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Sea Floor Spreading
TEACHER NOTES
MIDDLE GRADES SCIENCE NSPIRED
Science Objectives

Students will collect distance data between two continents with
the corresponding earth’s age to determine what is happening at
the Mid-Atlantic ridge.
Vocabulary
 ridge
 trench
 sea-floor spreading
 seismic
Tech Tips:

This activity includes screen
captures taken from the TINspire CX handheld. It is
About the Lesson


also appropriate for use with
In this lesson students will measure the distance between South
the TI-Nspire family of
America and Africa over a 120 million year time span. Students
products including TI-Nspire
will use graphical data to infer relative age of the sea floor.
software and TI-Nspire App.
As a result, students will understand that:
Slight variations to these

New sea floor is produced at the mid-ocean ridges.
directions may be required if

The oldest crust is found farthest from the mid-ocean ridges
using other technologies
besides the handheld.

TI-Nspire™ Navigator™
Watch for additional Tech
Tips throughout the activity

Send out the .tns file.
for the specific technology

Monitor student progress using Class Capture.
you are using.

Use Live Presenter to spotlight student answers.

Access free tutorials at
http://education.ti.com/calcul
Activity Materials

Compatible TI Technologies:
TI-Nspire™ Apps for iPad®,
ators/pd/US/OnlineTI- Nspire™ CX Handhelds,
TI-Nspire™ Software
Learning/Tutorials
Lesson Files:
Student Activity
 Sea_Floor_Spreading_Stude
nt.doc
 Sea_Floor_Spreading_Stude
nt.pdf
TI-Nspire document
 Sea_Floor_Spreading_.tns
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Sea Floor Spreading
TEACHER NOTES
MIDDLE GRADES SCIENCE NSPIRED
Discussion Points and Possible Answers
1. Students read the information on page 1.2 in the .tns file.
Move to page 1.3.
Have students answer question 1 in the .tns file, activity sheet, or both.
Q1.
Seismic activity along mid-ocean ridge systems is low and occurs at very shallow depths because
Answer: B. the new crust created here is thin and strain on the moving plates is less.
Move to page 1.4
2. After reading the instructions on page 1.4, students should close
the directions box by selecting
.
3. Students are instructed to click on the South American point and
drag the measure tool to the African point. Doing this will collect a
distance measurement.
4. Students use the time clicker to advance 10 million years towards
present time and repeat the distance measurement.
4. Students continue to collect distance measurements every 10
million years to present day.
Tech Tip: To access the Directions again, select Menu > 1: Earth
History> 1: Directions To close the directions window, students must
close box by selecting
..
Move to pages 1.5-1.11
5. On page 1.5 is a spreadsheet containing the distance measurements collected, followed by a
scatterplot. Students use this data to answer the following questions.
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Sea Floor Spreading
TEACHER NOTES
MIDDLE GRADES SCIENCE NSPIRED
Q2.
According the graph, as the age of the earth increases, the distance between South American and
Africa _______ .
(Remember: Present day is 0 years).
Answer: A. increases.
Q3.
According to this simulation, each plate is moving about
Answer: B. 33 km every million years
Tech Tip: Students may need help using the calculator app that is
embedded on page 1.8 for Question #3.
Q4.
New ocean floor is added at the
Answer: B. Mid-Ocean Ridge
Q5. What evidence from the graph supports the idea that new sea floor is being created?
Sample Answer: Student answers will vary; The age of the sea floor is youngest at the midocean ridge. The distance between the continents increased over time.
Q6.
The oldest sections of ocean floor are located next to the
Answer: B. Continental plate edges
Q7.
If new ocean floor is created at the Mid-Atlantic ridge, propose an explanation for why the earth’s
total crust is not increasing.
Sample Answer: Student answers will vary; While new crust is created at the mid-ocean ridges,
old crust is being destroyed somewhere else. The crust is continuously recycled at the trenches.
TI-Nspire Navigator Opportunities
Make a student a Live Presenter to illustrate show how to move the sliders. Throughout the activity,
monitor student progress. At the end of the activity, collect the .tns file and save to Portfolio.
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Sea Floor Spreading
TEACHER NOTES
MIDDLE GRADES SCIENCE NSPIRED
Wrap Up
When students are finished with the activity, retrieve the .tns file using TI-Nspire Navigator. Save
grades to Portfolio. Discuss activity questions using Slide Show.
Assessment

Formative assessment will consist of questions embedded in the .tns file. The questions will be
graded when the .tns file is retrieved. The Slide Show will be utilized to give students
immediate feedback on their assessment.

Summative assessment could consist of questions/problems on the chapter test or a
performance assessment involving students diagraming the motions of the earth’s plates
including labeling to show relative age near trenches and ridges.
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