The Nature of Science Experimental Investigations

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?