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Solubility and Models

Chad Husting | Sun, 11/15/2015 - 19:05

First, I had my students examine the conductivity of a puddle of water the size of a nickel. They checked for conductivity. Then they took a very small amount of sodium carbonate and a fresh puddle of water and pushed in a few crystals from the side.  You can still see the crystals in the water but it tested positive for conductivity. They had to explain this. They did the same with a fresh puddle of water and a few crystals of copper (II) sulfate. Again, it tested positive for conductivity but they could still see the blue crystal. Finally, they started again with another fresh puddle of water, pushed a few crystals of sodium carbonate on one side and on the opposite side they pushed in a few crystals of copper (II) sulfate.  After waiting five minutes, a solid dull blue precipitate formed in the middle.  Also, the drop tested positive for conductivity. 

JCE Pick - Linked Formative Assessment

I used to be big into concept maps as an additional way for my students to show understanding besides a quiz or test. In fact, so much so, that my students a few years ago had to make a concept map as a mandatory test review. I’ve shied away from that over the past few years in a new school (why? I’m actually not so sure) - probably because I got too much information from my students about their level of understanding. I’m sure if I conducted a rigorous method of assessment, there would be a correlation between how well students could connect ideas and assessment scores.

Cookbook to Inquiry....Another Attempt

Chad Husting | Sun, 10/25/2015 - 19:32

There is a hydrate lab which is done by many teachers. Typically, students first use a known hydrate and are provided the formula.  As an example, they might use CuSO4 . 5H2O.  On paper, they would work through the percent by mass of water in copper (II) sulfate pentahydrate.  They then would be given a mass of the copper (II) sulfate pentahydrate, calculate how much water they should lose and then they would heat it and compare the data with the calculated value. Next, they are given an unknown hydrate.  They are also given the molar mass of the unknown salt of the hydrate and they have to calculate the molar ratio of salt to water based on their data.  Here is one possible way to “tweak” this lab.

Going from Cookbook to Inquiry...Messy but worth it.

Chad Husting | Mon, 10/19/2015 - 13:35

We, as teachers, can see that life is sometimes like this and we care enough about our students that we want to try to prepare them for careers and problems that we can’t even imagine….because we believe that good education can empower people to go further and reach higher than they could ever dream….and maybe the journey we will  start together begins with a simple question in which the answer may not seem immediately obvious...and that is O.K….

Veritasium in the Modeling Classroom

Erica Posthuma | Mon, 10/19/2015 - 09:53

Modeling InstructionTM is specifically designed so students construct meaning without being told what to think and I needed videos that aligned with this philosophy.  That’s when I ran across this TedEd talk with Dr. Derek Muller.

Real World Application: Drain Cleaners - Should I use them?

Dan Meyers | Fri, 10/16/2015 - 15:01

Common drain cleaners consist of water, sodium hypochlorite (bleach) and sodium hydroxide (base) and/or potassium hydroxide (base). Bases are caustic (caustic loosely means to gnaw or eat away at) and can cause corrosion in metal pipes. Wouldn’t you know, our house has PVC piping through the fixtures that dump into a 45 year old cast iron pipe. The cast iron pipe is old and currently shows signs of surface rust and corrosion to the point where the pipe appears to be leaking then sealing itself in several spots. Not to mention the interior of the cast iron pipe may not be completely open, thus, not permitting a fast flow in drainage. Good news: a home warranty is being taken advantage of to hopefully replace the cast iron pipe with a PVC pipe.

 

The Gas Laws Are Out of This World!

Tom Kuntzleman | Tue, 10/13/2015 - 13:01

A few years ago, we launched a weather balloon during our summer science camp. The balloon reached an altitude of 30 km (100,000 ft)! Among other things, this project ended up being a great way to teach campers about the gas laws and how atmospheric pressure decreases with altitude. 

Thank you "Lady from Texas"

Chad Husting | Sun, 09/27/2015 - 17:17

At Chem Ed 2015, a teacher from Texas showed me this quick and dirty way to do a distillation that the kids can do. I forgot her name. "Lady from Texas", let me just say "thank you". If you are reading this, please shoot me an email and I will be more than happy to give you credit. It worked really well.

“In the Lab before Christmas” – A Chemical Demonstration and Education Show

David Licata | Sun, 09/20/2015 - 23:46

Most chemical educators will agree that exciting demonstrations are excellent motivators to create interest in science. They are also a way to create interest in the community, motivate the student-demonstrators, and perhaps to make a little money to support special activities of an ACS Chem Club. Chemical demonstration shows, organized around holidays or other special occasions have a long and honored history.  Pacifica High School (Garden Grove, CA) took its inspiration from the lecture-demonstrations of Michael Faraday, given during the Christmas holidays of 1860-61. (The Chemical History of A Candle).