Modern Baseball Measurements
Baseballs weigh 5 to 5 ¼ ounces (142 to 149 grams) and are 9 to 9 ¼ inches in circumference.
Historical Baseball Measurements
Historically there was great variety in the weight, size, and shape of baseballs. It wasn’t until 1934 that professional leagues standardized the baseball.
Baseball Composition
Throughout history baseballs have been made from a wide variety of materials. Early baseballs were made of rubber from melted shoes wrapped in yarn and leather. Modern baseballs are made from a rubber coated cork, layers of yarn and an outer shell of cowhide.
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