Structure and function in living systems
In this publication, we provide a wide variety of resources to enrich your content knowledge of the characteristics of living things, including their diversity, extinction, and evolution.
Fisheries Learning on the Web
FLOW is a comprehensive curriculum about the Great Lakes ecosystem with three core units: Food Web, Water and Fish. Geared toward upper elementary and middle school educators, standards-based lesson content features hands-on activities.
Area of a rectangle. Definition and formula
A web page and interactive applet showing the ways to calculate the area of a rectangle. The user can drag the vertices of the rectangle and the other points change automatically to ensure it remains a rectangle. A grid inside the shape allows students to estimate the area visually, then check against ...
Area of a trapezoid. Definition and formula
A web page and interactive applet showing the ways to calculate the area of a trapezoid. The user can drag the vertices of the trapezoid and the other points change automatically to ensure it remains a trapezoid. A grid inside the shape allows students to estimate the area visually, then check against ...
Median of a triangle
A web page and interactive applet illustrating the medians of a triangle. The applet shows a triangle where the user can drag the vertices to reshape it. As the triangle is being reshaped, the user can see the three median lines tracking the changes, and observe that that all three always intersect ...
Rectangle
A web page and interactive applet showing the definition and properties of a rectangle. The applet shows a rectangle where the user can drag any vertex. The other points then move in such a way that the figure remains a rectangle at all times. A control to hide the details allows a classroom discussion ...
Rhombus
A web page and interactive applet showing the definition and properties of a rhombus. The applet shows a rhombus where the user can drag any vertex. The other points then move in such a way that the figure remains a rhombus at all times. A control to hide the details allows a classroom discussion where ...
Rhombus area formula
A web page and interactive applet showing the ways to calculate the area of a rhombus. The user can drag the vertices of the rhombus and the other points change automatically to ensure it remains a rhombus. A grid inside the shape allows students to estimate the area visually, then check against the ...
Right triangle
An interactive applet and associated web page that demonstrate the three types of triangle: acute, obtuse and right. The applet shows a triangle that is initially right (one angle 90 degrees) which the user can reshape by dragging any vertex. There is a message changes in real time while the triangle ...
Similar Triangles
An interactive applet and associated web page that demonstrate the concept of similar triangles. Applets show that triangles are similar if the are the same shape and possibly rotated, or reflected. In each case the user can drag one triangle and see how another triangle changes to remain similar to ...
Tetragon
A web page and interactive applet illustrating the properties of a tetragon (4 sided polygon). The applet shows a tetragon where the user can drag any vertex to reshape the polygon. User can see that the interior and exterior angles are constant in a regular tetragon, but vary in an irregular version. ...
Thales theorem
A web page and interactive applet illustrating Thales Theorem (the diameter of a circle always subtends a right angle to any point on the circumference). The applet shows a circle where the user can rotate the diameter and a move a point on the circumference. The applet continuously shows the resulting ...
Trapezoid
A web page and interactive applet showing the definition and properties of a trapezoid. The applet shows a trapezoid where the user can drag any vertex. The other points then move in such a way that the figure remains a trapezoid at all times. A control to hide the details allows a classroom discussion ...
Triangle
An interactive applet and associated web page that introduce the concept of a triangle. The applet shows a triangle where the user can drag the vertices to reshape it. As it is being dragged a base and altitude are shown continuously changing. Demonstrates that the altitude may require the base to be ...
Triangle centroid
A web page and interactive applet demonstrating the concept of the centroid of a triangle. The applet shows a triangle where the user can drag the vertices around. The centroid and the median lines that generate it are continuously moved as the user drags the vertices. By experimentation the user can ...
Triangle Circumcenter
The applet shows a triangle which the user can resize by dragging any of its vertices. It shows the three perpendicular bisectors of the sides and the point where they intersect - the circumcenter. These track the changes in the triangle in real time. It shows that the circumcenter may lie outside the ...
Triangle circumcircle
An interactive applet and associated web page that demonstrate the properties of the circumcircle of a triangle. The applet shows a triangle where the user can drag the vertices to reshape it. The circumcircle (the circle that passes through all vertices) is continuously updated as the triangle is resized. ...
Triangle exterior angles
An interactive applet and associated web page that demonstrate the exterior angles of a triangle. The applet shows a triangle where the user can drag any vertex to reshape it. The exterior angles are shown and a running calculation shows that no matter how you change the triangle, the exterior angles ...
Triangle Incenter
A web page and interactive applet demonstrating the concept of the incenter of a triangle. The applet shows a triangle where the user can drag the vertices around. The incenter and the angle bisector lines that generate it are continuously moved as the user drags the vertices. By experimentation the ...
Triangle incircle
A web page and interactive applet demonstrating the concept of the incircle of a triangle - the largest circle the will fit inside a triangle. The applet shows a triangle where the user can drag the vertices around. The incircle is continuously adjusted as the user drags the vertices. By experimentation ...













