The Earth we’re standing on is a huge ball zooming through space. It’s 8,000 miles wide, giving it almost 200 million square miles of area! (Your whole town might be less than 10 square miles). So our friend Evan K., asked, which one does Earth have more of, snow or trees? and has drawn a Star Wars clone trooper thinking about it. Well, more than 2/3 of Earth is covered by water. That leaves about 57 million square miles of land. Of that, scientists have used photos from “satellites” in space to map our forests. They found that trees cover about 3/10ths of all land, or 17,200,000 square miles (17.2 million). Meanwhile, people who study the weather have found that 17,800,000 million square miles of land have snow cover. So it’s almost a tie!
Wee ones: Which weighs more, 2 pounds of snow or 5 pounds of wood?
Little kids: A 1-foot square of snow 10 inches deep can weigh 10 pounds! If you shovel 5 square feet, what numbers do you say to count up the weight in 10s? Bonus: To compare, a 50-foot pine tree weighs about 2,000 pounds (2 thousand). If a tree twice as tall weighs twice as much, how much does it weigh?
Big kids: If each snowstorm brings 5 inches of snow, how many snowstorms would it take to pile the snow taller than you? Bonus: A thousand millions is called a “billion.” If Canada has 1 million square miles of forest with 2,000 (2 thousand) trees per square mile, how many trees do they have?
Wee ones: The 5 pounds of wood.
Little kids: 10, 20, 30, 40, 50. Bonus: 4,000 pounds (4 thousand).
Big kids: Different for everyone…find the biggest multiple of 5 less than your height in inches, then add 1 more set of 5. Bonus: 2 billion trees, or 2,000,000,000 (9 zeroes).
And thank you Evan for the cool question and awesome drawing!
Laura Bilodeau Overdeck is founder and president of Bedtime Math Foundation. Her goal is to make math as playful for kids as it was for her when she was a child. Her mom had Laura baking before she could walk, and her dad had her using power tools at a very unsafe age, measuring lengths, widths and angles in the process. Armed with this early love of numbers, Laura went on to get a BA in astrophysics from Princeton University, and an MBA from the Wharton School of Business; she continues to star-gaze today. Laura’s other interests include her three lively children, chocolate, extreme vehicles, and Lego Mindstorms.