**ERIC Number:**EJ915189

**Record Type:**Journal

**Publication Date:**2011-Feb

**Pages:**6

**Abstractor:**ERIC

**Reference Count:**3

**ISBN:**N/A

**ISSN:**ISSN-1072-0839

Virtual Data Collection for Real Understanding

Ozgun-Koca, S. Asli; Edwards, Thomas G.

Mathematics Teaching in the Middle School, v16 n6 p362-367 Feb 2011

A common activity--having students collect data to measure the radius and circumference of circular objects--can be given a new twist. These data can be viewed virtually using technology. A dynamic geometry environment coupled with the powerful capabilities of a spreadsheet can greatly enhance student learning. The activity in this article addresses these grades 6-8 tenets found in "Curriculum Focal Points," which state that students should be able to: (1) analyze tables to discern relationships; (2) use equations to describe relationships inherent in a table; (3) study areas and circumferences of circles; (4) identify the unit rate of the graph of a proportional relationship as the slope of the line; and (5) translate among verbal, tabular, graphical, and algebraic representations of functions. These suggestions can be explored in a technological environment where teachers and students use TI-Nspire[TM], GeoGebra, or The Geometer's Sketchpad[R]. Students collect data from a dynamic geometric construction and study the relationships among the radius of a circle, its circumference, and its area. Many technologies allow students to create and study dynamic geometric constructions by changing a part of the construction. The effects of that change in other parts of the same construction become clear for students to see. For instance, students can use a graphing calculator such as TI-Nspire with dynamic geometry features to grab and drag the radius of a circle to make it longer or shorter. However, in GeoGebra or Sketchpad, students would need to drag the endpoint of a radius. Students can also use the technology to quickly measure many circles, display these measurements, and observe the effect that changing the radius has on the circumference. These tools can also capture an approximation of the areas of the circles. A TI-Nspire-based activity sheet is included at the end of this article. (Contains 6 figures and 1 table.)

Descriptors: Graphing Calculators, Geometric Concepts, Geometry, Data Collection, Mathematics Instruction, Computer Uses in Education, Middle School Students, Secondary School Mathematics, Equations (Mathematics), Correlation, Graphs, Educational Technology, Computer Software

National Council of Teachers of Mathematics. 1906 Association Drive, Reston, VA 20191-1502. Tel: 800-235-7566; Tel: 703-620-3702; Fax: 703-476-2970; e-mail: orders@nctm.org; Web site: http://www.nctm.org/publications/

**Publication Type:**Journal Articles; Reports - Descriptive

**Education Level:**Grade 6; Grade 7; Grade 8; Middle Schools

**Audience:**N/A

**Language:**English

**Sponsor:**N/A

**Authoring Institution:**N/A