Vectors versus scalars - Arctic Terns

 

Subject :  Physics

Date:

Teacher:

 

Title:  Direction is not just for birds – vectors vs. scalars

Central Concept:   In order to understand movement we need to understand distance and direction.

Learning Standards (National Science Education Content Standards) :

B.4 - Motions and forces

A.1.4 - Formulate and revise scientific explanations and models using logic and evidence

A.1.1 - Identify questions and concepts that guide scientific investigations

 

Essential Questions:

What is the difference between displacement and distance traveled?

Why is knowledge of the beginning and end points not enough to fully describe motion?

What is the difference between a scalar and a vector quantity?

Where is a scalar quantity adequate?

Where are vector quantities necessary?

 

Content and Skills:

Develop a mathematical understanding of distance and direction (B.4)

Characterization of motion, travel versus displacement (B.4)

Scientific inquiry and reading comprehension (A.1.4, A.1.1)

 

Learning Activities:

  1. Talk about bird migrations, birds must have a keen understanding of direction.  Some birds travel thousands of miles.  The Arctic Tern Migration Project showed that the arctic tern, a bird which weighs a little more than 4 ounces, travel an average of  70000 kilometers (44000 miles) per year.
  2. The distance between the Arctic and Antarctic destinations of the Arctic Tern  migration along the surface of the Earth, is about 13300 kilometers.  Therefore the round trip should be about 26300 kilometers.
  1. The total distance traveled by the Arctic Tern travel was measure to be 44000 kilometers
  1. The traveled distance is much greater than the distance displaced during the migration.  What does this mean?
  1. Show Arctic Tern migration map from the Arctic Tern Migration Project
  1. Define displacement distance
  2. Define travel distance
  3. Direction - why is the straight path not necessarily the “best”
  1. Brain storm session - Why would the birds travel that far?
  1. Looking for food?
  2. Lost?......
  1. A little more information:  Show map of prevailing winds from Prevailing Winds Wikipedia page
  1. Does this map help to explain the migration path?

 

Equipment / Materials:

Internet access – projector or computer lab

Wikipedia page on the Arctic Tern - http://en.wikipedia.org/wiki/Arctic_Tern

Wikipedia page on Prevailing winds - http://en.wikipedia.org/wiki/Prevailing_winds

The Arctic Tern Migration Project - http://www.arctictern.info

Expected Outcomes:

Students should:

  1. Know the difference between travel distance and displaced distance
  2. Understand that distance vectors are composed of distance and direction
  3. Begin to qualitatively understand that wind and wind direction play a role in the migration of the Arctic Tern.

Assessment / Assignment(s):

Homework:

Go to the Arctic Tern Migration Project - http://www.arctictern.info and answer the following questions:

  1. How long does it take for the Arctic Tern to migrate south?
  2. How about the northern migration?
  3. Why is the Southern migration slower?  (hint: Atlantic hot spot)
  4. What was the daily distance covered during the northern migration?