Where
Was the Strongest Migration?
Use
Standard Units to
Compare Migration Rates
(Back
to this week's update.)
Summary
The four activities below help students understand that we must
use standard units of measurement to compare migration data. With standards
units, we can compare observations from one place from the next, one person
to the next, and one time to the next.
One standard unit is the migration rate which we measure in monarchs per hour (and/or monarchs per minute). To find the migration rate we need know two things:
- How many monarchs a person saw and
- How many hours (or minutes) a person was observing. (Many people forget to include this information with their observation reports!)
In addition to practicing the migration rates calculations in the activities that follow, encourage students to use standard units when they make their own monarch migration observations.
Online Practice Activity
Practice Activity
Data Sheet
Data Sheet
Teaching
Suggestion:
Follow these steps to introduce students to the concept of migration rates:
1. Consider the number of monarchs observed.
First, have students consider the information that people most commonly
provide, the number of monarchs they see. Write the following on the blackboard:
Observer A: I saw 80 monarch butterflies.
Observer B: I saw 79 monarch butterflies.
Ask students, Which observer saw more monarch butterflies? (Observer A.)
2.
Consider the length of the observation period.
Now add the following information about each observation:
Observer A: I was watching from 8 am to 4 pm.
Observer B: I was watching from 8 am to 9 am.
Ask students, Describe the new information that was added. Ask, What do we know that we did not know before? (We know how long each observer was watching, the observation period.)
Why is this new information important? What does it tell you about the migration in each place? (This is important because only if we know how much time a person was watching can we compare migration sightings from one time to the next and from one place to the next in a standardized way.)
3.
Calculate the length of each observation.
Now ask students, Exactly how long was each observer watching? Give
your answer in hours.
Observer A: 8 am to 4 pm = 8 hours
Observer B: 8 am to 9 am = 1 hour
4.
Explore the term, migration rate.
Intuitively, students will conclude that the migration was probably much
stronger where Observer B was watching. Help them find language to explain
this. Ask, Where would you rather have been watching monarch migration
with Observer A or Observer B? Explain why.
What words could we use to make the two observations easier to compare? Give students time to develop the concept of “monarchs per hour.” If they need help, give them a sentence starter such as: Observer A saw ___ in ___ but Observer B saw ___ in ___.
5. Calculate the migration rate (in monarchs per minute or hour).
| Migration Rate |
| 1)
Number of monarchs and |
- Observer A saw 1 monarch per hour.
- Observer B saw 79 monarchs per hour.
6.
Practice!
The following two activities give students a chance to practice calcluating
the "migration rate."
- Online Practice Activity: Monarchs per Minute
- Practice Activity: Migration Rate Math
7.
Real-world Applications: Who Will See the Record Flight This Fall?
Review
this fall's actual observations and collect the most impressive fall flights.
Record them on this data sheet. Predict where the strongest migration
will occur—then see what actually happens!
- Migration Records: See database, migration maps and weekly updates
- Datasheet: Who Will See the Record Flight This Fall?
- Datasheet: My Migration Rates
8.
Challenge students to look at data carefully.
While reviewing observations reported on the migration
maps ask students:
- Which observations are the most valuable?
- Which observations leave you with questions?
- Can you find observations that are missing information you need in order to calculate the migration rate? If so, what information is missing?
