a flat, two-dimensional plane. Using easy-to-find components and equipment, this do-it-yourself book presents a wide variety of holography projects--including science fair ideas--that are guaranteed to impress. You'll find detailed guidelines and parameters as well as discussions of the theory behind the practice. Holography Projects for the Evil Genius: Features step-by-step instructions and helpful illustrations for each project Allows you to customize your projects Includes details on the scientific principles behind the projects Removes the frustration factor--all required parts are listed, along with sources Enlightening coverage of: The history of holography Human vision basics Practical optics How to bend and distort laser light to form a hologram Holographic chemistry Setting up your holography workshop Working with lasers, glass plates, and film Basic to advanced holographic setups Advanced holographic chemical preparations Computer-generated holography Electronic circuits for holographers
Programming Video Games for the Evil Genius
Author: Ian Cinnamon
Publisher: McGraw Hill Professional
ISBN: 0071643532
Category : Technology & Engineering
Languages : en
Pages : 336
Book Description
IF EVIL'S YOUR NAME, THEN THESE ARE YOUR GAMES! Always wanted to be a genius game creator? This Evil Genius guide goes far beyond a typical programming class or text to reveal insider tips for breaking the rules and constructing wickedly fun games that you can tweak and customize to suit your needs! In Programming Video Games for the Evil Genius, programming wunderkind Ian Cinnamon gives you everything you need to create and control 57 gaming projects. You'll find easy-to-follow plans featuring Java, the most universal programming language, that run on any PC, Mac, or Linux computer. Illustrated instructions and plans for an awesome mix of racing, board, shoot 'em up, strategy, retro, and puzzle games Gaming projects that vary in difficulty-starting with simple programs and progressing to sophisticated projects for programmers with advanced skills An interactive companion website featuring a free Java compiler, where you can share your projects with Evil Geniuses around the globe Removes the frustration-factor-all the parts you need are listed, along with sources Regardless of your skill level, Programming Video Games for the Evil Genius provides you with all the strategies, code, and insider programming advice you need to build and test your games with ease, such as: Radical Racing Screen Skier Whack an Evil Genius Tic-Tac-Toe Boxing Snake Pit Space Destroyers Bomb Diffuser Trapper Oiram Java Man Memory Ian Says
Publisher: McGraw Hill Professional
ISBN: 0071643532
Category : Technology & Engineering
Languages : en
Pages : 336
Book Description
IF EVIL'S YOUR NAME, THEN THESE ARE YOUR GAMES! Always wanted to be a genius game creator? This Evil Genius guide goes far beyond a typical programming class or text to reveal insider tips for breaking the rules and constructing wickedly fun games that you can tweak and customize to suit your needs! In Programming Video Games for the Evil Genius, programming wunderkind Ian Cinnamon gives you everything you need to create and control 57 gaming projects. You'll find easy-to-follow plans featuring Java, the most universal programming language, that run on any PC, Mac, or Linux computer. Illustrated instructions and plans for an awesome mix of racing, board, shoot 'em up, strategy, retro, and puzzle games Gaming projects that vary in difficulty-starting with simple programs and progressing to sophisticated projects for programmers with advanced skills An interactive companion website featuring a free Java compiler, where you can share your projects with Evil Geniuses around the globe Removes the frustration-factor-all the parts you need are listed, along with sources Regardless of your skill level, Programming Video Games for the Evil Genius provides you with all the strategies, code, and insider programming advice you need to build and test your games with ease, such as: Radical Racing Screen Skier Whack an Evil Genius Tic-Tac-Toe Boxing Snake Pit Space Destroyers Bomb Diffuser Trapper Oiram Java Man Memory Ian Says
Arduino + Android Projects for the Evil Genius: Control Arduino with Your Smartphone or Tablet
Author: Simon Monk
Publisher: McGraw Hill Professional
ISBN: 0071775978
Category : Technology & Engineering
Languages : en
Pages : 223
Book Description
TEAM ARDUINO UP WITH ANDROID FOR SOME MISCHIEVOUS FUN! Filled with practical, do-it-yourself gadgets, Arduino + Android Projects for the Evil Genius shows you how to create Arduino devices and control them with Android smartphones and tablets. Easy-to-find equipment and components are used for all the projects in the book. This wickedly inventive guide covers the Android Open Application Development Kit (ADK) and USB interface and explains how to use them with the basic Arduino platform. Methods of communication between Android and Arduino that don't require the ADK--including sound, Bluetooth, and WiFi/Ethernet are also discussed. An Arduino ADK programming tutorial helps you get started right away. Arduino + Android Projects for the Evil Genius: Contains step-by-step instructions and helpful illustrations Provides tips for customizing the projects Covers the underlying principles behind the projects Removes the frustration factor--all required parts are listed Provides all source code on the book's website Build these and other devious devices: Bluetooth robot Android Geiger counter Android-controlled light show TV remote Temperature logger Ultrasonic range finder Home automation controller Remote power and lighting control Smart thermostat RFID door lock Signaling flags Delay timer
