Description:
Ice core analysis is an effective tool for understanding climate over time and how it is changing. This lesson and inquiry based activities allow students to examine a simulated record of climate change. Through the study of ice core samples, students gain a greater understanding of the natural systems involved in climate change, the history of the Earth’s climate, and the human influences on climate today.
The lesson begins with a 10 min TED videoclip on ice cores. It includes a wet lab activity (Using Ice Cores to Collect Evidence of Past Climates) and a dry lab activity where studemts analyze data patterns from an actual ice core (Analysis of Ice Cores from Antarctica and Greenland).
Standards Alignment:
» Add a Curriculum Benchmark Alignment!
21st Century Skills: (learn more)
No 21st Century Skill alignments have been added for this activity yet.
Tools & Materials:
For each group of 2-3 students:
1 ice core (in a test tube)
1 single sided razor blade (or scalpel)
wide range pH paper
paper towel
magnifying glass
flashlight – optional – to test for Tyndall effect in particulate layer
Computers/laptops for students (individuals or pairs) for the 3rd part of the activity.
Time Required:
a minimum of one 75 minute period
Process:
1. (5 min) I like to begin this class by coming in dressed in full winter gear carrying in the ice cores. (I peel off the layers: hat, scarf, outer shell, fleece, sorrels, etc.) As I do this, I tell the students that I really go to the ends of the earth to make their learning profound – and say that I just got back from Antarctica where I was picking up their lab materials for today. I like to encourage my students to appreciate me Although the students see through the story right away, it’s fun to pretend.
2. 10 min – TED talk by Lee Holtz
3. 30 min – Using Ice Cores to Collect Evidence of Past Climates Activity
4. 30 min – Analysis of Ice Cores from Antarctica and Greenland (Dry Lab) Activity
Evaluation Rubric:
Mark breakdown is given on student lab sheet, “Using Ice Cores to Collect Evidence of Past Climates.”
Student Prompt:
See attached student instruction sheets:
• Using Ice Cores to Collect Evidence of Past Climates
• Analysis of Ice Cores from Antarctica and Greenland (Dry Lab)
Teacher Notes:
1. The attached article from Science Teachers, “Ice Core Investigations,” is excellent backgrounder for teachers.
2. Preparing the “ice cores”
a. Begin this a week prior to their use. Ice cores do not have to be identical – it will add variety to the activity if several different patterns of ice layers are used. Teachers should record each layer sequence they create and number them as a cross reference for evaluating student results.
b. The ice cores are made by creating alternating layers of ice in test tubes. It’s important that each layer freezes before the next one is added. Each core should have a minimum of four layers and a maximum of 6 layers.
c. Use large test tubes (e.g. 18 mm x 150 mm) for this rather than the typical size test tube.
d. Have 2 large (600 – 1000 mL) beakers of water prepared,
i. Beaker X, a typical year, could be normal tap water with enough blue food colouring to turn it a pale blue. Check the pH and adjust it so that it is close to neutral.
ii. Beaker Y, represents water from a year with high CO2 levels. It should be tap water brought down to a pH of 5 or below. I’ve found that sulphuric acid is far more efficient than vinegar for this. Let this water remain clear (no food colouring).
e. Set the test tubes in either a large test tube rack or a beaker so that they remain vertical while in the freezer. Number the test tubes and keep track of the sequencing of the layers that are added to each tube.
f. The following instructions outline how to make a single ice core. When making a class set remember to vary the number and order of layers suggested below.
o pour in enough water X to fill a test tube about 1/8th full. It is not necessary to be exact, nor is it necessary that all test tubes have exactly the same volumes.
Theory: Normally, polar air is very cold – therefore dry. Reference to the Particle Theory helps explain this very well. Snowfall in polar regions is not heavy.
o Place the test tube in the freezer and allow the water to freeze thoroughly before adding a weak acid Y layer.
o The layers of weak acid should be between 1.5 and 2 times as thick as the Y water layers.
Theory Thicker layers represent warmer time periods. Increased temperatures allow polar air to become more humid, thereby holding more water. Thus, more snow falls in those years. The dry lab shows that there is a strong positive correlation of increased temperature with increased CO2 concentrations. Increased concentrations of CO2 result in acidic precipitation; the CO2 reacts with H2O to form carbonic acid. CO2 may come from many sources such as volcanoes and human activities.
o For one or more of the acidic layers, remove ~250 mL of the weak acid into a separate beaker and stir in some ash (made by burning a piece of newspaper – about ¼ of a page). Crumble the burned paper to make sure there are minute pieces of ash. Filter the mixture through a coffee filter to remove the largest pieces – which will just sink to the bottom and generate confusion. This layer may or may not appear noticeably grey. Students can use magnifying glasses to look for particles and/or shine light from a flashlight through the ice layer (or possibly the water). Some Tyndall effect should occur.
Theory: Large volcanic eruptions spew ash into the atmosphere as well as multiple gases – including CO2. Not only can this material seriously disrupt air traffic, as with the Eyjafjallajokull volcano eruption in April 2010, but the ash can remain in the stratosphere temporarily blocking some incoming solar radiation. While the affect of a major volcanic eruption is often a short term (1-3 years) overall average drop in global temperatures NASA (Wolfe, 2000) has shown that the subsequent winter is warmer as a result of the aerosols released by the eruption staying in the stratosphere. These sulfate aerosols act as greenhouse gases since they appear to block more of the long wave radiation from leaving the troposphere. These aerosols can remain in the stratosphere for up to 3-4 years.
Result: the core section will be acidic (from the sulphuric acid formed from the sulphur dioxide reacting with water vapour) and thicker (due to the warmer air being able to hold more water vapour).
3. The attached labs contain multiple questions and dry lab activities. Keep the ones that are most useful for your students and delete the others.
• Using Ice Cores to Collect Evidence of Past Climates
• Analysis of Ice Cores from Antarctica and Greenland (Dry Lab)
Attachments:
• Ice Core Investigations
• Using Ice Cores to Collect Evidence of Past Climates
• Analysis of Ice Cores from Antarctica and Greenland (Dry Lab)
|
Home
TIGed
