Lesson 4-7: Ocean Acidification (Science)

Engaging the Student (Entry Task) 

Checking for Understanding (exit ticket)

See specific lessons for timelines

Note: Some Woods Hole lessons require advanced prep. Be sure to read in advance!

Have students turn & talk about what they think ocean acidification means and what they've heard of it.

This is an issue that is brought up a lot in the media, but student may have a poor understanding of what the causes and effects of ocean acidification are.  They may have loose associations with it correlating to global warming. 

As students share out their thoughts, write them on the board or Post-Its and return to these preliminary ideas after the lessons.

Below are two curriculum pathways for learning about ocean acidification. One is designed by NOAA (5 lessons) and one designed by Woods Hole Oceanographic Institute (3 lessons). You can use either or both of these resources to suite the needs of your students.

The NOAA pathway is very data driven and the lesson objectives include students learning how to access and manipulate data

themselves. In the ideal case, students will access the Internet

individually or in groups in order to generate maps and graphs

using real data. 

The Woods Hole Curriculum is a series of three hands-on experiences to support national science education standards yet remain as low-cost and adaptable as possible. Most of the materials required here can be found at grocery stores and pet stores. By themselves, these labs won’t entirely explain ocean acidification to your students but will instead complement your own classroom presentation of the issue.

NOAA Ocean Acidification Curriculum

• Lessons & Locations:

1. Measuring Ocean pH (40 min, Pages 9-18): Students will learn how to use online tools to access false-color data maps and graphs of ocean pH data. Students will examine data maps and graphs to look for patterns and relationships that would explain variations in ocean pH.

2. The Ocean-Carbon Connection (40 min, Pg 19-32): Students will use online tools to access data graphs of ocean pH, sea surface temperature, and CO₂ data to find the driving factor behind ocean acidification.

3. Oceans & Carbonate Chemistry (40 min, Pg 33-44): Students will use online tools to re-create climate change model scenarios and examine effects of increased CO₂ on ocean acidity and carbonate saturation levels.

4. Aragonite Saturation & Marine Calcifiers (80 min, Pg 45-55): Students examine the relationship between aragonite saturation levels and the health of marine calcifiers. Students will use online data to support or disprove a simple hypothesis about increased atmospheric CO2 and the health of marine calcifiers, such as coral reefs.

5. Design Your Own Investigation (120 min, Pg 56-60): Students will design an investigation into ocean acidification using real data on conditions in the Caribbean study area. Students will use this real data to try to answer a research question of their choosing and then use their findings to evaluate, explain and prove (or disprove) their hypothesis.

Woods Hole Curriculum

• Lessons & Locations 

1. Is Seawater More Like Lemons or Bleach? ( 30-45 min, Pg 4-11): In this experiment, students research the pH of different types of water and compare their findings to the pH values of common household acids and bases)
2. Ocean Acidification in a Cup (30-45 min, Pg  12-20): In this experiment, students learn about alkalinity, which helps seawater resist changes in pH, and test the alkalinity of four different types of water. Students will then compare the responses of different waters to carbon dioxide gas.
3. I'm Melting! Seashells in Acid (20 minutes, Pg 21-22): Students observe a demonstration of mollusk shell strength after exposure to acidic conditions.

NOAA Curriculum:

Lesson 1

• Computer or overhead projector
• Map and graph image(s) saved to your computer
• Copies of Student Master

Lesson 2

• Computer or overhead projector
• Map and graph image(s) saved to your computer
• For Demo:
• container of tap water
• blue pH indicator,
• small piece of dry ice or a straw
• Copies of Student Master

Lesson 3

• Computer or overhead projector
• Access to Internet
• Copies of Student Master

Lessons 4 & 5

• Copies of Student Masters
• Student computers with access to Internet
• Spreadsheet software (opt)
• Graph Paper
• Ruler

Woods Hole Curriculum:

Lab 1, per group

• Artificial seawater (100 ml, recipe on Pg 3)
• Red Cabbage pH Indicator (100 ml, recipe on Pg 2) 
• Unflavored Seltzer Water (100 ml)
• Distilled Water (100 ml)
• Tap Water (100 ml) 
• 12-14 test tubes
• Test tube rack
• Sharpie
• pH indicator
• White paper (10 sheets)
• Aquarium water hardness test kit
• Labeled disposable pipettes (1 for each acid and base) 
• Labeled samples of acids and bases (100 ml each, 7-10 of those listed on Pg 4)

Lab 2, per group: 

• Red Cabbage pH Indicator, 100 ml
• Aquarium alkalinity test kit
• distilled water
• tap water
• seltzer water
• artificial seawater 
• test tubes
• test tube racks
• sharpie
• 18 sheets white paper
• 72 clear plastic cups
• 724 straws
• stopwatch

Lab 3, per class: 

• 500 ml white vinegar
• 1.5 L water
• 2 1L beakers
• Small, thin seashells (~4 per group)
• Heavy books