Bridges come in a wide variety of sizes, shapes, and lengths and are found all over the world. It is important that bridges are strong so they are safe to cross. Design and build a your own model bridge. Test your bridge for strength using a force sensor that measures how hard you pull on your bridge. By observing a graph of the force, determine the amount of force needed to make your bridge collapse.

A zip line is a way to glide from one point to another while hanging from a cable. Design and create a zip line that is safe for a hard-boiled egg. After designing a safety egg harness, connect the harness to fishing line or wire connected between two chairs of different heights using a paper clip. Learn to improve your zip line based on data. Attach a motion sensor at the bottom of your zip line and display a graph to show how smooth a ride your egg had!

Earthquakes happen when forces in the Earth cause violent shaking of the ground. Earthquakes can be very destructive to buildings and other man-made structures. Design and build various types of buildings, then test your buildings for earthquake resistance using a shake table and a force sensor that measures how hard a force pushes or pulls your building.

There are two types of catalysis reactions: homogeneous and heterogeneous. In a homogeneous reaction, the catalyst is in the same phase as the reactants. In a heterogeneous reaction, the catalyst is in a different phase from the reactants. This activity addresses homogeneous catalysis.

Explore a NetLogo model of populations of rabbits, grass, and weeds. First, adjust the model to start with a different rabbit population size. Then adjust model variables, such as how fast the plants or weeds grow, to get more grass than weeds. Change the amount of energy the grass or weeds provide to the rabbits and the food preference. Use line graphs to monitor the effects of changes you make to the model, and determine which settings affect the proportion of grass to weeds when rabbits eat both.

Explore the concept of evaporative cooling through a hands-on experiment. Use a wet cloth and fan to model an air-conditioner and use temperature and relative humidity sensors to collect data. Then digitally plot the data using graphs in the activity. In an optional extension, make your own modifications to improve the cooler's efficiency.

The Geniverse software is being developed as part of a five-year research project funded by the National Science Foundation. Still in its early stages, a Beta version of the software is currently being piloted in six schools throughout New England. We invite you to try the current Beta version, keeping in mind that you may encounter errors or pages that are not fully functional. If you encounter any problem, it may help to refresh or reload the web page.

This NetLogo model of leaf photosynthesis shows the macroscopic outcome of the reaction.

Meiosis is the process by which gametes (eggs and sperm) are made. Gametes have only one set of chromosomes. Therefore, meiosis involves a reduction in the amount of genetic material. Each gamete has only half the chromosomes of the original germ cell. Explore meiosis with a computer model of dragons. Run meiosis, inspect the chromosomes, then choose gametes to fertilize. Predict the results of the dragon offspring and try to make a dragon without legs. Learn why all siblings do not look alike.

This initial module from the GENIQUEST project introduces the dragons and the inheritance of their traits, then delves into meiosis and its relationship to inherited traits. Students examine the effects of choosing different gametes on dragon offspring, and learn about genetic recombination by creating recombination events to generate specific offspring from two given parent dragons. Students learn about inbred strains and breed an inbred strain of dragons themselves.

In this activity, students interact with 12 models to observe emergent phenomena as molecules assemble themselves. Investigate the factors that are important to self-assembly, including shape and polarity. Try to assemble a monolayer by "pushing" the molecules to the substrate (it's not easy!). Rotate complex molecules to view their structure. Finally, create your own nanostructures by selecting molecules, adding charges to them, and observing the results of self-assembly.

Video Description:  Simple machines are all around us and help make our work easier. When simple machines are combined, a compound machine is created. Learn about NASA's compound machine, the lunar crane, and the simple machines it contains to make work easier in Our World.  Video length:  4:17.NASA eClipsTM is a suite of online student-centered, standards-based resources that support instruction by increasing STEM literacy in formal and nonformal settings.  These free digital and downloadable resources inform and engage students through NASA-inspired, real-world connections.NASA eClips Our World videos (grades 3-5) help students understand the differences between science (the natural world) and engineering (the designed world).  These video segments supplement elementary learning objectives not only in science, technology, engineering and mathematics, but also in reading, writing, visual and performing arts.

Many factors influence the success and survival rate of a population of living things. Explore several factors that can determine the survival of a population of sheep in this NetLogo model. Start with a model of unlimited grass available to the sheep and watch what happens to the sheep population! Next try to keep the population under control by removing sheep periodically. Change the birthrate, grass regrowth rate, and the amount of energy rabbits get from the grass to keep a stable population.

How does energy flow in and out of our atmosphere? Explore how solar and infrared radiation enters and exits the atmosphere with an interactive model. Control the amounts of carbon dioxide and clouds present in the model and learn how these factors can influence global temperature. Record results using snapshots of the model in the virtual lab notebook where you can annotate your observations.

Investigate what makes something soluble by exploring the effects of intermolecular attractions and what properties are necessary in a solution to overcome them. Interactive models simulate the process of dissolution, allowing you to experiment with how external factors, such as heat, can affect a substance's solubility.

All cells, organs and tissues of a living organism are built of molecules. Some of them are small, made from only a few atoms. There is, however, a special class of molecules that make up and play critical roles in living cells. These molecules can consist of many thousands to millions of atoms. They are referred to as macromolecules (or large biomolecules).

Windmills have been used for hundreds of years to collect energy from the wind in order to pump water, grind grain, and more recently generate electricity. There are many possible designs for the blades of a wind generator and engineers are always trying new ones. Design and test your own wind generator, then try to improve it by running a small electric motor connected to a voltage sensor.