<h2>
	<a name="TOC-OVERVIEW"></a></h2>
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	<h2>
		<a href="https://sites.google.com/site/mercuryourwatershedfriends/watershed-experiences/unit-3/research-question-hypothesis/Cartoon_hypothesis.jpg?attredirects=0" imageanchor="1"><img border="0" height="200" src="https://sites.google.com/site/mercuryourwatershedfriends/_/rsrc/1289935445418/watershed-experiences/unit-3/research-question-hypothesis/Cartoon_hypothesis.jpg?height=200&amp;width=200" width="200" /></a></h2>
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<p>
	OVERVIEW</p>
<p>
	&nbsp;</p>
<p>
	This activity is primarily a brainstorming activity that looks at the assumptions, mechanisms, and unanswered questions that are buried in the students&rsquo; picture of the system they are studying. Ultimately, each group will come up with one or more questions and will choose one to turn it into a hypothesis.<span>&nbsp; </span>They will then propose a general approach for a research project that addresses their hypothesis.</p>
<p>
	&nbsp;</p>
<p>
	&nbsp;</p>
<h2>
	<a name="TOC-GETTING-READY"></a>GETTING READY</h2>
<h3 style="margin-left: 40px;">
	<a name="TOC-Materials"></a>Materials</h3>
<ul style="margin-left: 40px;">
	<li>
		Student background materials from Units 1 &amp; 2</li>
	<li>
		Student mercury cycle diagrams, completed in <a href="https://sites.google.com/site/mercuryourwatershedfriends/watershed-experiences/unit-2-1/where-is-hg-how-does-it-move">Unit 2 - Activity B</a></li>
	<li>
		Student <a href="https://sites.google.com/site/mercuryourwatershedfriends/watershed-experiences/unit-3/research-question-hypothesis/3_A_brainstormingworksheet.pdf?attredirects=0">Brainstorming Worksheet</a> (PDF)</li>
	<li>
		<a href="https://sites.google.com/site/mercuryourwatershedfriends/watershed-experiences/unit-3/research-question-hypothesis/3_A_teachersguide.pdf?attredirects=0">Teacher&#39;s Guide</a> (PDF)</li>
</ul>
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	<h3 style="margin-left: 40px;">
		<a name="TOC-Time-Needed"></a>Time Needed</h3>
</div>
<div>
	<h2>
		<a name="TOC-ACTIVITY-PROCEDURE"></a>ACTIVITY PROCEDURE</h2>
	<p>
		&nbsp;</p>
	<h3>
		<a name="TOC-Getting-Ready:"></a>Getting Ready:</h3>
	<p>
		Divide students into working groups. Provide each group with the background materials that they encountered in the preceding units and the mercury cycle diagrams that they produced at the end of Unit 2.<span>&nbsp; </span>The mercury cycle diagrams are the students&rsquo; models of the system that they are studying, and therefore the starting point for their thinking about how they think the system works.</p>
	<p>
		Teachers - take a look at the &quot;<a href="https://sites.google.com/site/mercuryourwatershedfriends/watershed-experiences/unit-3/research-question-hypothesis/3_A_teachersguide.pdf?attredirects=0">Teacher&#39;s Guide</a>,&quot; it may aid you in helping the students brainstorm.</p>
	<h3>
		<a name="TOC-Getting-the-Analysis-Started:"></a>Getting the Analysis Started:</h3>
	<p>
		Typically, you will want to start this by having the students review their diagrams of the mercury cycle, thinking through all of the elements of the system and making sure that they have answers to questions such as:</p>
	<ul>
		<li>
			Where is the mercury coming from and how does it move into the system under study?</li>
		<li>
			Where does the mercury change into its organic, methyl form?</li>
		<li>
			What life is at the bottom of the food chain that takes in the methylmercury?</li>
		<li>
			How does the mercury move up the food chain?</li>
		<li>
			Are there any special features in the actual system under study that might make this cycle more complicated or somehow different than a &ldquo;typical&rdquo; system?</li>
		<li>
			What assumptions are we making at each step of this cycle?</li>
	</ul>
	<p>
		You will almost certainly want to spend some time with each group going over questions such as these, making sure that the students have a workable model and a model that they understand.</p>
	<p>
		Once you are comfortable that a group has a model of what they think is happening, you can start guiding them toward some testable hypotheses.<span>&nbsp; </span>Since the key &ldquo;result&rdquo; or &ldquo;dependent variable&rdquo; that the students will be measuring is the amount of mercury in organisms, you should ask the students to use their model to predict:</p>
	<ol>
		<li>
			Which organisms in the system will have more and less mercury?</li>
		<li>
			What it is about the organisms that might cause them to have more mercury than others? (such as, does their size matter? age? etc.)</li>
	</ol>
	<h3>
		<a name="TOC-Thinking-Ahead:"></a>Thinking Ahead:</h3>
	<h4>
		<a name="TOC-What-kinds-of-data-can-the-students"></a><u>What kinds of data can the students collect?</u></h4>
	<p>
		&nbsp;</p>
	<p style="margin-left: 40px;">