Publisher: McGraw Hill Professional
ISBN: 0071775978
Category : Technology & Engineering
Languages : en
Pages : 223
Book Description
TEAM ARDUINO UP WITH ANDROID FOR SOME MISCHIEVOUS FUN! Filled with practical, do-it-yourself gadgets, Arduino + Android Projects for the Evil Genius shows you how to create Arduino devices and control them with Android smartphones and tablets. Easy-to-find equipment and components are used for all the projects in the book. This wickedly inventive guide covers the Android Open Application Development Kit (ADK) and USB interface and explains how to use them with the basic Arduino platform. Methods of communication between Android and Arduino that don't require the ADK--including sound, Bluetooth, and WiFi/Ethernet are also discussed. An Arduino ADK programming tutorial helps you get started right away. Arduino + Android Projects for the Evil Genius: Contains step-by-step instructions and helpful illustrations Provides tips for customizing the projects Covers the underlying principles behind the projects Removes the frustration factor--all required parts are listed Provides all source code on the book's website Build these and other devious devices: Bluetooth robot Android Geiger counter Android-controlled light show TV remote Temperature logger Ultrasonic range finder Home automation controller Remote power and lighting control Smart thermostat RFID door lock Signaling flags Delay timer
tinyAVR Microcontroller Projects for the Evil Genius
Author: Dhananjay Gadre
Publisher: McGraw Hill Professional
ISBN: 007174455X
Category : Technology & Engineering
Languages : en
Pages : 272
Book Description
CREATE FIENDISHLY FUN tinyAVR MICROCONTROLLER PROJECTS This wickedly inventive guide shows you how to conceptualize, build, and program 34 tinyAVR microcontroller devices that you can use for either entertainment or practical purposes. After covering the development process, tools, and power supply sources, tinyAVR Microcontroller Projects for the Evil Genius gets you working on exciting LED, graphics LCD, sensor, audio, and alternate energy projects. Using easy-to-find components and equipment, this hands-on guide helps you build a solid foundation in electronics and embedded programming while accomplishing useful--and slightly twisted--projects. Most of the projects have fascinating visual appeal in the form of large LED-based displays, and others feature a voice playback mechanism. Full source code and circuit files for each project are available for download. tinyAVR Microcontroller Projects for the Evil Genius: Features step-by-step instructions and helpful illustrations Allows you to customize each project for your own requirements Offers full source code for all projects for download Build these and other devious devices: Flickering LED candle Random color and music generator Mood lamp VU meter with 20 LEDs Celsius and Fahrenheit thermometer RGB dice Tengu on graphics display Spinning LED top with message display Contactless tachometer Electronic birthday blowout candles Fridge alarm Musical toy Batteryless infrared remote Batteryless persistence-of-vision toy Each fun, inexpensive Evil Genius project includes a detailed list of materials, sources for parts, schematics, and lots of clear, well-illustrated instructions for easy assembly. The larger workbook-style layout and convenient two-column format make following the step-by-step instructions a breeze. Make Great Stuff! TAB, an imprint of McGraw-Hill Professional, is a leading publisher of DIY technology books for makers, hackers, and electronics hobbyists.
Publisher: McGraw Hill Professional
ISBN: 007174455X
Category : Technology & Engineering
Languages : en
Pages : 272
Book Description
CREATE FIENDISHLY FUN tinyAVR MICROCONTROLLER PROJECTS This wickedly inventive guide shows you how to conceptualize, build, and program 34 tinyAVR microcontroller devices that you can use for either entertainment or practical purposes. After covering the development process, tools, and power supply sources, tinyAVR Microcontroller Projects for the Evil Genius gets you working on exciting LED, graphics LCD, sensor, audio, and alternate energy projects. Using easy-to-find components and equipment, this hands-on guide helps you build a solid foundation in electronics and embedded programming while accomplishing useful--and slightly twisted--projects. Most of the projects have fascinating visual appeal in the form of large LED-based displays, and others feature a voice playback mechanism. Full source code and circuit files for each project are available for download. tinyAVR Microcontroller Projects for the Evil Genius: Features step-by-step instructions and helpful illustrations Allows you to customize each project for your own requirements Offers full source code for all projects for download Build these and other devious devices: Flickering LED candle Random color and music generator Mood lamp VU meter with 20 LEDs Celsius and Fahrenheit thermometer RGB dice Tengu on graphics display Spinning LED top with message display Contactless tachometer Electronic birthday blowout candles Fridge alarm Musical toy Batteryless infrared remote Batteryless persistence-of-vision toy Each fun, inexpensive Evil Genius project includes a detailed list of materials, sources for parts, schematics, and lots of clear, well-illustrated instructions for easy assembly. The larger workbook-style layout and convenient two-column format make following the step-by-step instructions a breeze. Make Great Stuff! TAB, an imprint of McGraw-Hill Professional, is a leading publisher of DIY technology books for makers, hackers, and electronics hobbyists.
