Week+8

Activity Notes:
Here is a simple write-up for the Fortune Fish activity. Note that brevity is a virtue (teachers don't like to read lengthy instructions any more than students).

Chemical Safety
Chemical safety is an essential aspect of being a science teacher. You are responsible for understanding the properties and safe handling of all chemicals in your classroom and storage areas.Your school should have a safety manual, but it will probably not be all-inclusive for your science lab. One solution is to assemble your own manual with essential information for your classroom/lab.

One of your best tools for safe chemical handling is the MSDS (Material Safety Data Sheet) for each chemical on hand. It contains everything you need to know (and more) about your supplies. It is a legal requirement for you to have an MSDS readily available for each chemical on the premises. A copy is always shipped to you with chemical purchases, but it is easy to download MSDSs from the web. These can be printed and filed alphabetically in a labeled binder or file drawer. MSDS vary somewhat in format, but they always include the same information:



Two of the best web sources for MSDS:

[|Flinn Scientific] (contains most chemicals used in schools) [|Sigma-Aldritch] (one of the largest chemical suppliers for labs)

Here is a copy of the MSDS for a specific hydrochloric acid solution. I recommend glancing through it and noting the information that is available.



Flinn has a particularly clear description of proper chemical labeling:



pH Indicators
pH is a very difficult topic to teach properly; if you don't believe me, check out the Wikipedia entry. If you don't understand most of what's in the article, then you don't understand pH. Too often pH lessons become abstract (for obvious reasons), with students getting the message that pH is just a "thing" that occurs. If you decide to address the topic, it is best to do so in real world applications where you do not need to discuss much theory.

In simplified terms, pH indicators are chemicals that change color when they dissociate into a negatively charged form, usually by releasing a hydrogen ion:

Indicator--H ====> Indicator - + H +

This is a [|good website] for a relatively simple explanation of how indicators work. The "water into wine" trick is fun, but it needs to be placed into a scientific context for students; otherwise it really is just "magic."