Happy New Year! Did you know that 2015 is the International Year of Light (IYL)? IYL is a “global initiative adopted by the United Nations to raise awareness of how optical technologies promote sustainable development and provide solutions to worldwide challenges in energy, education, agriculture, communications and health1”. IYL is sponsored by several organizations with interests in science and science education, including the European Physical Society, the Institute of Physics, the American Physical Society, and the American Institute of Physics. You can find several lesson plans, videos and other educational resources on the IYL website2.
high school chemistry
In a recent post, I indicated that I would make available the Chemical Reactions lab that I modified to meet NGSS guidelines. Enjoy!
2 53-minute class periods (about 2/3 of each class were used).
Happy December ChemEdX community! On December 2, 2014 I attended the second of three workshops on NGSS (Next Generation Science Standards) through our local ISD (in Kalamazoo County it is known as KRESA).
Cellulose nitrate (also known as nitrocellulose or guncotton) is a very flammable substance that is formed by reacting cellulose (also known as dietary fiber) with a mixture of concentrated nitric and sulfuric acids:
Whenever a serious incident takes place in a school chemistry laboratory or classroom, fire and safety officers often pontificate on the incident by quoting the Materials Safety Data Sheet (MSDS). However, how many of you have read such documents in full? In UK schools we have perhaps 200 to 400 chemicals on the shelves. Have you read the MSDSs for each chemical?
In a recent contribution to ChemEd X "Stoichiometry is Easy", the author states that he has "vacillated over the years between using an algorithmic method, and an inquiry-based approach to teaching stoichiometry. " I would like to suggest that there is another approach to mastering stoichiometry and that it should precede the algorithmic one: it is the conceptual approach based on a particle model to represent the species involved in chemical reactions.
This worksheet is intended to be used as a "Guided Instructional Activity" (GIA). Students read a statement that gives a either a conversion factor or a pair of related measures and then write the information as two equivalent fractions ("conversion factors") and as an equality. In each representation, students are directed to give the numeral of the measure, unit, and identity of the chemical.
35 to 45 minutes.
This set of three worksheets are intended to be used as collaborative "Guided Instructional Activities" (GIAs). Two students cooperate to complete the steps of a stoichiometry problem, alternately doing parts of the process as they explain what they are doing and evaluate their partner's work. These worksheets emphasize an algorothmic approach that helps students learn to think aobut the purpose of a question, organize their work, set it up so that it is easily readable and can be followed by others, and make good use of "unit analysis" (dimensional analysis).
Each of the activity worksheets requires 40 to 55 minutes.
The three "Guided Instructional Activities" in this activity are three cooperative learning pieces in which students are guided through the process of converting from one unit to moles (or moles to a unit) by the method of "unit analysis" (dimensional analysis). Students alternate steps in the process and evaluate the success of each step. They must do things such as writing the given information correctly, finding the correct molar mass, setting up the mathematics correctly, and determining the answer to a required number of significant figures.
Each of the activities requires about 40 to 55 minutes. The first one used usually takes longer, the last goes quicker.
This worksheet asks students to do basic conversions of mass or molecules to moles and vice versa. The worksheet requires students to complete their work in a particular format and to inlcude number, unit, and chemical identity for each item in the "given," in each conversion factor, and in the answer. It gives students basic practice in this mathematical exercise while inforcing good habits that encourage "unit analysis" (or dimensional analysis).
This worksheet can be used as an in-class or as a homework assignment. The ten items on the first page should take 20 to 30 minutes. The ten items on the second page should take 30 to 50 minutes.