Students estimate the amount of wallpaper, paint, or carpet needed for a room, recognizing that measurements that are accurate to several decimal places are unnecessary for this purpose. Develop informal ways of approximating the surface area and volume of familiar objects, and discuss whether the approximations make sense. In conjunction with a science project, students need to find the surface area of their bodies. They then take the needed measurements and compute the surface areas of the relevant solids. Other students decide to use newspaper to wrap their bodies and then measure the dimensions of the sheets of newspaper used.
Students estimate the volume of air in a balloon as a way of looking at lung capacity.
Some of the students decide that the balloon is approximately the shape of a cylinder, measure its length and diameter, and compute the volume. They submerge the balloon, and read off how much water is left after the balloon is taken out. Students develop different strategies for finding the volume of water in a puddle. Express mathematically and explain the impact of the change of an object's linear dimensions on its surface area and volume. Students analyze cardboard milk containers to determine how the dimensions of the container affect the volume of milk contained in the carton and how the amount of cardboard used varies.