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.

This interactive, scaffolded activity allows students to build an atom within the framework of a newer orbital model. It opens with an explanation of why the Bohr model is incorrect and provides an analogy for understanding orbitals that is simple enough for grades 8-9. As the activity progresses, students build atoms and ions by adding or removing protons, electrons, and neutrons. As changes are made, the model displays the atomic number, net charge, and isotope symbol. Try the "Add an Electron" page to build electrons around a boron nucleus and see how electrons align from lower-to-higher energy. This item is part of the Concord Consortium, a nonprofit research and development organization dedicated to transforming education through technology. The Concord Consortium develops deeply digital learning innovations for science, mathematics, and engineering. The models are all freely accessible. Users may register for additional free access to capture data and store student work products.

This interactive activity helps learners visualize the role of electrons in the formation of ionic and covalent chemical bonds. Students explore different types of chemical bonds by first viewing a single hydrogen atom in an electric field model. Next, students use sliders to change the electronegativity between two atoms -- a model to help them understand why some atoms are attracted. Finally, students experiment in making their own models: non-polar covalent, polar covalent, and ionic bonds. This item is part of the Concord Consortium, a nonprofit research and development organization dedicated to transforming education through technology.

This 90-minute activity features six interactive molecular models to explore the relationships among voltage, current, and resistance. Students start at the atomic level to explore how voltage and resistance affect the flow of electrons. Next, they use a model to investigate how temperature can affect conductivity and resistivity. Finally, they explore how electricity can be converted to other forms of energy. The activity was developed for introductory physics courses, but the first half could be appropriate for physical science and Physics First. The formula for Ohm's Law is introduced, but calculations are not required. This item is part of the Concord Consortium, a nonprofit research and development organization dedicated to transforming education through technology. The Concord Consortium develops deeply digital learning innovations for science, mathematics, and engineering.

This concept-building activity contains a set of sequenced simulations for investigating how atoms can be excited to give off radiation (photons). Students explore 3-dimensional models to learn about the nature of photons as "wave packets" of light, how photons are emitted, and the connection between an atom's electron configuration and how it absorbs light. Registered users are able to use free data capture tools to take snapshots, drag thumbnails, and submit responses. This item is part of the Concord Consortium, a nonprofit research and development organization dedicated to transforming education through technology.

In this interactive activity, learners explore factors that cause atoms to form (or break) bonds with each other. The first simulation depicts a box containing 12 identical atoms. Using a slider to add heat, students can see the influence of temperature on formation of diatomic bonds. Simulations #2 and #3 introduce learners to reactions involving two types of atoms. Which atom forms a diatomic molecule more easily, and why? The activity concludes as students explore paired atoms (molecules). In this simulation they compare the amount of energy needed to break the molecular bonds to the energy needed to form the bonds. This item is part of the Concord Consortium, a nonprofit research and development organization dedicated to transforming education through technology.

In this interactive activity, learners build computer models of atoms by adding or removing electrons, protons, and neutrons. It presents the orbital model of an atom: a nucleus consisting of protons and neutrons with electrons surrounding it in regions of high probability called orbitals. Guided tasks are provided, such as constructing a lithium atom and a carbon-12 atom in the fewest possible steps. The activity concludes with a model for building a charged hydrogen atom (an ion). Within each task, students take snapshots of their work product and answer probative questions. This item is part of the Concord Consortium, a nonprofit research and development organization dedicated to transforming education through technology.

Elementary grade students investigate heat transfer in this activity to design and build a solar oven, then test its effectiveness using a temperature sensor. It blends the hands-on activity with digital graphing tools that allow kids to easily plot and share their data. Included in the package are illustrated procedures and extension activities. Note Requirements: This lesson requires a "VernierGo" temperature sensing device, available for ~ $40. This item is part of the Concord Consortium, a nonprofit research and development organization dedicated to transforming education through technology. The Consortium develops digital learning innovations for science, mathematics, and engineering.

Explore how populations change over time in a NetLogo model of sheep and grass. Experiment with the initial number of sheep, the sheep birthrate, the amount of energy sheep gain from the grass, and the rate at which the grass re-grows. Remove sheep that have a particular trait (better teeth) from the population, then watch what happens to the sheep teeth trait in the population as a whole. Consider conflicting selection pressures to make predictions about other instances of natural selection.

This resource consists of a Java applet and expository text. The applet is a simulation of the coupon collector problem, which consists of sampling from the first m positive integers, with replacement, until k distinct values are obtained. The parameters m and k can be varied. The random variable of interest is the size of the sample.

This resource consists of a Java applet and expository text. The applet is a simulation of the standard casino craps game. The random variables of interest are the winning under various bets.

This resource consists of a Java applet and expository text. The applet simulates rolling n dice. The random variables of interest are the sum of the scores, the maximum score, the minimum score, and the number of aces. The number of dice and the probability distribution that governs the dice can be specified. The applet illustrates various distributions and the central limit theorem.

This resource consists of a Java applet and expository text. The applet simulates the rolling of n dice. The number of dice and the probability distribution that governs the dice can be specified.

This resource consists of a Java applet and expository text. The applet simulates the experiment of rolling a die and then tossing a coin the number of times shown on the die. The die distribution and the probability of heads can be specified. The applet illustrates a two-stage experiment.

The goal of this module is to explore the relationship between demographic characteristics and educational attainment. Frequencies and comparison of means will be used.

Use a series of interactive models and games to explore electrostatics. Learn about the effects positive and negative charges have on one another, and investigate these effects further through games. Learn about Coulomb's law and the concept that both the distance between the charges and the difference in the charges affect the strength of the force. Explore polarization at an atomic level, and learn how a material that does not hold any net charge can be attracted to a charged object. Students will be able to:

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.

Data set and map pertaining to expenditure per secondary school student for all countries as a percentage of their GDP per capita. The World Bank specifies expenditure per student as a World Development Indicator (WDI) -- the statistical benchmark that helps measure the progress of development.

Data set and map pertaining to expenditure per secondary school student for all countries as a percentage of their GDP per capita. The World Bank specifies expenditure per student as a World Development Indicator (WDI) -- the statistical benchmark that helps measure the progress of development.

Data set and map pertaining to expenditure per tertiary school student for all countries as a percentage of their GDP per capita. The World Bank specifies expenditure per student as a World Development Indicator (WDI) -- the statistical benchmark that helps measure the progress of development.