Watch a reaction proceed over time. How does total energy affect a reaction rate? Vary temperature, barrier height, and potential energies. Record concentrations and time in order to extract rate coefficients. Do temperature dependent studies to extract Arrhenius parameters. This simulation is best used with teacher guidance because it presents an analogy of chemical reactions.

Add different salts to water, then watch them dissolve and achieve a dynamic equilibrium with solid precipitate. Compare the number of ions in solution for highly soluble NaCl to other slightly soluble salts. Relate the charges on ions to the number of ions in the formula of a salt. Calculate Ksp values.

Dope the semiconductor to create a diode. Watch the electrons change position and energy.

This activity is an investigation of free fall and projectile motion through a track and field situation.

Why do the lights turn on in a room as soon as you flip a switch? Flip the switch and electrons slowly creep along a wire. The light turns on when the signal reaches it.

An interactive applet and associated web page that demonstrate the concept of similar polygons. Applets show that polygons are similar if the are the same shape and possibly rotated, or reflected. In each case the user can drag one polygons and see how another polygons changes to remain similar to it. The web page describes all this and has links to other related pages. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

Algebra students need practice determining equations of lines given a pair of points, or the line parallel or perpendicular to a given line through a given point. This Demonstration, along with guiding worksheets or a teacher presentation, gives students a chance to see the relationships between these lines and points.

This simulation lets you see sound waves. Adjust the frequency or volume and you can see and hear how the wave changes. Move the listener around and hear what she hears.

In this simulation, students adjust the slider to increase or decrease the pitch of a sound. They can also manipulate the time scale. This is used in Lesson 5 of Unit 8.2 of the OpenSciEd curriculum.

In this simulation, students adjust the slider to increase or decrease the loudness of a sound. They can also manipulate the time scale. This is used in Lesson 4 of Unit 8.2 of the OpenSciEd curriculum.

Have you ever wondered what happens to the different stars in the night sky as they get older? The Star in a Box application lets you explore the life cycle of stars. It animates stars with different starting masses as they change during their lives. Some stars live fast-paced, dramatic lives; others change very little for billions of years. The app visualises the changes in mass, size, brightness and temperature for all these different stages.

Heat, cool and compress atoms and molecules and watch as they change between solid, liquid and gas phases.

In this simulation, you see, on the left, a picture of a box at rest on a table. You can apply a force to the box - note that you set the y-component and the x-component separately. On the right, you can see the full free-body diagram of the box. The free-body diagram shows the gravitational force exerted on the box by the Earth, the normal force exerted by the table, the force that you apply, and, if there is one, the static force of friction. Note that, on the free-body diagram, the force of gravity and the normal force have been shifted horizontally a little so they can be seen more easily. If there is a net force, that is also indicated.

The classic Stern-Gerlach Experiment shows that atoms have a property called spin. Spin is a kind of intrinsic angular momentum, which has no classical counterpart. When the z-component of the spin is measured, one always gets one of two values: spin up or spin down.

Explore stretching just a single strand of DNA using optical tweezers or fluid flow. Experiment with the forces involved and measure the relationship between the stretched DNA length and the force required to keep it stretched. Is DNA more like a rope or like a spring?

An interactive applet and associated web page that demonstrate supplementary angles (two angles that add to 180 degrees.) The applet shows two angles which, while not adjacent, are drawn to strongly suggest visually that they add to a straight angle. Any point defining the angle scan be dragged, and as you do so, the other angle changes to remain supplementary to the one you change. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

With this free online tone generator, students enter their desired frequency and press play. The tone generator plays four different waveforms. This is used in Lesson 12 of Unit 8.2 of the OpenSciEd curriculum.

The unit has two parts. In each, students dive into inquiry to answer the compelling questions:

1. Who are some of our closest tribal neighbors, and what have they been their lifeways since time immemorial?
2. Why do people explore, and how does this lead to expansion?

Part 1 is focused on the examination of the northwest and some of the original inhabitants. Through these questions students will learn about the culture of some of their closest tribal neighbors, the Spokane Indians. The final project for Part 1 is a cultural investigation display, in which students will show what they know about the culture of the Spokane Tribe.

In Part 2, Students will also learn about forces that brought change to the northwest: fur trade era and exploration. Students will ultimately learn about the Corps of Discovery and the Oregon Trail and know the impact each had on the west. Students will finish Part 2 with a timeline activity that will reflect choice and build upon student strengths according to their skill set.

Finally, a lesson on a Tribe of the Columbia Plateau is offered as an extension, but it is strongly recommended that students get to experience this lesson.

Note that the emphasis here is on the Spokane Tribe as one of our closest tribal neighbors. In no way is this an exhaustive study nor should the tribal cultures be generalized to other tribes of the region. We understand that each tribe in our region and North America was and continues to be unique in its culture, practices, lifeways, and traditions.

Addition of three Vectors, and displays resultant Vectors. Can drag the endPoints of the three different Vectors, but the resultant always starts at the origin.

This web page is an interactive physics problem on vector addition. The page explains the concept of breaking a vector into components and adding them together, and works through an example problem. The attached Java applet visualizes the problem. This is part of a collection of similar simulation-based student activities.