Like most concepts in chemistry, intermolecular forces takes a bit of imagination and critical thinking to fully comprehend and apply when explaining a variety of situations. Though demonstrating the presence of these forces in a simple and explicit manner can easily be done, I wanted to change how I introduced IMFs a bit this year by focusing on a more data-to-concepts approach.
HS-PS1 Matter and Its Interactions
The solution to Chemical Mystery #15: The Leaky Cup is shown here.
How many of you could recite, word for word, a definition you learned in school? When you first memorized the definition, you could state “inertia is a property of matter”, or “density is mass over volume.” However, you struggled to apply it to a new situation and maybe you were unsure of how to construct a model of what it meant.
Did you know there is a simple test you can do to see if an alkaline battery is fresh or dead? All you need to do is bounce the bottom of a battery onto a hard, flat surface. Guess what causes this difference in bouncing ability between fresh and dead batteries? Chemistry, of course!
The June, 2018 issue of the Journal of Chemical Education contains an article that describes a simple, yet fascinating experiment that you and your students are going to love! It involves the use of butterfly wings from the genus Morpho. I obtained some of these wings and enjoyed experimenting with them. You will too!
It can be difficult to engage students in reviewing for semester exams by using worksheets or practicing problems on the whiteboard. If you are looking to change up your review plans, you might consider using a lab activity that provides opportunity to revisit many of the topics that need to be covered.
I have used several different versions of the Silver Mirror or Tollen's Test lab. I am sharing the method that has proven to be the most reliable for me. The solutions should be made fresh, the directions must be followed closely and timing is very important. I like the fact that relatively small amounts of the chemicals are required, but as always you must be vigilant with safety precautions.
This is a Chemical Reactions lab that I modified to meet NGSS guidelines.
Given the amount of one reactant, students must use stoichiometry to find the ideal amount of the second reagent to use to create purple fireworks. The teacher ignites each groups' fireworks. Ideal mixture create little or no ash. Student assignment sheet with directions (and different initial amounts) plus teacher information and sample answers are included. This is an exciting and engaging activity that can be used as a stoichiometry quiz.
Students will proceed through a pre-lab engagement activity, organize element cards based on similarities & trends, discuss trends with the class and then produce a periodic table that includes the trends discussed within the lab.