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Project

1-Wire Weather Station

The weather station in this project is quite basic, measuring only temperature, pressure, and humidity, but it may be easily expanded to measure other weather components, such as wind speed and rainfall. The design is based on using a series of…

Project

3D Floor Plan

Floor plans show walls, windows, doors, and other features of a room or building. Architects and engineers use them to study spatial relationships and describe their designs. Typically, floor plans are rendered as two-dimensional drawings.In this…

Project

3D Skull Candy Mold

Whether preparing for Halloween or just a regular day, you can make skull-shaped edibles from this project's 3D candy mold. Like many molds, this one is a hollow container into which you can pour water or hot liquids, such as gelatin, chocolate, or…

Project

3D Spur Gear

A spur gear is a common toothed wheel that works with other wheels in a set to adjust the speed, power, or direction of a complex machine. It's found in many everyday devices, such as electric screwdrivers, washing machines, and mechanical clocks…

Project

3D Terrain Map

Terrain maps are physical models that give you an at-a-glance overview of landforms. Architects, builders, and engineers often use these types of maps to provide context to proposed building designs. In this project, you'll create a layered…

Project

3x3x3 LED Cube

LEDs (light-emitting diodes) are rectifying semiconductor devices that convert electrical energy into electromagnetic radiation. You can use these devices to create a 3-dimensional light display. LED cubes require some care and good soldering skills…

Project

Arduino Oscilloscope

An oscilloscope is a device that allows you to see an electronic signal so that it appears as a waveform. Traditional oscilloscopes work by amplifying a signal to control the position of a dot on the y-axis (vertical axis) of a cathode-ray tube…

Project

Chatbot, an Artificially Intelligent Microcontroller

The term "Chatbot" is used for a computer or computer program that is made to emulate some form of human intelligence through conversation. In this project, you will learn how easy it is to make a specific microcontroller—an Arduino™ Uno—seem as…

Project

Heart-Rate Monitor

This project uses a sensitive light-detecting resistor to detect small changes in the light beaming through your finger as your blood pumps through tiny arteries in the finger. This device is not the same as the heart-rate monitors typically used in…

Project

Jumbo Foam Glider

This project takes you through the steps to build, launch, and fly a foam glider in sustained and controlled flight. Control in flight is achieved by modifying the wind the glider flies through with a large cardboard sheet (paddle). If this is your…

Project

Laser-Grid Intruder Alarm

This is a working alarm. It uses a laser beam that bounces between mirrors attached to two walls that face each other. The figure to the right has been digitally edited to show the path of the beam. When the beam is broken, a buzzer sounds.This…

Project

Levitation Machine

This project allows you to use electromagnetic levitation to suspend a globe of the world above a surface. The "globe" is actually a table tennis ball painted to look like a globe. Keeping it in place requires careful control of electrical current…

Project

Light and Temperature Logger

Environmental research often involves the use of data loggers to record data at regular intervals over a period of time. Most data loggers are based on digital processors, and can be fairly expensive, but you can build your own. This project uses a…

Project

Pulse Generator Circuit

A pulse generator circuit is an important building block for many electronic projects, such as the heart of a digital clock. Its purpose is basically to switch an output on and off for as long as the circuit is activated. Sometimes, these circuits…

Project

Text-Controlled RGB LED

A red, green, and blue (RGB) light-emitting diode (LED) is a useful electronic component that can produce visible light in a variety of colors. This is done by varying the intensity of the light output of the three different color LED elements (red,…

Project

Theremin-like Instrument

A theremin is a musical instrument developed in the 1920s by the Russian inventor, Léon Theremin. It was one of the world's first electronic musical instruments. The original invention used radio-frequency electronics and a pair of antennae. By…

Project

Tumblewing Walkalong Glider

This project takes you through the steps to build, launch,and fly a paper airplane (glider) in sustained and controlled flight. Control in flight is achieved by modifying the wind the glider flies through with a large cardboard sheet or foam board…

Project

Ultralight Foam Glider

This project takes you through the steps to build, launch, and fly an ultralight foam glider in sustained and controlled flight. Controlled flight is achieved by modifying the wind the glider flies through with a large cardboard sheet, or paddle.The…

Project

White-Noise Generator

White noise is a smooth hiss consisting of all audio frequencies played back at random simultaneously. Because your ears cannot "lock" onto any specific frequencies or patterns in white noise, this device has the effect of shutting off your ears to…

