1. Some of the substances we detected in water were added.
2. Others were removed.
3. All of these substances are dissolved--we did NOT see them at all in either the water sample from the lake or the water sample from the faucet.
We're putting these ideas out there in developing our initial models. We're seeing if we can develop a model that PREDICTS, based on scientific knowledge we've developed over time.
Check out some of the 5th grade initial models of what happens at the purification plant! We have some competing ideas on how dissolved substances are added: microbes, chemicals, filters, screens, earth materials, machines, people...
We can't wait to figure this out!