Sustainability Lesson 2:
<< This lesson focuses on waste. It can be observed frequently in developing countries that toxic waste, like batteries are treated carelessly.
This topic requires you to teach some basic ecology first. You can start off with something like 'Plant grows in the soil, cow eats the plant, human eats the cow / drinks the milk, waste goes back to the soil.' Itís very helpful if you have a drawing board and can draw this cycle for the children.
You can also use different cycles, like plant-insects-fish-human. Itís important to make clear that some parts of material are always recycled in the system.
The next step is to add some arrows into the system, for example, 'Toxic waste into the soil.'
Then you follow the toxic waste up the chain until it reaches our body.
Depending on the age and understanding of your kids, you could even add some numbers; a lot of toxic waste goes into the soil =>1 kg of grass has 1 g of toxic waste, Cow eats 1000 kg of grass, but only gives 100 kg of milk => 1 kg of milk contains 10 g of toxic waste. Human drinks 100 liters of milk but only weighs 50 kg => human contains 20g toxic waste / kg. The use of numbers demonstrates how toxins accumulate in the food chain.
If there is heavy use of pesticides in local farming, this is a very important topic to include. Try to make it very clear that whatever substance is put onto the field, it will be found on the humans plate later on.
Use an example that the kids actually have in their daily diet. If they eat only vegetables, you might want to leave out the cow / fish.
To show how toxic their waste actually is you can do a nice experiment:
Grow two plants of the same kind in pots.
Put a slightly damaged battery into one of the pots and let the kids observe over some weeks how it affects the growth of the plant. Make sure that the plants have all the nutrients and enough light / sun so that your ďhealthyĒ plant actually grows well.