the nature of science experimental investigations
TRANSCRIPT
The Nature of Science
Experimental Investigations
Making ObservationsTo make a Data Table:
QUANTITATIVE observations
Observations of Bubble Tubes
Label the type of observation
Give your table a TITLE
Bubble ????
Make room for recording your
DATA
Making ObservationsTo make a Data Chart:
QUALITATIVE observations
Observations of Bubble Tubes
Label the type of observation
Give your chart a TITLE
Bubble
Make room for recording your
DATA
Facts, Opinions, Inferences
• Fact – Is true for everyone
• Opinion – Personal belief that is not founded on proof
• Inference– Conclusion based on observation
The Pre-experiment Stage
Asking Questions
Developing Hypotheses
Watch & Listen Carefully
Bubble Tube Questions
• Does the color of the liquid make a difference in how fast the bubble moves?
• Does the angle of the tube make a difference in how fast the bubble moves?
• ?????????
Using Effect & Affect
• Does the color of the liquid affect the speed of the bubble?
• What is the effect of the color of the liquid on the speed of the bubble?
• Does the angle of the tube affect the speed of the bubble?
• What is the effect of the angle of the tube on the speed of the bubble?
Hypothesis
• If the angle of the tube increases, then the speed of the bubble will increase.
• If the angle of the tube decreases, then speed of the bubble will increase.
Experimental Stage
Designing an Experiment
Collecting Data
Watch & Listen Carefully
Designing an Experiment
• Identify variables– Independent / manipulated :
• Angle of tube• ?????
– Dependent / responding:• Speed of bubble
– Controlled / constants:• Person timing• Person handling tube• ?????
The Design
• What was being changed?
• How was it being changed?
• What was being measured?
• How was it being measured?
• How many trials were done?
Making a Data Table
Angle # 1 Angle # 2
Give your table a TITLE
The effect of angle on the speed of a bubble
Label your specific independent
variables
Make room for recording the
dependent variable
Data CollectionTitle
IV 1 – color of tube
IV 2 – Angle of the tube
Place to record data or dependent variable
Place to record data or dependent variabls
Post Experimental Stage
Data Analysis
Drawing Conclusions
Watch & Listen Carefully
The Question –Does the angle of the tube affect the time it
takes the bubble to move from one end of the tube to another?
• TWO independent variables– ANGLE of tube– COLOR of liquid in tube
• ONE dependent variable– Time or speed
• Controlled variables– Same timer, same ‘flipper’
Data Analysis
• Reduce the data– Measures of central tendency
• Mean• Median• Mode• Range• Frequency
Graphing the Reduced Data
• Line graphs show us change or trends– Why was a line graph an appropriate graph
for our data?
Use appropriate scale and interval
The effect of …….
Include all independent /
manipulated variablesand label
Angle 1 Angle 2 Angle 3
Angle of tube
Time of travel (sec)
Show dependent / responding variable
and unit of measurement
Include a descriptive title
Graphing Data
Look for Relationships
• Variables are related if one of them changes when the other changes.– If a change in one variable affects the other
variable, then the two variables are related to one another.
• Direct relationship– Change in the same direction
• Indirect relationship– Change in opposite directions
Data Analysis
• Look patterns of change– As angles decrease, what happens to the
time?• Is this true for all angles?
– As angles increase, what happens to the time?
• Is this true for all angles?
– What kind of comparison can you make with the colors of the tubes?
Drawing Conclusions
• Data will support or not support your hypothesis
• Hypothesis is rejected or accepted – Never ‘right’ or ‘wrong’
• Answer the original question– Use evidence (data) to back up what you say
Elaborating, Expanding, Applying
• Sources of error
• What else could be done?