Project

Wind Lantern

In this project, you will build a small, vertical-axis wind turbine, or VAWT for short. VAWTs are not as efficient as their horizontal-axis cousins, but they are better suited to urban environments where wind can come from different…

Project

Constant-Speed Vehicle

Everything in the universe is in motion. One basic, yet important, type of motion is constant-speed motion. This project takes you through assembly of a model battery-powered vehicle that moves at a constant speed. This particular vehicle is built…

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from article Breadfruit

Breadfruit (Artocarpus altilis), showing the rounded (or elliptic) fruit and the cylindrical staminate flower cluster. (Photo courtesy of Forest and Kim Starr)

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from article Island biogeography

Equilibrium number of species (Sequilibrium) is determined by the intersection of the immigration ( I ) and extinction ( E ) rate curves. P is the maximum number of species in the source pool.

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from article Robotics

A dexterous humanoid robot (robonaut) built at the NASA Johnson Space Center in Houston, Texas, USA to work alongside humans in space. (Credit: NASA)

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from article Robotics

A model for the selective compliance assembly robot arm (SCARA). It has 3 links. Horizontal links move sideways and the third (vertical) link moves up and down. It shown here with a drill, a chuck, and drill bit. (Credit: Richard Pasala)

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from article Robotics

The right hand of a NASA robot grasping a hook. The robot's hands closely mimics the human hand in order to use tools and handholds designed for astronauts. (Source: NASA)

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from article Robotics

Six-legged walking robot. (Odetics)

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from article Isotope

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from article Isotope

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from article Notch signaling

Notch-ligand interactions. Two Notch ligands, Delta and Serrate, are shown on the signal-sending cell (left). These ligands are distinguished by differing numbers of EGF-like repeats (indicated by the light boxes) and an extracellular cysteine-rich…

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from article Optical flat

Optical flat being used to determine flatness of seal ring. Interference bands on the seal ring face show lines of constant depth. (Van Keuren Co.)

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from article Optical flat

Measurement of height of sphere determined by means of gage blocks and optical flat. 1″ = 25.4 mm.

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from article Wilkinson Microwave Anisotropy Probe

Wilkinson Microwave Anisotropy Probe (WMAP) spacecraft. (Courtesy of NASA/WMAP Science Team)

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from article Wilkinson Microwave Anisotropy Probe

WMAP sky-scan strategy. (a) Location of the satellite relative to the Earth and Sun (not to scale), and the orientation of the satellite and of the lines of sight to the spots on the sky focused by the primary reflectors, which continually changed…

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from article Wilkinson Microwave Anisotropy Probe

WMAP full-sky CMB anisotropy map. The microwaves captured in this picture from WMAP are from when the universe was 378,000 years old, over 13 × 109 years ago. It is a “baby picture” of the universe, equivalent to taking a picture of an 80-year-old…

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from article Composite material

NASA technicians inspecting the keel section of a PRSEUS (Pultruded Rod Stitched Efficient Unitized Structure). This is a new way for aircraft sections to be built by sewing together layers and rods of composite material. (Credit: NASA…

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from article Composite material

Specific properties of various materials.

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from article Composite material

Tensile strength, modulus, and elasticity of various fiber materials. UHMWPE = ultrahigh-molecular-weight polyethylene; SiC = silicon carbide.

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from article Composite material

Typical autoclave layup.

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from article Composite material

Typical layups for (a) resin transfer molding (RTM) and (b) vacuum infusion (VI).

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from article Folic acid

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from article Digenea

Diagrams of various adult types of digenean trematodes. (After R. M. Cable, An Illustrated Laboratory Manual of Parasitology, Burgess, Minneapolis, 1940)

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from article Digenea

Digenean trematode life cycle. (After R. M. Cable, An Illustrated Laboratory Manual of Parasitology, Burgess, Minneapolis, 1940)

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from article Hydroponics

Green- and red-leaf lettuce growing in a hydroponic vegetable garden on a bamboo fence. The pipes, which supply nutrients and water, are part of the hydroponic system. (Credit: Piyachok Thawornmat, Shutterstock)

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from article Hydroponics

Hydroponic techniques: (a) aerated standing culture; (b) flowing-solution culture with standing solution; (c) nutrient film technique; (d) aeroponics.

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from article Emerald