 essential activity why do we care about mercury  getting ready materials library or internet access calculators handouts student prerequisites how to measure volume and square inches parts of a circle proportions averages ranges computer skills library skills time needed activity procedure some groups might need a warmup activity to get ready for some of the mathoriented questions within this activity here some important background concepts and conversions to go over with students if the reference sheet in the resource section below is not sufficient math warmup  convert the following  mass 13 kilograms kg to grams g milligrams mg micrograms mg nanograms ng 4560 ng to mg mg g kg volume 4589 ml microliters to ml l 076 l to ml ml distance 125 mm to cm m geometry  say you dug out a bunch of soil and put it in a bucket you dug out a square of soil 1 meter wide by 1 meter long you dug out 50 cm of soil how many cubic centimeters cm 3 do you have you want to know how much water it will take to fill up your hot tub the tub is a circle 3 meters in diameter and you want to fill it so there are 150 cm of water in the tub how many cubic centimeters of water will it take a handy conversion is that 1 cubic centimeter cm 3 1 ml how many liters of water would it take to fill the hot tub  chemical concentrations  you have 10 grams of a chemical in 5 liters of water what is the concentration in mg l milligrams per liter you have 2 mg of a chemical in 8000 milligrams of soil what is the concentration in mg g micrograms per gram how many micrograms are in a gram express this as a mathematical relationship what is the concentration of the chemical in the soil above in parts per million ppm and in parts per billion ppb  doing the activity this activity involves doing some library or internet research and then doing some calculations based on that research to answer some questions access to the internet or to the library will be essential the students should also have access to calculators the activity is built around having the students develop answers to a number of questions typically students will work together in small groups 23 students with different groups developing answers to different sets of questions some sets are more difficult than others so you may want to review them first and assign accordingly we suggest having the questions printed off in advance for distribution to the groups at the end of the activity the students will come back together to share what they have found what follows are some good sets of starting questions you might wish to add others some questions are more difficult or more involved than others so you may not want to use all of them with all students to get the students thinking about mercury you might begin with a discussion to elicit what they already know it is likely that they have heard something about the dangers of eating fish with mercury they may also be aware of the dangers associated with mercury in fluorescent bulbs thermostats and other electronic devices notions of scale are important to the work that the students will be doing one of the question sets asks students to calculate the number of boxcars required to hold a billion ping pong balls the answer is 306 a good sized train you might set up this exercise by asking studentsbefore they do the calculationto estimate the answer divide the class into groups and distribute the question sets across the groups tell each group that they are expected to prepare material for presentation to the rest of the class this presentation could take a number of forms if computers are available you might ask each group to put together a set of slides on the computer that includes pictures when that is relevant and that makes the calculations clear after the groups have had time to develop their answers and presentations have the groups present to the class as a whole this is a good opportunity to focus on issues of scale and on flexibility in moving from one kind of unit to another if this is a biology class it is also a good opportunity to spend a bit of time talking about the significance of organic mercury and in general about why molecules that contain carbon are special when it comes to life processes  question sets set 1 social implications what is minamata disease what happened in minamata what concentration of mercury in hair is considered to be normal for people in the us what concentrations were found in the people of minamata express this concentration in terms of parts per billion parts per million μg g and mg kg set 2 social implications what was the source of mercury poisoning in iraq in the early 1970s what kinds of mercury concentrations in human hair were involved express these concentrations in terms of parts per billion parts per million μg g and mg kg set 3 least difficult what is a typical mercury concentration for muscle tissue in swordfish how about freshwater bass express these concentrations in terms of parts per billion parts per million μg g and mg kg set 4 all students should know but chemistry teachers may want to take this further in terms of chemical interact tions in what forms do we find mercury in the environment what is special about methyl mercury what conditions are typically necessary to create methyl mercury set 5 concentrations what is the recommended maximum amount of mercury in drinking water nokomis pond the drinking water supply for newport covers approximately 119 acres which is about 805400 square meters it is a fairly shallow pond 10 feet deep or less in most places with a few places where it is about 20 feet deep assume an average depth of 35 meters almost certainly an over estimate a typical mercury thermometer of the kind that used to be common in high school laboratories contains about 3 grams of mercury if you broke one of these thermometers in nokomis pond what would the mercury concentration of the water be would this be something to worry about set 6 scale the measurements we make with mercury are often in parts per billion to make sense out of that we need some physical notion of how big a billion is or putting it in terms of parts per billion if we have something that is say 11 parts per billion we need a way to understand how big a group those 11 items are a part of suppose we had a billion ping pong balls would they all fit in a boxcar if not how many boxcars would it take to hold them here is the basic information you need to figure this out for yourself the diameter of a ping pong ball is 40 mm the volume inside a typical 50 foot boxcar is 14832 m3 because ping pong balls are round there is unused space when you pack them together a good estimate of the usable space when you are packing round things together is 74  reflection formative assessment ideas for a quick check of understanding ask the students to suppose that they found an old style mercury fever thermometer in a medicine cabinet at home and that it broke leaving a little silver ball of mercury on the floor ask them to answer the following questions what would probably happen if the dog ate the little ball of mercury what if the dog just sniffed it what would be a good way to clean up the mercury would it be a good idea to vacuum it up to get all the little pieces students could present their answers to the class check in with students to make sure that they have the correct information before presenting to the class  extension ideas have the perfect extension for an activity like this share it with us in the comments section below teacher s cheat sheet these documents can be viewed by clicking the links below individual pdfs are also on the lesson resources page answer key math warmup answer key question sets answer key reflection formative assessment handouts these documents can be downloaded by clicking the links below individual pdfs are also on the lesson resources page math warmup question sets resources a useful sheet that talks about the meaning of ppm ppb mg kg and so on is available from the center for hazardous substance research  why care about mercury why care about mercury background information introduction mercury the environment essential activity why care   mercury in watersheds background classroom activity  