Creating Science Fair Projects with Cool New Digital Tools
Author: Susan Henneberg
Publisher: The Rosen Publishing Group, Inc
ISBN: 1477718362
Category : Juvenile Nonfiction
Languages : en
Pages : 50
Book Description
A science fair project is an opportunity for teens to choose a subject of interest, investigate it using the scientific method, and share their findings. While the scientific method never goes out of date, much about science fair research and presentation has changed with the advent of digital tools. Readers learn how they can use digital tools to brainstorm a question, research and take notes, collaborate with teammates, record and organize data, and create presentations using multimedia. As required by the Common Core, readers learn to use technology to produce and publish their work and to collaborate with others.
Publisher: The Rosen Publishing Group, Inc
ISBN: 1477718362
Category : Juvenile Nonfiction
Languages : en
Pages : 50
Book Description
A science fair project is an opportunity for teens to choose a subject of interest, investigate it using the scientific method, and share their findings. While the scientific method never goes out of date, much about science fair research and presentation has changed with the advent of digital tools. Readers learn how they can use digital tools to brainstorm a question, research and take notes, collaborate with teammates, record and organize data, and create presentations using multimedia. As required by the Common Core, readers learn to use technology to produce and publish their work and to collaborate with others.
Mechatronics for the Evil Genius
Author: Newton C. Braga
Publisher: McGraw Hill Professional
ISBN: 0071710795
Category : Technology & Engineering
Languages : en
Pages : 513
Book Description
The popular evil genius format provides hobbyists with a fun and inexpensive way to learn Mechatronics (the merger of electronics and mechanics) via 25 complete projects. Projects include: mechanical race car, combat robot, ionic motor, electromagnet, robotic arm, light beam remote control, and more Includes "parts lists" and "tool bin" for each project Covers all the preparation needed to begin building, such as "how to solder," "how to recognize components and diagrams, "how to read a schematic," etc.
Publisher: McGraw Hill Professional
ISBN: 0071710795
Category : Technology & Engineering
Languages : en
Pages : 513
Book Description
The popular evil genius format provides hobbyists with a fun and inexpensive way to learn Mechatronics (the merger of electronics and mechanics) via 25 complete projects. Projects include: mechanical race car, combat robot, ionic motor, electromagnet, robotic arm, light beam remote control, and more Includes "parts lists" and "tool bin" for each project Covers all the preparation needed to begin building, such as "how to solder," "how to recognize components and diagrams, "how to read a schematic," etc.
PICAXE Microcontroller Projects for the Evil Genius
Author: Ron Hackett
Publisher: McGraw Hill Professional
ISBN: 0071703276
Category : Technology & Engineering
Languages : en
Pages : 288
Book Description
WHIP UP SOME FIENDISHLY FUN PICAXE MICROCONTROLLER DEVICES "Ron has worked hard to explain how the PICAXE system operates through simple examples, and I'm sure his easy-to-read style will help many people progress with their PICAXE projects." --From the Foreword by Clive Seager, Revolution Education Ltd. This wickedly inventive guide shows you how to program, build, and debug a variety of PICAXE microcontroller projects. PICAXE Microcontroller Projects for the Evil Genius gets you started with programming and I/O interfacing right away, and then shows you how to develop a master processor circuit. From "Hello, World!" to "Hail, Octavius!" All the projects in Part I can be accomplished using either an M or M2 class PICAXE processor, and Part II adds 20X2-based master processor projects to the mix. Part III culminates in the creation of Octavius--a sophisticated robotics experimentation platform featuring a 40X2 master processor and eight breadboard stations which allow you to develop intelligent peripherals to augment Octavius' functioning. The only limit is your imagination! PICAXE Microcontroller Projects for the Evil Genius: Features step-by-step instructions and helpful photos and illustrations Allows you to customize each project for your purposes Offers all the programs in the book free for download Removes the frustration factor--all required parts are listed, along with sources Build these and other devious devices: Simple mini-stereo jack adapter USBS-PA3 PICAXE programming adapter Power supply Three-state digital logic probe 20X2 master processor circuit TV-R input module 8-bit parallel 16X2 LCD board Serialized 16X2 LCD Serialized 4X4 matrix keypad SPI 4-digit LED display Countdown timer Programmable, multi-function peripheral device and operating system Octavius--advanced robotics experimentation platform L298 dual DC motor controller board Each fun, inexpensive Evil Genius project includes a detailed list of materials, sources for parts, schematics, and lots of clear, well-illustrated instructions for easy assembly. The larger workbook-style layout and convenient two-column format make following the step-by-step instructions a breeze. Make Great Stuff! TAB, an imprint of McGraw-Hill Professional, is a leading publisher of DIY technology books for makers, hackers, and electronics hobbyists.
