The rate of heat flow between two objects is proportional to their difference in temperature. One experiences this every day, with stoves, outdoor weather and touching things. If you touch something that's the same temperature as your hand, there's no heat flow at all. This model allows you to adjust the temperature difference between two objects and observe the graph of heat flow.

Heat flows through solids at rates measured by their conductivity. The rate of heat flow is also proportional to the thickness of the material. This model compares the rate of heat transfer between two objects when they are separated by walls of different thickness.

Experiment with conductivity in metals, plastics and photoconductors. See why metals conduct and plastics don't, and why some materials conduct only when you shine a flashlight on them.

Experiment with conductivity in metals, plastics and photoconductors. See why metals conduct and plastics don't, and why some materials conduct only when you shine a flashlight on them.

An interactive applet and associated web page that demonstrate the concept of congruent angles. Three angles are shown which always remain congruent as you drag any defining point on any angle. They all change together. This is designed to demonstrate that the angles are considered congruent even if they are in different orientations and the line segments making them up are different lengths. 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.

An interactive applet and associated web page that demonstrate the congruence of polygons. The applet presents nine polygons that are in fact congruent, but don't look it because they are reflected and rotated in various ways. If you click on one, it rotates and flips as needed, then slides over the top of another to show it is congruent. The web page describes how to determine if two polygons are congruent. 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.

An interactive applet and associated web page that demonstrate the concept of congruent triangles. Applets show that triangles a re congruent if the are the same, rotated, or reflected. In each case the user can drag one triangle and see how another triangle changes to remain congruent 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.

This active demonstration investigates the law of conservation of momentum using a person on rollerblades and a thrown medicine ball.

This simulation shows the difference between Constant Velocity vs. Constant Acceleration هذه المحاكاة تبين الفرق بين السرعه الثابته والتسارع المستمر في الفيزياء

The simulation shows five different motions in which objects experience constant acceleration, starting from rest. Although each motion is different, the underlying physics is the same. What features of the simulation reinforce the idea that the physics is the same?

An interactive applet and associated web page that show how to construct a 30 degrees angle with a compass and straightedge. The animation can be single-stepped or run as a continuous movie. 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.

An interactive applet and associated web page that show how to construct a 45 degrees angle with a compass and straightedge. The animation can be single-stepped or run as a continuous movie. 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.

An interactive applet and associated web page that show how to construct a 60 degrees angle with a compass and straightedge. The animation can be single-stepped or run as a continuous movie. 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.

An interactive applet and associated web page that provide step-by-step instructions on how to construct an equilateral triangle with a given side length using only a compass and straightedge. The animation can be run either continuously like a video, or single stepped to allow classroom discussion and thought between steps. 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.

An interactive applet and associated web page that provide step-by-step animated instructions on how to construct a line parallel to a given line through a given point off the line. The animation can be run either continuously like a video, or single stepped to allow classroom discussion and thought between steps. 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.

An interactive applet and associated web page that provide step-by-step animated instructions on how to construct the incenter of a triangle. The animation can be run either continuously like a video, or single stepped to allow classroom discussion and thought between steps. 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.

This activity describes the construction and use of a pneumatic cannon and free falling target used to teach the concepts of projectile motion in introductory physics.

If there are air leaks in a house, you might expect that their effect would be magnified on a windy day. The wind creates greater air pressure on the windward side of the building and forces air in through the leaks. At the same time, the pressure on the other side of the building is lowered, pulling air out through leaks. This model has a fan blowing against a building. Air motion is shown with arrows. Open and close the "windows" in the building and observe the results.

Convection refers to transfer of heat by a fluid material (such as air or water) moving from one place to another. The convection is forced if the fluid motion is caused by a fan or a pump while natural convection is the result of density differences.

Conduction of heat refers to the transfer of heat through a solid. Convection refers to the transfer of heat by a fluid material (such as air or water) moving from one place to another. Warm air is less dense than cold air, so it rises and cold air sinks. This is called natural convection. Air is constantly circulating indoors and outdoors, moving heat from one place to another. With this model you can compare how conduction and convection transfer heat.