Science Strategies: Inquiry-Based Instruction

 In another life, I did some consulting, regarding inquiry-based instruction.  Labs should be inquiry-based as often as possible.  Why?  Kids do more thinking with inquiry labs.   For example, you can follow these DNA Extraction Instructions to the letter.  Instead, change a variable.  Change the detergent: soft soap, shampoo, different liquid detergent brands, etc.  or change the temperature of the alcohol; chill it.  Does the change in the variable change the outcome? Does isopropyl of ethanol produce more strands of DNA?  Be sure to change ONE variable to make comparisons. (BTW, the key is to use fresh meat tenderizer.  Usually Dawn dish detergent works best among detergents.)

We do this a lot.  For example, look at Flinn’s Chromatography Challenge.  Vary the brands of felt markers.  Try water, isopropyl alcohol, and ethanol.  Vary the solutions or ratios of water and alcohols.  How does each change in variables change the outcome?  You can do inquiry science with a standard, paper chromatography lab.  Try using plain water and different alcohols, or different concentrations of alcohols with the same brand of black pen.  You might use the same alcohol solution and compare different brands of black pens.  You’re extending the lab.  

Another idea is to modify Photosynthetic Flotation lab; it uses spinach leaves.  This version modifies the sodium bicarbonate solution.  It also suggests trying Swiss Chard or ivy.  If you compare results between spinach leaf disks and Swiss Chard disks, the lab becomes inquiry based.  The same is true if you just make a weak solution of citric acid to use instead of the bicarbonate solution.   

Try to compare rates of reaction with The Alka-Seltzer Reaction.  Instead of using this lab, give the kids the tablets and ask them to think up ways to make the tablets react quickly: break up the tablets, crush vs whole, or change in water temperature.  You give the kids the tablets and let them run with it.  Then make Alka-Seltzer Rockets.  What combination of tablet and temperature works to launch the rocket?  

I try to make density, more inquiry based.  Here is a standard density of metals lab.  We review how to determine density, mass/volume.  I demonstrate how to measure volume by displacement.  The kids use rulers and calipers to measure cubes.  Which method, direct measurement or displacement is more accurate?  (The method with calipers produces results closest to the accepted values, the densities in the lab chart.  The lab also explains percent deviation, also called percent error.)  I give the kids the materials and let them design the lab, ideally with a data table.

Even labs, such as this Activity Series can be more inquiry based.  I set out the materials and ask the kids how we could test to see which metal is more reactive.  If there is a chemical change, there is a chemical reaction.  Sometimes, I show the kids the lab set-up and ask how we can tell which metal is most reactive and which metal is least reactive.  Usually, they see they’ll have to set up test tubes with all kinds of combinations of metals and metallic solutions to run tests.  The more the kids can think up their own lab designs, the better.  Here is a conductivity lab, kids can use to design the experiments.  

Whenever, I see an opportunity to change one variable, omit some instructions, or just make the kids think, I use it.  Ask the question: ‘What if….?’  When I give them tools with limited instructions, I still take an active role.  How are you going to set up your lab?  What are you trying to determine?  How are you organizing your data?  What do you think will happen?  Which variable do you think has the most impact?  Inquiry labs often mean less time setting up labs and more time getting my teens to think.