Publisher: McGraw Hill Professional
ISBN: 0071703276
Category : Technology & Engineering
Languages : en
Pages : 288
Book Description
WHIP UP SOME FIENDISHLY FUN PICAXE MICROCONTROLLER DEVICES "Ron has worked hard to explain how the PICAXE system operates through simple examples, and I'm sure his easy-to-read style will help many people progress with their PICAXE projects." --From the Foreword by Clive Seager, Revolution Education Ltd. This wickedly inventive guide shows you how to program, build, and debug a variety of PICAXE microcontroller projects. PICAXE Microcontroller Projects for the Evil Genius gets you started with programming and I/O interfacing right away, and then shows you how to develop a master processor circuit. From "Hello, World!" to "Hail, Octavius!" All the projects in Part I can be accomplished using either an M or M2 class PICAXE processor, and Part II adds 20X2-based master processor projects to the mix. Part III culminates in the creation of Octavius--a sophisticated robotics experimentation platform featuring a 40X2 master processor and eight breadboard stations which allow you to develop intelligent peripherals to augment Octavius' functioning. The only limit is your imagination! PICAXE Microcontroller Projects for the Evil Genius: Features step-by-step instructions and helpful photos and illustrations Allows you to customize each project for your purposes Offers all the programs in the book free for download Removes the frustration factor--all required parts are listed, along with sources Build these and other devious devices: Simple mini-stereo jack adapter USBS-PA3 PICAXE programming adapter Power supply Three-state digital logic probe 20X2 master processor circuit TV-R input module 8-bit parallel 16X2 LCD board Serialized 16X2 LCD Serialized 4X4 matrix keypad SPI 4-digit LED display Countdown timer Programmable, multi-function peripheral device and operating system Octavius--advanced robotics experimentation platform L298 dual DC motor controller board Each fun, inexpensive Evil Genius project includes a detailed list of materials, sources for parts, schematics, and lots of clear, well-illustrated instructions for easy assembly. The larger workbook-style layout and convenient two-column format make following the step-by-step instructions a breeze. Make Great Stuff! TAB, an imprint of McGraw-Hill Professional, is a leading publisher of DIY technology books for makers, hackers, and electronics hobbyists.
30 BeagleBone Black Projects for the Evil Genius
Author: Christopher Rush
Publisher: McGraw Hill Professional
ISBN: 0071839291
Category : Technology & Engineering
Languages : en
Pages : 161
Book Description
Fiendishly Fun Ways to Use the BeagleBone Black! This wickedly inventive guide shows you how to program and build fun and fascinating projects with the BeagleBone Black. You’ll learn how to connect the BeagleBone Black to your computer and program it, quickly mastering BoneScript and other programming tools so you can get started right away. 30 BeagleBone Black Projects for the Evil Genius is filled with a wide variety of do-it-yourself LED, sensor, robotics, display, audio, and spy gadgets. You’ll also get tips and techniques that will help you design your own ingenious devices. Features step-by-step instructions and helpful illustrations Provides full schematic and breadboard layout diagrams for the projects Includes detailed programming code Removes the frustration factor—all required parts are listed along with sources Build these and other clever creations: High-powered LED Morse code sender RGB LED fader GPS tracker Temperature sensor Light level indicator Web-controlled rover Plant hydration system Sentinel turret 7-segment clock Display for sensor information Internet radio Imperial march indicator Intruder alert using Twitter API Lie detector Auto dog barker
Publisher: McGraw Hill Professional
ISBN: 0071839291
Category : Technology & Engineering
Languages : en
Pages : 161
Book Description
Fiendishly Fun Ways to Use the BeagleBone Black! This wickedly inventive guide shows you how to program and build fun and fascinating projects with the BeagleBone Black. You’ll learn how to connect the BeagleBone Black to your computer and program it, quickly mastering BoneScript and other programming tools so you can get started right away. 30 BeagleBone Black Projects for the Evil Genius is filled with a wide variety of do-it-yourself LED, sensor, robotics, display, audio, and spy gadgets. You’ll also get tips and techniques that will help you design your own ingenious devices. Features step-by-step instructions and helpful illustrations Provides full schematic and breadboard layout diagrams for the projects Includes detailed programming code Removes the frustration factor—all required parts are listed along with sources Build these and other clever creations: High-powered LED Morse code sender RGB LED fader GPS tracker Temperature sensor Light level indicator Web-controlled rover Plant hydration system Sentinel turret 7-segment clock Display for sensor information Internet radio Imperial march indicator Intruder alert using Twitter API Lie detector Auto dog barker