Lab: the Effect of Mass of Sugar on the Amount of Carbon Dioxide Generated by Baker S Yeast

Teacher Notes

Lab: The Effect of Mass of Sugar on The Amount of Carbon Dioxide Generated by Baker’s Yeast

ñ  This lab can be done in a life science/biology class or a chemistry class.

ñ  I tried this lab using the “one computer, one camera” classroom challenge.

ñ  I made 5 groups in each of my 4 science classes: control; 0 grams of sugar, .1 gram of sugar, 3 grams of sugar

ñ  I had an Incubator in classroom (can be rented from a local 4-H club) set up at a 80 degrees as a constant temperature source

ñ  Each group measured 15 ml of water into a test tube, added .2 grams of yeast and then, depending on the group a certain amount of sugar. They then put a balloon over the test tube and put it in the incubator for 30 minutes.

ñ  At 30 minutes, each group took their sample out, twisted the balloon on top of the test tube, then put the balloon on another test tube with 5 ml of .04% BTB in it. They then inverted the test tube to expose the BTB to any CO2 that collected in the balloon.

ñ  One by one, each group then came up to the camera station and photographed their sample.

ñ  I did the same experiment in each of my 4 classes, controlling for light, etc. That way, I had 4 trials.

ñ  Using 1 computer and projecting onto the screen (LCD projector), I showed the students color basics and we played the color matching game (which they loved). The readily got the idea that yellow light is made up of red and green light and, depending on the shade of yellow, also some blue light.

ñ  For each class, I then opened up the control image in ADI and showed the students how to use the rectangle tool.

ñ  As a class, the kids decided to try to quantify the “yellowness” of the BTB by adding the number of red and green pixels from the sample rectangle together. Alternatively, we could have recorded the blue pixels in the rectangle.

ñ  The students recorded the sum of red and green pixels for the control, 0 grams, .1 gram, etc. for their class. Later, I shared the data from all classes so that all students had 4 trials at each level of the independent variable.