PLANNING LAB ON SEED GERMINATION
This is a step-by-step work sheet to help you plan your first lab. I have put examples of each step in italics. The topic of this lab
is factors that are related to germination in seeds.
Some very brief information on germination:
A seed is the embryo (fertilized egg) of the plant. Most
plant seeds undergo a period of dormancy so that they
sprout when conditions are optimal for survival.
Depending on what the habitat of the plant is, the seed
may need to be exposed through certain conditions
before it germinates. Some seeds need a period of cold,
some need certain light conditions, others require heat,
extremes of pH or mechanical abrasion.
1.
Identify some variables that could affect seed germination. This is called the INDEPENDENT VARIABLE:
A.
B.
C.
D.
2.
_temperature________________________
___________________________________
___________________________________
___________________________________
How will you know if one of these variables has affected the germination, what are some ways you could measure the
effect? This is called your DEPENDENT VARIABLE:
A. _# of seeds that sprout/day_____________
B. ___________________________________
C. ___________________________________
D. ___________________________________
3.
Choose one IV and one DV. Use these to write your hypothesis about what you think will happen to the seeds because
of the IV, this is your conditional statement. Start by writing the statement I think…..because. The “because” part of
this should relate to some scientific principle. I think that temperature will affect how many seeds sprout because
temperature affects metabolic reactions and living organisms have optimal temperatures for these reactions.
(Miller)
Your prediction:_________________________________________________________
Now write what is called a formal hypothesis in the form If….then….. (Be specific). In order to be useful a hypothesis
must be testable. It should only have 2 variables: the IV and the DV and should say what you think the relationship is
between them. If temperature affects germination rate in mung bean seeds then increasing temperature will
increase the number of seeds that germinate per day up to 40 degrees Celsius.
Your formal hypothesis:________________________________________________________
4.
5.
Now you need to make some more specific plans about your experiment. First of all you have to make sure you are
conducting a Fair Test; in other words are you only testing one variable? To do that you have to control any other
variable that might affect the outcome. So any other variable you had listed in question #1 must stay the same. These
are called your CONTROLLED VARAIBLES. List the variables that need to be controlled in this experiment:
1. ______________________________________________
2. ______________________________________________
3. ______________________________________________
4. ______________________________________________
6.
The next step is determining how many different levels of your IV you will have, sometimes this is just + or -. In this
example, I could have 4 temperatures: 10, 20, 30, 40 degrees Celsius. This is the LEVEL OF THE IV.
Your levels of IV:___________________________________
7.
The next decision is how exactly you are going to measure your DV. In my example I will decide when I will check
my seeds, what I will consider “sprouted” and how many seeds I will have in each level of my IV- this is called
SAMPLE SIZE. Its better to have more than one seed in each level of the IV. I will put 10 seeds in each of my four
levels.
Your meausrement of DV and sample size:
__________________________________________________________________________________________________
____________________________________________________
8.
Now you need to write a detailed step-by-step procedure that describes exactly how you are going to carry out the
experiment. It needs to be clear enough so that someone else could read your instructions and do the lab. Write your
procedure like a set of instructions, in the second person. Do not write it in a narrative style.
You also need to start with a list of ALL equipment you will need, including the amounts.
Materials
50 mung beans
4 petrie dishes
paper towels
thermometer
ruler
Procedure
1. Place 2 layers of paper towels in the bottom of 4 petrie dishes and add 10 ml of water to each.
2. Place 10 seeds I each dish
3. Put the dishes in the 4 different temperatures: 10, 20, 30, 40 degrees Celsius. Cover each dish and keep it in a dark
place.
4. Check each dish after 24 hours and count the number of seeds that have sprouted in each dish. A seed will be
considered to have sprouted if there is at least 1mm of root showing. Remove seeds that have been counted so they are
not recounted the next time.
5. Continue to collect data for 4 days, checking the dishes everyday at the same time.
Controlled variables:
What variables did you control ?
How did you control them ?
9. Be ready to collect your data in a data table. Data tables MUST have the following:
Title
Headings
Units in the heading
Only #’s or observations in the cells
If you have more than one table it needs to be #ed.
DATA TABLE- practice by creating a data table for my experiment
Now put this all together and write your design for this lab. You will be graded on the rubric attached. Remember that if
you use a reference to support your hypothesis (which you should), it needs to be referenced appropriately- in the text and
have an accompanying bibliography.