The objective of this science fair project is to investigate the effect of hot and freezing conditions on the survival of bacteria. The experiment will be carried out by placing E Coli, Streptococcus and Bacillus bacteria at -78 degrees Celsius, 0 degrees Celsius, 25 degrees Celsius, 60 degrees Celsius and 100 degrees Celsius
Bacteria will be deactivated and destroyed at temperatures above 60 degrees Celsius.
Bacteria are small single-celled microorganisms that measure only a few micrometers in size and exist in various shapes such as spheres, rods and spiral. They can be found almost everywhere around us, even inside our body. . Some bacteria have also adapted, through mutation and evolution, to environments that are considered inhospitable for most living organisms, such as the earth’s crust, acidic water from hot springs and even radioactive waste.
Although most bacteria around us are harmless, some bacteria, which are known as pathogens, can spread diseases and cause people to become ill. It is therefore important to maintain our personal hygiene and to maintain a safe environment by cleaning our homes with disinfectants. However, there are also friendly bacteria which are essential for our survival, such as those that live in our stomach and intestines. These bacteria are useful in helping us digest our food.
Bacterial growth is governed by factors such as temperature, pH, salt concentration, nutrient and oxygen. The optimum temperature for most bacteria to survive and grow ranges from 25 degrees Celsius to 40 degrees Celsius, and the optimum pH ranges from 6 to 8. However, some bacteria, such as psychrophiles and thermophiles, are able to survive and reproduce under more extreme temperatures, at 0 degrees Celsius and 91 degrees Celsius respectively.