Lab 1a - Water absorption properties of clay minerals

The objective of this lab is to test the water absorption properties of some clay minerals and some other clay-sized material. The procedure will be to add water to the mineral powders until you can tell that there is more water than can be readily absorbed. Some samples might absorb several tens of millilitres, others not much more than a millilitre.

Weigh 10 g of each of 3 of the following samples into a 250 ml beaker, making sure to keep track of which is which. Fill the buret with tap water and slowly add water to one of the containers, a few drops at a time to begin with. Keep stirring until you have a smooth paste, and watch out for excess water - that is water that doesn't get absorbed by the powder. Record the amount of water that has been added when you have a smooth paste that will flow when you tip the beaker. Repeat with the other samples.

Compare your results with those of the others (by calculating the class average), and comment on their significance.

Lab 1b - Changes in the concentrations of greenhouse gases

The objective of this lab is to work with some data on the concentrations of several different atmospheric gases. The data sets are as follows:  

Download the data sets from the table below as spreadsheet files (Excel) . To download one of the xls files click on the file name.using the right-mouse button, and then select "save as" The file are:

(References for the various data sets are given at the bottom of this page.  You don't need to visit those websites.)

For this lab you should create plots showing the trends of the atmospheric levels and rates of change of these gases over the relevant time periods, and then comment on what you observe. You will save yourself a great deal of time if you can create the graphics by computer. If you are familiar with the use of spreadsheet software, such as Excel, Quattro or Lotus-123, you should be able to work out how to do that. Otherwise you will have to get some help to learn how to use a spreadsheet, or you can do it by hand. Your completed lab should include 8 graphs, as follows:

In order to do the annual change graphs (4 and 7) you will need to calculate the year-to-year change for each parameter. For example the change in CO2 for the year 1766 is calculated by subtracting the 1765 value from the 1766 value. It is simple and quick to do this operation in a spread sheet.

Each graph should be accompanied by a one-paragraph description and interpretation. The purpose of doing graph 1 (CO₂ since 1995) is to observe the month-to-month changes in CO₂ levels. In your commentary you should speculate on the origin of this pattern.

References for the data sets

CO₂: monthly carbon dioxide data from air at Mauna Loa Hawaii since 1959. (Source: Carbon dioxide information analysis center (CDIAC), http://cdiac.esd.ornl.gov/ftp/ndp001/maunaloa.co2)

CO₂: annual carbon dioxide data from air at Mauna Loa Hawaii since 1959 and from Greenland ice cores for the preceding 176 years. (Source: Carbon dioxide information analysis center (CDIAC), http://cdiac.esd.ornl.gov/ndps/db1009.html)

CH₄: Ice-core and atmospheric methane data extending back to 1008

CFC: averaged annual CFC-11 and CFC-12 data from Grim Point, Tasmania, for 1978 to 1998 (Source:: Carbon dioxide information analysis center (CDIAC), cdiac.esd.ornl.gov/ndps/alegage.html)