Section 1.3—Designing Your
Own Labs
Designing Labs
 This is not giving a “scientific method”…rather
it’s giving hints at how to stay focused on the
goal when designing a lab to allow you to write
them more efficiently
 It gives you a plan of attack, but you can adjust it
as you need for various labs
Identify the purpose, problem, question
 If variables are appropriate (relationship or effect
lab), identify them in the problem
Example of a purpose: To determine the effect of
temperature on pressure
 If variables are not appropriate, be as
descriptive as possible
Example of a question: What is the concentration of a
saturated NaCl solution at room temperature?
 You can phrase it as a purpose or question
 You should also identify any important constants
Gather Background Information
 The background information section is where
you put together all the different concepts you
know together to solve your problem or answer
your question
 It might contain:
Definitions
Known relationships
Equations
Write a hypothesis
 Only when appropriate—only in relationship or
effect labs
 After looking at all your background information,
make a hypothesis (prediction with explanation
for why you think so)
Set-up the Results/Calculations section
 Write any equations that you will need to solve
your problem or answer your questions.
 You won’t have numbers to plug in, but you can
set up the equations/calculations now.
Set-up the Data Table
 Go through the calculations you set up and make a data
table that asks for each quantity you’ll need
 Remember that some measurements must be taken
indirectly & you will need to take that into account:
For example, you can’t put a chemical directly on the
balance, so you’ll need the mass of the container
(beaker or weighing dish) and then the mass of the
container & chemical in your data table
 Your data table should not contain any calculated values
(even just subtracting out the mass of the beaker)…only
those you will actually measure with an instrument!
Write your Procedure
 Procedures should be:
 Clear, Concise, Numbered list of steps
 Repeatable by someone of your same level of
experience/education
 Go through your data table and write a procedure
step to measure each thing asked for in your data
table.
 If the data table includes masses or volumes of
chemicals, give an approximate amount in the
procedure
 Example: Add approximately 2 g of NaCl to the beaker.
Find exact mass & record.
Write your Materials List
 Go through your procedure and make a list of
each piece of equipment and chemical that
you’ll need
 Be sure to include how many of each type of
equipment and what approximate quantity of
chemical
You don’t need to specify the amount of water
needed!
Write your Safety Concerns
 Go through your procedure & materials list
and specify any safety concerns.
 Possibilities include:
Wear goggles (anytime you use glass or chemicals)
Use caution with glassware
Use caution with hot glassware or hot chemicals
Any cautions specific to a chemical you’re using
(your teacher will tell you these)
Report any spills, breaks or incidents to your
teacher immediately
Wear aprons or gloves, if necessary
Now you’re ready to do your lab!
 Begin performing your lab (after your teacher
checks it for safety, if necessary)
 If you need to make changes to your
procedure at any time (you realize it’s not
quite right)…that’s OK
Just make sure you change the written procedure
as well so that when you’re done, the written report
reflects what you actually did
 Record your data in the data table
 Complete the calculations you’ve set up
Write your Conclusion
 Restate the purpose
 Completely answer the purpose with your
results
 Address any earlier hypothesis…does your
evidence support or not support it?
If it does not support the hypothesis, propose a new
hypothesis
 Suggest possible sources of error
“human error” is not specific enough & “Calculations”
doesn’t count