Posts

Showing posts from January, 2015

Drawing on the Gas Laws

Image
I recently wrote about a quiz question that asked students to solve limiting reactant problem that depended on a picture , including they needed to draw their solution.  Most of my students had mastered the math and sailed through the calculation part of my quiz but then struggled with the drawing task.  We have moved on now to gas laws, so, when it was again quiz time, I included another drawing item.  This time used a box of dots to represent the particles in a sample of gas.  I asked students to draw me a picture that would represent the particles in a sample with twice as much pressure.  I was checking to see if they understood the model and also if they understood the relationship between gas pressure and the other properties of volume, temperature and number of particles.   Here are some sample student responses: These two are essentially the same, but I like them both for different reasons.  The first with its solid demonstration ...

The Great Squid Challenge

Image
One of the things I love about gas laws is the possibility for inquiry labs .  I start with the conceptual understanding of the relationships between gas pressure, volume, temperature and number of gas particles.  Kids can usually predict the relationships between any two of these four properties; I use this PheT simulation to help them see these relationships after they make predictions.  Then we are ready for a lab. Students bring a plastic bottle to class on the day of lab.  I save bottles at my house and dig through the school trash and recycling bins for kids who forget.   The Great Squid Challenge has two parts.  First students must use a kit to create a working cartesian diver.  I show them a sample, but give them no extra instructions.  I tell them that instead I will give them the pleasure of figuring it out.  Once everyone in the lab group has a working squid, they have a slightly harder task.  Given a bottle and 5 numbe...