How Many Monarchs on a Branch?
Discussion of Challenge Question #1

Thanks to everyone for sending the great monarch math! We wish we had room for all your answers, but here are samples from Vermont and West Virginia:

"If one monarch weighs 500 mg, then a branch full of 15,000 butterflies would weigh 7,500,000 mg. Since there are 1000 mg. to a gram, that means the butterflies would weight 7,500 grams. This would mean they were 7.5 kilograms. A kilogram is the same as 2.2 pounds. So the butterflies weight 16.5 pounds."
Ashley at Ferrisburgh Central School
(
lthurfer@pop.k12.vt.us)

Dear Journey North,
We think that a branch of monarch butterflies weighs up to 7,500 grams, which is seven and a half kilograms. We used a T- chart to change the kilograms into pounds. The number of pounds was 16 and a half. Our T-chart looked like this-

 kilograms pounds 1 2.2 2 4.4 3 6.6 4 8.8 5 11 6 13.2 7 15.4 1/2 1.1 7 & 1/2 16.5

Mr. Phillips's Third Grade Class
Davisville, WV
(
jsphilli@access.k12.wv.us)

Other things that weigh as much as a branch full of monarch butterflies:

• A Thanksgiving turkey! say Avian and Ariel.
• South Park Elementary's Imagewriter II printer weighs 18 lb--or, 4/5 of a box of Ferrisburgh Central School's computer paper (which weighs 20 pounds).
• 2 gallons of water, a big house cat, or a large rock.
• And even some people! (Rod's little 1 year old cousin and, if Auriana's new 8 pound baby sister had a twin sister, together they would weigh about as much as a branch of monarch butterflies.)