Math Words
Math words.com: Foci, Hyperbola
An explanation of what the foci is as it relates to hyperbolas. An accompanying illustration is also included.
TED Talks
Ted: Ted Ed: The Moon Illusion
Andrew Vanden Heuvel unravels the details of focus, distance, and proportion that contribute to the mystifying optical illusion. [4:09]
Exploratorium
Exploratorium: Water Sphere Lens
A discussion of how to make a magnifying lens exhibit using a water-filled flask and a light bulb. Consists of assembly instructions and a "To do and notice" section. Great for a teacher demonstration or a student project.
Other
Indiana University of Pennsylvania: Writing Center: Creating an Outline
The Indiana University of Pennsylvania Writing Center provides a tutorial lesson for "outlining" as a way of prewriting for an essay.
Math Words
Math words.com: Parabola
The definition for what a parabola is and an explanation of the difference between a parabola and u-shaped curve is given. Also provides illustrations of what a vertical and horizontal parabola look like.
Sophia Learning
Sophia: Parts of the Microscope: Lesson 2
This lesson will illustrate the different parts that make up a microscope, and explain how it works. It is 2 of 4 in the series titled "Parts of the Microscope."
Sophia Learning
Sophia: Parts of the Microscope: Lesson 3
This lesson will illustrate the different parts that make up a microscope, and explain how it works. It is 3 of 4 in the series titled "Parts of the Microscope."
Math Words
Mathwords: Directrix of a Parabola
A definition and example that shows what a directrix of a parabola is.
Windstream
Ojk's Precalculus Study Page: Parabolas
Good study tutorial about parabolas. There are examples of finding the equation of the parabola or the focal point and directrix that students can examine and attempt.
Science Struck
Science Struck: Real Life Examples of a Parabola
Explains what a parabola is and the vocabulary used to describe one and gives several examples of parabolas in real life.
Math Open Reference
Math Open Reference: Parabola
Learn about the three ways to define a parabola: Focus and Directrix, The Graph of a Function, and As a Conic Section. Examples are provided.
Math Words
Math words.com: Vertex, Parabola
The definition is given for what the vertex is. An example illustration is also given.
Other
Ma Ttours Definitions of Ellipse Terms Foci
Basic definitions are given for foci, focus, and other terms related to the focus (foci).
My Science Site
Bj's Science: Microscope Word Search [Pdf]
Site provides a helpful word search teachers can use to help their students familiarize themselves with a microscope and have some fun at the same time.
Curated OER
Directrix
MathWorld delivers a brief definition of a focus, with diagrams showing the focus of an ellipse, a parabola, and a hyperbola.
Curated OER
Educational Technology Clearinghouse: Clip Art Etc: Focus
A fire-place; a hearth; a brazier. The fire-place possessed a sacred character, and was dedicated among the Romans to the Lares of each family. Movable hearths, or braziers, properly called foculi, were frequently used. - Smith, 1873.