The Nature of Science
Experimental Investigations

Making Observations
To make a Data Table :
QUANTITATIVE observations
Give your table a
TITLE
Observations of Bubble Tubes
Label the type of observation
Bubble ????
Make room for recording your
DATA

Making Observations
To make a Data Chart :
QUALITATIVE observations
Give your chart a
TITLE
Observations of Bubble Tubes
Label the type of observation
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
Label your specific independent variables
Give your table a TITLE
The effect of angle on the speed of a bubble
Angle # 1 Angle # 2
Make room for recording the dependent variable

IV 1 – color of tube
Data Collection
Title
IV 2 – Angle of the tube

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?

Graphing Data
Include a descriptive title
The effect of …….
Use appropriate scale and interval
Time of travel
(sec)
Include all independent / manipulated variables and label
Show dependent / responding variable and unit of measurement
Angle 1 Angle 2 Angle 3
Angle of tube

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?