What are some examples of incomplete combustion? 1.Bunsen burner with air hole closed 2.Starting a wood fire or bbq 3.Turning a log-burner down low overnight 4.Engines or boilers that have not been serviced Why is incomplete combustion particularly dangerous? 1.Soot (carbon) makes things dirty 2.Soot can irritate the lungs and cause respiratory disease 3.Smog in Christchurch 4.Carbon monoxide is poisonous because it prevents oxygen binding to haemoglobin in your blood 5.CO is particularly dangerous because it is colourless and odourless (can’t smell it) Do now: Hātarei, 9 Haratua 2015

Learning Objectives Understand that scientists’ investigations are informed by... 1)current scientific theories, and 2)evidence that will be interpreted through logical argument

Do now: Imagine: You come in to the lab and Mr Cooper is nowhere to be seen. All you can see are his shoes and some charred remains. Explain: Use the fire triangle, or other scientific theory, to write down an explanation for his mysterious disappearance

Video clip

Theory 1: Static electricity builds up in or on the body and is ignited by a new subatomic particle called a pyroton, which interacts with human body cells... but no scientific evidence proves the existence of this particle Source:

Theory 2: Methane builds up in the intestines and is ignited by enzymes (proteins in the body that act as catalysts to induce and speed up chemical reactions)... but most victims of spontaneous human combustion suffer greater damage to the outside of their body than to their internal organs, which seems to go against this theory Source:

No one has ever conclusively proven or disproven the truth of spontaneous human combustion......how would you? Most scientists say that there are more likely explanations: many victims were smokers who were later discovered to have died by falling asleep with a lit cigarette... a number of victims were believed to have been under the influence of alcohol... a number of victims suffered from a movement-restricting disease that prevented them from escaping the fire... some of the fires and strange states of the victims' bodies were the result of a criminal act and subsequent cover-up