by Deborah Newton

SUBJECT AREA: Math: Measuring Length, Area, and Perimeter


COST: $99.00 School Edition; $180.00 Lab Pack (5)


NOTABLE SYSTEM REQUIREMENTS: Macintosh: System 7 or later. Windows: minimum 486, Windows 3.1 or later, sound card recommended.

DESCRIPTION: Unlocking Measurement provides an opportunity for students to explore measurement concepts in a friendly, non-threatening environment. From the Main Menu students select the "Mat" on which they would like to work by clicking on the large, well-spaced buttons labeled Length, Area, or Area and Perimeter.

When the Length mat is selected, students can choose to compare length or measure length. The Length Compare mat permits students to add up to three colorful objects which they can then move around to compare their relative sizes and resize them. Clicking on the Reporter Tool button and then on one of the objects signals Marlu, the kangaroo, to tell how the length or height of that object compares to the other objects. Selecting the Length Measure mat allows students to measure items on the mat with a variety of non-standard units including paper clips, marbles, popcorn, and watermelons. (How many paper clips long is that worm?) A Notepad area is provided with all mats in the program so that students may also write about their work.

Selecting the Area mat presents a similar choice between comparing and measuring. Students place up to three of the same shapes on the mat. The Area Measure mat allows students to select non-standard units to measure objects - ladybugs, flowers, postage stamps, and more. If students opt for the Grid Mode, a background grid is displayed, and all the units that fit entirely within the shape are highlighted. In the Stamp Mode students can stamp units, one by one, onto the mat and into the shape.

The Area and Perimeter button brings students immediately to a mat displaying a 220 cell grid on which they can create shapes in any of four colors. A Paint Tool lets students "paint" shapes by clicking on as many contiguous cells as they wish; the program will not allow them to paint ineligible cells. This activity offers a Reporting Window which displays the numbers corresponding to the area and perimeter of the painted shapes. This display is dynamic and changes rapidly to reflect students' paintings so they receive immediate feedback about their shapes. When the Reporting Window is closed students can figure out the area and/or perimeter, record their results in the Notepad area, and then open the Reporting Window to check their work.

Three games are also included for measurement-related breaktaking: Lights On, Tight Fit and Eleven High.

STRENGTHS: Speech feedback enables early learners and non-readers to explore and learn independently. Users can elect to have Marlu speak either English or Spanish and onscreen text is displayed in the language of choice. Providing a conveniently displayed Notepad area encourages students to write about their discoveries, and when they print a mat, the Notepad text is printed as well.

WEAKNESSES: In the Area Measure mat, when Grid Mode is selected, only those non-standard units that lie completely in the shape are highlighted. Most of the shapes will contain numerous partial units that are not highlighted and this may cause some confusion. Students may need help recognizing that the entire enclosed space is the area of the shape, not just the highlighted portion.

SUMMARY: This program offers the opportunity to explore measuring length and area with non-standard units in an appealing and engaging fashion. With the click of a mouse button students can manipulate onscreen items to compare and measure length and area, and can paint shapes to learn about area and perimeter. Learning is facilitated and reinforced by the speech feedback available with the Reporter Tool. The readily available Notepad encourages students to think and write about their work. Unlocking Measurement is an excellent alternative to manipulatives for children who have physical disabilities.


Unlocking Measurement 3-6: linear and angle measurements, relationships among area, perimeter, segment lengths, and angles.

Unlocking Whole Numbers K-2: base-ten clocks, counters, coin recognition, hundred chart, sorting, fact families, addition, subtraction, place value, number patterns.

Unlocking Whole Numbers 3-5: introduces multiplication and division to the concepts in Unlocking Whole Numbers (K-2).

Unlocking Probability K-2: flipping coins, rolling cubes, spinning tops, and drawing marbles, graphs, and charts.

Unlocking Probability 3-6: prediction and interpretation of probability experiments.

Unlocking Geometry K-2: create patterns and pictures, develop spatial sense, learn about geometric relationships.

Unlocking Geometry 3-6: shape and pattern construction, relationships among geometric shapes, symmetry.

Unlocking Fractions & Decimals 3-6: fractions, ratios, decimals, proportions.

Deborah Newton is a graduate student in the Department of Special Education at The College of New Jersey.

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