Freebookcentre.net's computer science section contains links to many technical books offered free online, either as html pages or downloadable pdfs. Books are arranged by subject: Data Structures and Algorithms, Compiler Design, Object Oriented Programming, Operating Systems, Computation Theory, Artificial Intelligence, and others.

Kibera, a poor community, in Nairobi, was a blank spot on the map until recently. This video from Penn State Public Broadcasting’s Geospatial Revolution shows how geospatial technology enabled residents to map resources to help their community.

The marine environment is unique and requires technologies that can use sound to gather information since there is little light underwater. The sea-floor is characterized using underwater sound and acoustical systems. Current technological innovations are allowing scientists to further understand and apply information about animal locations and habitat. Remote sensing and exploration with underwater vehicles allows scientists to map and understand the sea floor, and in some cases, the water column. In this lesson, the students will be shown benthic habitat images produced by GIS. These imaged will lead to a class discussion on why habitat mapping is useful and how current technology works to make bathymetry mapping possible. The teacher will then ask inquiry-based questions to have students brainstorm about the importance of bathymetry mapping.

Students measure the permeability of different types of soils, compare results and realize the importance of size, voids and density in permeability response.

This illustrated essay from A Science Odyssey Web site explains the science behind radio waves, including the role of electrons and electromagnetic fields.

Searching for things on the Internet can be like hunting for a needle in a large haystack. Just how large is the Internet?

Students learn about complex networks and how to use graphs to represent them. They also learn that graph theory is a useful part of mathematics for studying complex networks in diverse applications of science and engineering, including neural networks in the brain, biochemical reaction networks in cells, communication networks, such as the internet, and social networks. Students are also introduced to random processes on networks. An illustrative example shows how a random process can be used to represent the spread of an infectious disease, such as the flu, on a social network of students, and demonstrates how scientists and engineers use mathematics and computers to model and simulate random processes on complex networks for the purposes of learning more about our world and creating solutions to improve our health, happiness and safety.

Student groups use the Java programming language to implement the algorithms for optical character recognition (OCR) that they developed in the associated lesson. They use different Java classes (provided) to test and refine their algorithms. The ultimate goal is to produce computer code that recognizes a digit on a scoreboard. Through this activity, students experience a very small part of what software engineers go through to create robust OCR methods. This software design lesson/activity set is designed to be part of a Java programming class.

In this video segment adapted from the Massachusetts Institute of Technology, researchers in the Artificial Intelligence Laboratory working to engineer smarter robots are now building a machine that interacts socially with people.

Join the ladybug in an exploration of rotational motion. Rotate the merry-go-round to change its angle, or choose a constant angular velocity or angular acceleration. Explore how circular motion relates to the bug's x,y position, velocity, and acceleration using vectors or graphs.

Working as a team, students discover that the value of pi (3.1415926...) is a constant and applies to all different sized circles. The team builds a basic robot and programs it to travel in a circular motion. A marker attached to the robot chassis draws a circle on the ground as the robot travels the programmed circular path. Students measure the circle's circumference and diameter and calculate pi by dividing the circumference by the diameter. They discover the pi and circumference relationship; the circumference of a circle divided by the diameter is the value of pi.

This article discuss basic ecological concepts such as food chains and webs within the context of the tundra.

A realistic mass and spring laboratory. Hang masses from springs and adjust the spring stiffness and damping. You can even slow time. Transport the lab to different planets. A chart shows the kinetic, potential, and thermal energy for each spring.

Learn about position, velocity, and acceleration in the "Arena of Pain". Use the green arrow to move the ball. Add more walls to the arena to make the game more difficult. Try to make a goal as fast as you can.

Small molecules are chemicals that can interact with proteins to affect their functions. Learn about the structure and biological functions of various small molecules like sugar and caffeine. Also featured on the HHMI DVD, Scanning Life's Matrix: Genes, Proteins, and Small Molecules. Available free from HHMI.

Try the new "Ladybug Motion 2D" simulation for the latest updated version. Learn about position, velocity, and acceleration vectors. Move the ball with the mouse or let the simulation move the ball in four types of motion (2 types of linear, simple harmonic, circle).

Learn about position, velocity, and acceleration graphs. Move the little man back and forth with the mouse and plot his motion. Set the position, velocity, or acceleration and let the simulation move the man for you.

In this lesson, students will be amateur mycologists--collecting and analyzing various mushrooms. Through observation and discussion, students will gain knowledge of the basic anatomy of mushrooms, their life cycle, and their method of reproduction through spores. Students will learn to create spore prints of mushrooms and label and preserve their spore prints, just like a mycologist. Students also will learn that by comparing spore prints, they can identify different mushroom species.

Build your own system of heavenly bodies and watch the gravitational ballet. With this orbit simulator, you can set initial positions, velocities, and masses of 2, 3, or 4 bodies, and then see them orbit each other.

Students apply concepts of disease transmission to analyze infection data, either provided or created using Bluetooth-enabled Android devices. This data collection may include several cases, such as small static groups (representing historically rural areas), several roaming students (representing world-travelers), or one large, tightly knit group (representing urban populations). To explore the algorithms to a deeper degree, students may also design their own diseases using the App Inventor framework.