Does litter that ends up on the ground disappear by itself, or does it hang around for 1 year or maybe 100 years? Use litter collected by the students and/or ask them to bring waste from home, so that you get an assorted collection of everything from glass to plastic, metal, newspapers and fruit peel.
1. Lay out a long rope as a timeline in the classroom, or draw a chalk line in the playground. Mark out several points of time along the line, showing years or centuries.2. Get the students to work together, ideally in pairs or groups. They should place the litter along the timeline according to how long they believe it takes for each item to decompose so that it is no longer visible. 3. Go along the timeline with the class and discuss it. Have they got it right? Work through various points; for instance, how is it that certain items disappear quicker than others? Also talk about, for example, the fact that plastic can cause harm even when it is no longer visible. 4. Discuss what we can do to save the earth’s resources and reduce the quantity of litter by reusing more, recycling and making smarter choices when we shop, etc.