Shape Science: PlayDoh Math
IntroductionHave you ever had fun making different figures or colorful creations using some PlayDoh? You can squish and stretch a single piece of PlayDoh to make all sorts of shapes. How does changing the shape of a piece of PlayDoh affect its volume? In this science activity, you will find out by investigating how a piece of dough’s shape affects its dimensions (length, width and height), and how these changes are related to the dough’s volume.
This activity is not appropriate for use as a science fair project. Good science fair projects have a stronger focus on controlling variables, taking accurate measurements, and analyzing data. To find a science fair project that is just right for you, browse our library of over 1,200 Science Fair Project Ideas or use the Topic Selection Wizard to get a personalized project recommendation.
BackgroundGeometry is the study of how to use math to describe and investigate different points, lines and shapes. A very basic threedimensional shape is the rectangular prism. A rectangular prism is a shape like a box or a book. It has six different sides, and if all six sides are the same length, then it is called a cube. A cube is the same shape as a die (i.e., one of a pair of dice), where each side is a perfect square. Cubes and rectangular prisms can be measured with the same geometrical formulas. A mathematical formula is the way a shape is described in geometry. A mathematical formula is a way to calculate different properties of a shape, such as its area and volume. Volume is a unique property of threedimensional shapes because threedimensional shapes take up space in three different directions: length, width and height. In this science activity, you will use PlayDoh to make a model of a rectangular prism, change one of its dimensions (height), and see what effect this has on the other two dimensions and on the object’s volume. Materials
Preparation
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Extra: In this activity you changed the length, width and height of a cube of dough, but you did not change the amount of dough you used. What would happen if the amount of dough did change? Would the volume also change? Try this activity again but this time add or take away some dough, forming the dough into a cube, and measure the dimensions of the shape. Extra: You could take your results from this activity and graph them. A good type of graph to use for this activity is a bar graph. Looking at your graph, how do the dimensions and volume change as the shape of the dough changes? Observations and ResultsAs you squished the cube of dough, did its height get smaller, its width and length get larger and its volume stay the same? In this activity, because the amount of dough used did not change (i.e., you did not add dough or take any away), the size, or volume, of the dough should have stayed the same. Because the mathematical formula for calculating the volume of a cube is length x width x height, and the volume stayed the same, as you squished the cube its height should have decreased (the cube was being flattened) while its length and width increased. For example, the initial cube may have had a length, width and height each equal to four centimeters. As the cube became squished, this may have changed to a length of five centimeters, a width of five centimeters and a height of 2.6 centimeters. While the shape of the dough changed, its volume remained the same (each of these shapes have a volume of approximately 65 cubic centimeters). More to Explore
CreditsTeisha Rowland, PhD, Science Buddies
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Key Concepts
Geometry, threedimensional, volume

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