		What the students can measure depends on the types of resources that are available.<span>&nbsp; </span>You should provide them with a list of the kinds of things that they can collect and measure in the system that you are studying.<span>&nbsp; </span>What follows is a partial, very general list.<span>&nbsp; </span><u>The actual list for your site and situation might have fewer elements, or might be larger</u>.</p>
	<ul style="margin-left: 40px;">
		<li>
			Invertebrates</li>
		<li>
			Plants</li>
		<li>
			Soil</li>
		<li>
			Leaf litter</li>
		<li>
			Fish</li>
		<li>
			Human hair</li>
	</ul>
	<p style="margin-left: 40px;">
		In addition to the list of materials and organisms that they might sample, the students need to know what measurements they can make.<span>&nbsp; </span>Again, <u>this list will vary from school to school and site to site</u>.<span>&nbsp; </span>If you have special needs, we can sometimes help you get access to equipment to make additional measurements.</p>
	<ul style="margin-left: 40px;">
		<li>
			Mass or weight</li>
		<li>
			Size (length, other measures)</li>
		<li>
			Number of things collected</li>
		<li>
			Species, or family for dragonfly larvae, or type (e.g., floating versus submerged plants; small mouth bass versus sunfish)</li>
		<li>
			Age<span>&nbsp; </span>(for fish, using analysis of fish scales)</li>
		<li>
			Stomach contents</li>
		<li>
			Gender</li>
		<li>
			Site characteristics&mdash;substrate i.e. muddy or cobble bottom, stream or lake size, type of forest or land cover around the site, stream flow, etc.</li>
		<li>
			Water quality characteristics (such as turbidity, dissolved oxygen, temperature, acidity)</li>
		<li>
			And, of course, mercury in the substance/organism</li>
	</ul>
	<h4>
		<a name="TOC-What-kinds-of-questions-can-the-stu"></a><u>What kinds of questions can the students explore?</u></h4>
	<p>
		&nbsp;</p>
	<p style="margin-left: 40px;">
		For most students you will need to guide them from having a general area of interest toward having a question that can be answered with data.<span>&nbsp; </span>Keep in mind that the students will be able to explore <i><b>two general kinds of questions</b></i>:</p>
	<ul style="margin-left: 40px;">
		<li>
			<b>Questions about differences:</b><span>&nbsp;&nbsp; </span>Does one set of samples contain, on average, more mercury than some other set?<span>&nbsp; </span>There are many questions of this kind.<span>&nbsp; </span>Do people that eat a lot of fish have more mercury in their hair than people who eat beef, but not very much fish?<span>&nbsp; </span>Do bass have more mercury than crayfish?<span>&nbsp; </span>Do dragonfly larvae in a wetland have more mercury than those in a rocky no-wetland site? These kinds of questions will involve a comparison of means, or averages.</li>
		<li>
			<b>Questions about the strength of relationships:</b><span>&nbsp; </span>What goes with what?<span>&nbsp; </span>Is there a strong relationship between the weight of a fish of some species and its mercury burden?<span>&nbsp; </span>Do larger dragonfly larvae have more mercury than smaller individuals? Is there a strong relationship between a fish&rsquo;s age and its mercury burden?<span>&nbsp; </span>Is the size of a person related to the amount of mercury in the person&rsquo;s hair?<span>&nbsp; </span>This kind of question involves creating a scatter plot to see if there is an orderly relationship between the two factors.<span>&nbsp; </span>Of course, it requires that each factor be something that can be expressed in a numeric relationship on the scale of the axis of a graph.<span>&nbsp; </span>So, weight, length, age, and other &ldquo;countable&rdquo; factors work well for this.<span>&nbsp; </span>Something that does not fit into an <a href="http://people.math.sfu.ca/~cschwarz/Stat-301/Handouts/node5.html" rel="nofollow" target="_blank">interval scale or ratio scale</a> won&rsquo;t work.<span>&nbsp; </span>So, you can&rsquo;t do this kind of analysis when the factors on one axis are, say, different kinds of insects (beetles, moths, dragonflies, mosquitoes).<span>&nbsp; </span>But it WOULD work if you were comparing mercury content for beetles of different average weights.</li>
	</ul>
	<p style="margin-left: 40px;">
		Helping the students be clear about which kind of question they are asking will be very useful as you help them think through the design of their experiment.</p>
	<p style="margin-left: 40px;">
		Our experience has been that questions about <i><b>relationships </b></i>often open up richer opportunities for learning than simple questions about differences.<span>&nbsp; </span>Looking at how much two factors are correlated is a good way to get a better understanding of what is happening in a system.<span>&nbsp; </span>Questions about differences are useful too, of course, and provide important insights into the structure of a system.<span>&nbsp; </span>But, if students are looking at an issue that can be explored through a scatter plot, encourage them to pursue that direction.</p>
