Journey North Gray Whale Spring 2006

Discussion of Challenge Question #3

Mom and Calf
Photo Mike Hawe

Last time we said gray whales normally travel at about 3-5 miles per hour (4.8-8.1 km/hr). We asked: “If a gray whale and her calf swim more slowly, how long do you estimate their journey takes if they swim a total of 6,000 miles from Mexico to Alaska?”

Hooray for all the students who put good thinking and calculating into this challenge! Note that they use words like "about" and "estimate," showing that the answer is just a best estimate based on what we THINK we know. They showed the steps in their process--which helps all of us see how it's done. If you were stumped, these students will lead the way! Take a look at their answers and you'll agree: OUTSTANDING!

"I multiplied 3 miles times the number of hours in a day - to make 72 miles. This is what an average whale could easily do in one day. Then we took 6000 miles and divided that by 72 to see how many days an average whale would need to swim that distance. That would be about 83 days. So, if the gray whale and her calf swim more slowly than that, they would take over 83 days! If they swim 2 mph, it would be 125 days."
Phoebe and Ruby. Grade 4, Ferrisburgh Central School (Ferrisburgh, VT)

"I think the whale and her baby travel at around 2.5 miles per hour since
they swim more slowly than the average whale. I multiplied by 24 since there are 24 hours in a day. This equals 60 miles per day. I divided 6000 miles (distance from Mexico to Alaska) by 60 miles per day and my answer would be that it would be around 100 days for the mother and calf to arrive in Alaska."
Lilly, Megan, and Kyle. Grade 6, Ferrisburgh Central School (Ferrisburgh, VT)

"We estimate that it will take 50 to 83 days and 8 hours to go from Mexico to Alaska. Whales travel between 3 and 5 miles per hour. From Mexico to Alaska is 6000 miles."

If they travel at 3 mph, 6000 miles divided by 3mph = 2000 hours. Since there are 24 hours in a day, 2000 hrs. divided by 24 = 83days & 8hrs.
If they traveled at 4mph, 6000 divided by 4 = 1500 hours.
1500 divided by 24 = 62 days & 12 hrs.
If they traveled at 5mph, 6000 divided by 5 = 1200 hours
1200 divided by 24 = 50 hrs.

Akash, Rup, Mohammad, Parth, Stephen, Alexis, Elizabeth, Brian, Louis, Rizwan, Ronny and Kenny. Grade 7, Iselin Middle School (Iselin, NJ)