Measurement of length in the U.S. customary system is based on the inch, foot, yard and mile. Games with rulers and tape measures provide an interactive way of learning linear measurements. Send the kids out into the yard armed with a ruler or tape measure and a list of lengths, and challenge them to find objects of those lengths. A growth chart provides a way for kids to learn inches and feet; every couple of months, measure your child against the growth chart, and write his name on the height line. Another length activity involves showing a child just how tall a particular animal is. Cut a piece of yarn as long as the average height of the animal, and let your child unwind the yarn to see the the animal's size. This helps the child grasp the significance of measurements expressed in U.S. customary units.
Measurement of mass in the U.S. customary system is by avoirdupois weight, which includes grains, ounces, pounds and tons. Food scales provide a hands-on way for kids to learn the weight of different objects. Set out some grapes or small potatoes, and let them weigh out different amounts. Allowing your children to stand on a non-digital bathroom scale is another way of teaching them weight measurements; after they weigh themselves, have them hold different objects, and let them see how the weight changes with the addition of each object. At the grocery store, have your child weigh a certain number of apples or oranges on the grocery scale. Write the weight down, to be compared to the number on the digital scale at checkout.
Liquid volume is measured in fluid ounces, gills, pints, quarts and gallons under the customary system. Cooking is a convenient way to teach children about volume. Pull out measuring cups and spoons of different sizes, and show the kids how to use them to measure ingredients for a favorite recipe. Have them use both solid and liquid ingredients. Another volume activity children enjoy is a game in which they guess the volume of liquid that various items, such as a teacup, bowl, spoon and pot, can hold. After writing down their guesses, they fill the items with liquid to see how close their guesses were.
It is not uncommon for children to have a difficult time visualizing large units of measurement, such as miles, tons or gallons. For large liquid measurements, milk cartons or water bottles help kids comprehend the amounts. Using paper provides a visual comparison; cut different-sized pieces of paper, the largest piece representing a gallon, a piece a quarter of that size representing a quart, and so on. This activity also works for tons and miles as compared to smaller units; explain to the children that the paper representations are proportional to each other in size or distance.