Chemical Reactions

While teaching third grade in South America, one of the issues that came up every year was the sticky subject of identifying chemical reactions versus physical ones. I decided to make this point my topic of study when out exploring Internet sites.
I was able to find a number of sites which explained things using big words and a few pictures. I was also able to find a number of sites which gave some great lists of science experiments that can be done but there were two sites that stood out as best facilitating a young child's understanding of chemical reactions. These sites were Andrew Radar's Studio and BBC's Bitesize. What I really loved about BBC's Bitesize is that there is plenty of humor and fun illustrations to keep children entertained. They are reacting and causing things to occur by clinking their mouse, or sliding an image on the page. In this way, they are engaged in the process in more than a mental way. Another thing that I loved is the tests at the end of the lesson which give the students something to measure how much they understood what they saw.
One way that I can tie these sites into a lesson is through using two examples. Students can pour two materials together, such as sand and salt and then try to take them apart. We can discuss how even if the materials were sugar and salt and really hard to take apart, it is still physical if we can. It would take a long time, but we can take them apart. Then we (I) could do a chemical reaction such as burning a piece of paper and allow the students to see how we can not every change that back to being paper again. We could also then discuss how when heat is involved, it is often a chemical reaction which is occurring. Students could take aluminum/metal and put it in a solution which will cause rusting as well. The website's interactive offerings fit well with explaining these experiences.

The students would need to view the site after we mix the salt and sand and before we would work with chemical reactions. This would be a challenge if I do not have computer/Internet access for all my students during that time. The use of a computer lab in the middle of a science lesson would be tricky, but attainable, I believe.

References:
Andrew Rader’s Studio. (1997-2009). Retrieved on June 11, 2010 from: http://www.chem4kids.com/files/react_intro.html; http://www.chem4kids.com/files/react_thermo.html
BBC. Bitesize. Retrieve on June 11, 2010 from: http://www.bbc.co.uk/schools/ks3bitesize/science/chemical_material_behaviour/;