	<p style="margin-left: 40px;">
		Kevin Simon, Assistant Professor of Biological Sciences at UMaine, gave some feedback on a class&rsquo; hypotheses last year and his comments might help you in the development of your students&rsquo; hypotheses:<span>&nbsp; </span>A hypothesis that <b>explains </b>something leads to more interesting and informative research. Hypotheses that use the words &ldquo;because&rdquo; or &ldquo;due to&rdquo; or &ldquo;cause&rdquo; are generally more informative. See the examples below:</p>
	<p style="margin-left: 80px;">
		<b>Hypothesis #1&mdash;There will be fewer invertebrates in streams subject to frequent floods than in streams that experience less frequent flooding.</b><span>&nbsp; </span></p>
	<p style="margin-left: 40px;">
		You might sample and, indeed, prove that this is so. However, you don&rsquo;t know WHY.</p>
	<p style="margin-left: 80px;">
		<b>Hypothesis #2&mdash;There will be fewer invertebrates in streams subject to frequent floods BECAUSE the stream is highly disturbed, causing high insect mortality.</b></p>
	<div style="margin-left: 40px;">
		This 2nd hypothesis now explains something and it leads to specific predictions that you can test.&nbsp;</div>
</div>
<div>
	<h3>
		<a name="TOC-Right-Wrong:"></a>Right &amp; Wrong:</h3>
	<p>
		&nbsp;</p>
	<p>
		Once each group has identified a question - for example, &quot;Do fish that eat other fish have more mercury than fish that eat algae?&quot; - have students turn the question into a hypothesis by expressing it as an assertion.<span>&nbsp; </span>That means choosing one outcome over the other, based on what the model suggests.<span>&nbsp; </span></p>
	<p>
		It is important to assure the students that a hypothesis is just an educated guess&mdash;a prediction from the model&mdash;and that there is no right or wrong.<span>&nbsp; </span>Scientists don&#39;t use the word &quot;wrong&quot; (or &quot;right&quot;, for that matter) when discussing hypotheses. They will usually say their findings either did or did not support their hypothesis. For example, in the question about fish with different diets, a working hypothesis might be something like, &quot;Because mercury bioaccumulates in food chains, fish that eat other fish will have more mercury in their bodies than fish that eat algae&quot;.</p>
	<p>
		&nbsp;</p>
	<h3>
		<a name="TOC-Mind-onto-Paper"></a>Mind onto Paper</h3>
	<p>
		Students should have some ideas in their heads now.&nbsp; Have them complete the <a href="https://sites.google.com/site/mercuryourwatershedfriends/watershed-experiences/unit-3/research-question-hypothesis/3_A_brainstormingworksheet.pdf?attredirects=0">brainstorming worksheet</a>, which will help them get their ideas onto paper.</p>
	<p>
		FYI - The teacher&#39;s guide includes some guiding advice concerning the brainstorming worksheet.</p>
	<h3>
		<a name="TOC-Study-Design"></a>Study Design</h3>
	<p>
		&nbsp;</p>
	<p>
		Finally, have students brainstorm about how they might do a field research project to address their hypothesis. In our example it might be &quot;catch some of each type of fish and measure mercury in them&quot;.</p>
	<p>
		At the end of the discussion have a student record (on the blackboard and/or web site) the samples that will need to be collected to address the hypotheses. As the research coordinator, determine where some sample collections could be combined. Each class can have a maximum of 20 samples analyzed for mercury for projects focusing on aquatic invertebrates. <b><span style="color: rgb(99, 36, 35);">At least ten samples should be individual dragonfly larvae (you are adding to a regional database for dragonfly mercury).</span></b></p>
	<h2>
		<a name="TOC-EXTENSION-IDEAS"></a>EXTENSION IDEAS</h2>
	<p style="margin-bottom: 0.25in;">
		Have student groups briefly present their questions and hypotheses to the rest of the class.<span>&nbsp; </span>Make sure that they explain the thinking behind the hypothesis.</p>
	<p>
		&nbsp;</p>
	<h2>
		<a name="TOC-DOCUMENTS"></a>DOCUMENTS</h2>
	<p>
		These documents can be viewed by clicking the links below.&nbsp; Individual PDFs of each document can be downloaded from the &quot;Attachments&quot; at the bottom of this web page.</p>
	<h3>
		<a name="TOC-Teacher-s-Guide"></a>Teacher&#39;s Guide</h3>
	<p>
		&nbsp;</p>
	<ul>
		<li>
			<a href="https://docs.google.com/viewer?a=v&amp;pid=sites&amp;srcid=ZGVmYXVsdGRvbWFpbnxtZXJjdXJ5b3Vyd2F0ZXJzaGVkZnJpZW5kc3xneDozOTg0ODk4N2Q0M2M5ZTJk" target="_blank">Teacher&#39;s Guide</a></li>
	</ul>
	<h3>
		<a name="TOC-Handouts"></a>Handouts</h3>
	<ul>
		<li>
			<a href="https://docs.google.com/viewer?a=v&amp;pid=sites&amp;srcid=ZGVmYXVsdGRvbWFpbnxtZXJjdXJ5b3Vyd2F0ZXJzaGVkZnJpZW5kc3xneDozNzVlMTQwNjUxOTJiMzk4" target="_blank">Student Brainstorming Worksheet</a></li>
	</ul>
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