Practicums in Chemistry

forensics practicum

If you are familiar with Modeling Instruction in physics, you know there are awesome assessments at the end of units called practicums. First, let me distinguish between practicals and practicums. The purpose of a lab practical typically is to assess a student’s ability to collect and analyze data. These assessments tend to be more technique-based than problem solving-based. The purpose of a lab practicum is to assess a student’s understanding of the content by completing a hands-on challenge. These assessments focus more on problem-solving skills than technique.

In one of my favorite physics practicums, students are asked to observe 2 battery buggies moving at different speeds in opposite directions and they must determine at what point the buggies will collide. This type of assessment is awesome because it is hands-on, there is a tangible right answer and students get to be creative and choose their problem-solving approach to the challenge.

It is a little more difficult to write practicums for chemistry because we foremost have to worry about safety. Beyond that, many concepts in chemistry do not lend themselves to this type of open-ended, hands-on problem solving (at least not with the equipment we have available in high school classrooms). With a little creativity (and some help from fellow Modelers), I have a practicum for every unit of my chemistry course. You will see a quick synopsis of my practicums by unit below. For some of these, I admit the term “practicum” is used loosely but they are all hands-on assessments. My students work in groups to complete these practicums.

Unit 0: Underpinnings: Students must measure the length of the hallway but they are not allowed to take their meter stick past a certain point. Students must create some unit ratio to measure the hallway. Some use floor tiles, some use feet, some use composition notebooks. The tricky part is rounding to the appropriate number of significant figures!

Unit 1: Physical Properties of Matter: Students are given a film canister and some sand and are told they must get the film canister to float with 95% of the canister submerged in the water.

Unit 2: Particles in Motion I: Students observe various demonstrations and must explain how they work at the particle level (egg in a bottle, can crush, marshmallow in syringe, lung model).

Unit 3: Particles in Motion II: Students are given a calorimetry set-up (with copper shot) and are told what the final temperature the water in their calorimeter (styrofoam cup) must be. The only other information students are given is the specific heat of copper.

Unit 4: Describing Substances: Students complete a mixture separation where they must separate salt, sand and iron filings. Separations are judged on percent recovery and relative purity.

Unit 5: Particle with Internal Structure: Students roll a set of dice to determine what elements they will be combining. Students must predict the type of compound that will be formed, give the name, formula and predict properties. This is one where the term “practicum” is used loosely.

Unit 6: Chemical Reactions: Students complete two chemical reactions (one exothermic, one endothermic) and they must predict the products based on observations, write the balanced equation, write the equation in words and draw an LOLOL chart for the reaction.

Unit 7: Counting Particles Too Small to See: Students must experimentally determine how many moles of water are in a given hydrate. Students are given a general procedure to ensure safety but are given no direction for calculations.

Unit 8: Stoichiometry: In the past, I have used Flinn’s micro-mole rockets as a practicum for this unit. Students must figure out they need a 2:1 ratio of hydrogen gas to oxygen gas for the most efficient reaction. I am currently working on a new practicum where students will have to react sodium bicarbonate and acetic acid to get a soap bubble to float at a certain height in a tub.

Unit 9: The Nucleus: I just got a grant from the American Chemical Society to purchase radiation monitors and shielding materials. This year I will be giving students a household item that is radioactive (a Fiestware plate if I can get my hands on one) and students will be evaluating the relative hazard of the material based on the type of radiation it is emitting. Previously, this unit did not have a practicum, just a set of context-rich problems and a writing assignment.

Unit 10: Beyond the Nucleus: Last year I came up with a murder mystery forensics activity on a whim because students were getting burned out during state testing week. This year I’m making it into a practicum. This practicum covers Unit 10 concepts as well as Unit 9 and Unit 7 concepts. Students must determine what tests they want to run at a crime scene and they either get to do an experiment or they get to analyze data. Topics include chromatography, miscibility, empirical formulas and average atomic mass from mass spectrometry data. At the end, students write an expert witness testimony to help convict the murderer.

Hopefully these assessments give you some creative ideas! What hands-on, problem-solving assessments do you use in your class?

 

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Comments 2

Bob Worley's picture
Bob Worley | Sun, 10/02/2016 - 01:07

Lauren

Setting up challenges like this was called Great Egg Racing after a BBC televion show on air from 1979 to 1986. The Royal Society of Chemistry presented some chemical versions and they are still around. You might find some ideas.

http://www.rsc.org/learn-chemistry/resource/listing?searchtext=In+Search...

I used them in little "Olympiad" competitions we developed at that time. They dropped out of favour as the syllabus became more prescripted.

I am becoming rather concerned at all your safety worries in the States. I know there have been demonstrations that have caused serious burns (poor procedure to blame) but has something else happened such as poisoning or chemical burns during student activities? Safety has to be addressed but it should not prevent challanging practical work and working on sklls. It has been (and still is for 2 days a week) my main job to ensure safety in UK chemistry activitites at CLEAPSS (www.cleapss.org.uk) and fuelled my interest in microscale  chemistry www.microchemuk.weebly.com.

Lauren Stewart's picture
Lauren Stewart | Mon, 10/03/2016 - 10:02

Hi Bob,

Thanks for the links! I will be definitely be using some "chemical egg races" in my classes! As far as safety goes, my main concern is giving students procedures or precautions to follow when needed. If a practicum is going to involve the highest level of problem solving, I don't want to give students much in the way of directions. For some challenges (like my calorimetry or hydrate practicums) where students are working with chemicals and Bunsen burners, I would be doing my students a disservice if I didn't give them (or help them come up with) a safe procedure and then leave the mathematical problem solving to them. I just try to find the right balance between letting students come up with the own procedure and safety. I find that the money and equipment issue is far more limiting than the safety issue. 

Lauren