On Tuesday, Manuel Asali, came in to talk to students about chemistry, energy and sustainability. Manuel is a Chemical Engineer and explained to students about how plastics are made and the different types. Manuel's aim was: "to awaken the consciousness that we cannot take our energy sources for granted and to show the application of chemistry in a fun way."
We discussed whether paper or plastic bags are more sustainable based on issues of whether they are reused or recycled, how much water and energy they take to make and how long they take to biodegrade. The answer is not as simple as you think and there are ongoing experiments to improve plastics especially in their biodegradability.
There were lots of practical demonstrations, including showing us how Coca Cola bottles are made. They actually melt down small plastic pellets to make a preform which looks like a test tube. These 'test tubes' are then bought by the companies e.g. Coca Cola and melted again and blown to make their own plastic bottles.
We were also given a practical demonstration of the use of one type of plastic which absorbs water and is used in meat and fruit packaging and nappies to absorb moisture. As one Grade 7 student said: "I liked his examples because they helped to develop his ideas. I liked his example of the diaper powder in the glass to show how they absorb liquid."