# Yeast Lab Report

```Growth of yeast in different drink lab
By:Edward, Nick
A. Purpose and Hypothesis
The effect of different liquid on the amount of carbon dioxide produced by the
yeast and the growth of the yeast.
What factor are you looking at that you think might affect the amount of
carbon dioxide produced?
The sugar in the liquid and maybe the ph and the other materials in the liquid.
Briefly describe how you will carry out the experiment?
We will set up different test tubes containing different
liquids(Coke,Redbull, Fruit juice, chocolate milk and Green Tea), and add yeast in
the test tubes, then see which kind of liquid produces the most Carbon Dioxide and
which helps the growth.
What is your hypothesis (prediction)? What do you think will happen?
I think that the Redbull and the fruit juice will help the growth of the yeast and
coke will produce the most Carbon dioxide.
Why you think this will happen? (use your knowledge of yeast and cell
respiration) Quote sources if you use them
I think Redbull and fruit juice will help the growth of the yeast because they both
contains a lot of sugar, and the Redbull has a lot of other things that contains
energy.I think the coke will produce the most carbon dioxide because it already
has a lot of Carbon dioxide in it.
B. Variables
Input /Independent variable – the factor you will test and change
Output /Dependent variable – the factor you will measure
Control variables – the factors you will keep the same
1. Input / Independent variable:
I will change the liquid in each test tube by pouring different liquid in different
test tube.
2. Output / Dependent variable:
I will measure the growth of the yeast by looking at the test tube and measure
how much did it grow.
I will look at the amount of Carbon Dioxide produced by placing a ballon on top of
the test tube and see the size of the ballon being blown up.
3. Control variable #1:
I will keep the temperature of the liquid controlled by keeping the temperature of
the liquid in room temperature.
4. Control variable #2:
I will keep the amount of the yeast the same by measuring before adding it in.
5. Control variable #3:
I will keep the amount of liquid being added to each test tube the same by
Method
List of equipment
•
•
•
•
•
•
•
•
•
15 test tube
3 test tube rack
1 can of Red Bull
1 Chocolate milk
1 bottle of Green Tea
1 bottle of Orange Juice
1 bottle of Coke
1 pip tee
A lot of Yeast solution
Plan
1. Set up the equipments
2. Measure using a 50 ml measuring cylinder and pour 9 ml of 5 kinds of liquid in
5 different test tubes
3. Use the pip tee to suck up and measure 2 ml of yeast solution
4. Put the yeast solution in the test tube
5. Repeat 3,4 for the other 4 test tubes
6. Put balloon on each of the test tubes
7. Set timer for 15 min
8. After 15min,observe the Co2 produced and the growth of the yeast in each
set.and write the data down. Then set timer for another 15 min.
9. After that 15 min, observe and record data again.
10. Repeat step 2,9 for the other 2 sets
11. Write Lab report
Diagram
Draw and label a diagram of what your experiment setup will look like. IN PENCIL.
Use a ruler
Results
Put the units you are measuring in, in the headers only in brackets
Independent
SET ONE
SET TWO
SET THREE
AVERAGE
variable
Growth of
Growth of
Growth of
(mm)
yeast(mm)
yeast(mm)
Yeast(mm)
Chocolate Milk
0
0
0
0
Red Bull
25
7
5
12.33
Green Tea
11
6
17
11.33
Coke
73
42
68
61
Orange Juice
32
18
9
19.66
Set 1
Set 2
Set 3
Growth of yeast in DIfferent Drinks
Length of growth of Yeast
80.00
60.00
40.00
20.00
0
Chocolate Milk
Red Bull
Green Tea
Coke
Orange Juice
Types Of Drinks
Observations:
First Set:
15min:
Yeast Growth= At the first 15 minutes the yeast hasn’t start growing yet.
Balloons=The balloons are all empty as well
Bubbles=The coke has made a lot of bubbles, but the others don’t have any
30min:
Yeast Growth=The yeast did not grow any in the chocolate milk. There were Yeast
growth in the other 4, Coke has the most yeast growth and CO2 produced.
Balloons=The balloon of the coke test tube were pumped up alittle
Bubbles=There isn’t any bubbles in Chocolate milk and the other 4 all have
bubbles, the coke test tube is full of bubbles
Second Set:
15min:
Yeast Growth=A little for orange juice and a tiny little for red bull, others none.
Balloons=Balloons are all flat
Bubbles=Coke test tube has a little bubbles and others have none
30min:
Yeast Growth=There are none for chocolate milk.A little for Red Bull. Medium for
Green tea and Orange juice. Quite a lot for Coke
Balloons=All of the test tubes has a little air in it.
Bubbles=There are no bubbles for chocolate milk. A little for RedBull and Green
tea. Medium amount for Orange Juice and many for coke.
Third Set:
15min:
Yeast Growth= A little for Green Tea, non for others
Balloons= A little air in coke’s balloon, others flat.
Bubbles=None for chocolate milk, a little for Red bull, Green Tea and Orange Juice.
A lot for coke
30min:
Yeast Growth=None for chocolate milk, A little for Red bull, Orange Juice and
Green tea, a lot for coke
Balloons=All has a little air in it, coke and orange juice has the most
Bubbles=None for chocolate milk, a little for Red bull , orange juice and Green tea,
Full of bubbles in coke.
Conclusion:
Looking at the result and the data, my hypothesis is mostly right, coke not just
most.The other two that i guessed that will grow were right too, the red bull
and orange juice all made the yeast grow pretty much. Below, i made a diagram
show the rank of growth in all three sets:
Chocolate
Milk
Red Bull
Green Tea
Coke
OJ
Set 1
5th
3rd
4th
1st
2nd
Set 2
5th
3rd
4th
1st
2nd
Set 3
5th
4th
2nd
1st
3rd
Evaluation:
I think this experiment is pretty successful because as you can see at the
diagram above(the rank one). The results were very similar, set 1 and set 2
even have the exact same rank, so it makes this experiment’s data more
reliable. In this experiment, i think the successful part is the reactions that
happened during the experiment, most drinks produced Co2 and had made the
yeast grow in different amounts. The part that is not that successful is that we
might not controlled the water temperature that well, we put all of them in a
water bath all set the 40 degrees though, but the times were slightly different,
some are 1.5 minutes and some are 1 minutes. If i could improve the
experiment, i will observe more and make the temperature of the water and the
timing more accurate(its pretty accurate now, but we could still make it to
perfect), so that it can maybe make the data more accurate. Overall, this
experiment is pretty successful.
```