What was the positive control group? Video 1:Today I am going to test if masks really work.I wanted to see if surgical masks and cloth masks can stop the spread of germs.To keep things clean I am going to do my experiment in the hood but I am turning off the blower to make sure a cough can spread properly.(shown: a laminar flow hood--an enclosed work bench designed for sterile technique, it has surfaces that you can clean and it has a built indirectional air flow that keeps the experiment clean by decreasing contamination; turning off the blower means that any air flowing in the hoodwill be due to the experiment)First things first, I spray the hood with 70% ethanol and sterilize. (ethanol is sprayed across the work surface and the benchtop is wiped down)Then I measure out 1 foot. That's the distance I am going to test my cough at. (a measuring tape is used to measure one 'foot'-- 30 cm)Then I coughed at three different plates. One without a mask, one wearing a surgical mask and and again wearing a cloth mask. (series ofquick clips showing a scientist coughing towards an agar plate standing on its side, wearing no mask, a blue surgical mask, and a cloth mask)I also got a pump from the dollar store to simulate a cough and replicate air flow without germs. (video shows a pump used to inflate balloons)I expelled air directly at a plate, through a surgical mask and through a cloth mask. (series of quick clips with the air pump shooting airtowards a plate, same three conditions)And, as always, lincluded a negative control. (holds up a plate)I am going to put these at 37 degrees and we will see what grows. Come back for part 2. (puts a stack of agar plates into an incubator)Video 2:A week ago I started a demonstration to show how well masks work.I measured out a foot and coughed on plates without a mask, using a surgical mask and using a cloth mask. (note in this recap the plates arenow red--the scientist has repeated the first part of the experiment using different growth medium in the plates because the original type ofmedium did not include sufficient nutrients to allow for growth of the types of bacteria that grow in your mouth).I also simulated a cough using an air pump and left the plates for 48 hours.My negative control has no growth. (red agar plate, no growth)Simulated cough also had no growth. (Shown: Simulated cough plates (from air pump) No mask has no growth, surgical mask no growth, clothmask no growth)This means that any microbes that grow likely came from my mouth and not the air being pushed by my cough.When I really coughed only the no mask plate had growth (shown all three plates, no mask plate has 8 colonies)There are 8 colonies on the plate but with such little growth we can't really say much so I repeated the experiment coughing directly onto theplate. (shown: scientist coughing directly onto plate, label is cough at 0 ft)The results are significantly more clear. The only growth is observed when no mask is used. (shown three plates, no mask plate is covered inwhite colonies)

A positive control group in an experiment is a group of people that receives the treatments and is…

Video 1: Today I am going to test if masks really work. I wanted to see if surgical masks and cloth masks can stop the spread of germs. To keep things clean I am going to do my experiment in the hood but I am turning off the blower to make sure a cough can spread properly. (shown: a laminar flow hood--an enclosed work bench designed for sterile technique, it has surfaces that you can clean and it has a built in directional air flow that keeps the experiment clean by decreasing contamination; turning off the blower means that any air flowing in the hooc will be due to the experiment) First things first, I spray the hood with 70% ethanol and sterilize. (ethanol is sprayed across the work surface and the benchtop is wiped down Then I measure out 1 foot. That's the distance I am going to test my cough at. (a measuring tape is used to measure one 'foot'-- 30 cm) Then I coughed at three different plates. One without a mask, one wearing a surgical mask and and again wearing a cloth mask. (series of quick clips showing a scientist coughing towards an agar plate standing on its side, wearing no mask, a blue surgical mask, and a cloth mask) I also got a pump from the dollar store to simulate a cough and replicate air flow without germs. (video shows a pump used to inflate balloons) I expelled air directly at a plate, through a surgical mask and through a cloth mask. (series of quick clips with the air pump shooting air towards a plate, same three conditions) And, as always, I included a negative control. (holds up a plate) I am going to put these at 37 degrees and we will see what grows. Come back for part 2. (puts a stack of agar plates into an incubator) Video 2: A week ago I started a demonstration to show how well masks work. I measured out a foot and coughed on plates without a mask, using a surgical mask and using a cloth mask. (note in this recap the plates are now red--the scientist has repeated the first part of the experiment using different growth medium in the plates because the original type of medium did not include sufficient nutrients to allow for growth of the types of bacteria that grow in your mouth). I also simulated a cough using an air pump and left the plates for 48 hours. My negative control has no growth. (red agar plate, no growth) Simulated cough also had no growth. (Shown: Simulated cough plates (from air pump) No mask has no growth, surgical mask no growth, cloth mask no growth) This means that any microbes that grow likely came from my mouth and not the air being pushed by my cough. When I really coughed only the no mask plate had growth (shown all three plates, no mask plate has 8 colonies) There are 8 colonies on the plate but with such little growth we can't really say much so I repeated the experiment coughing directly onto the plate. (shown: scientist coughing directly onto plate, label is cough at 0 ft) The results are significantly more clear. The only growth is observed when no mask is used. (shown three plates, no mask plate is covered in white colonies)