Scientific Cents

Making Observations

• Work with your partner

• Read the procedure carefully.

• Make a data table and a data chart to record your observations before you begin.

Making Observations

To make a Data Table:

QUANTITATIVE observations Observations of Pennies

Label the type of observation

Give your table a TITLE

Make room for recording your

DATA

Making ObservationsTo make a Data Chart:

QUALITATIVE observations

Observations of Pennies

Label the type of observation

Give your chart a TITLE

# of ????

1

2Make 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

Research Questions

• Use effect or affect– How does ___?___ AFFECT ___?___ ? independent variable dependent variable

– What is the EFFECT of ___?___ on ___?___ ? independent variable dependent variable

Scientific Cents Question

How does the amount of soap in water affect how much water can be dropped on a penny?

What is the effect of different amounts of soap on how much water a penny can hold?

I.V.

I.V.D.V.

D.V.

Hypothesis

• Use an If, Then statement.

If the independent variable changes, then the dependent variable will change.

Hypothesis

If the amount of soap increases, then the amount of water will increase.

If the amount of soap increases, then the amount water will decrease.

Experimental Stage

Designing an Experiment

Collecting Data

Watch & Listen Carefully

Experimental Design• All variables must be identified

– Independent / manipulated• Water / soap mixture

– Dependent / responding• Number of drops

– Controlled / constants• Same size drop• Same dropper• ??????

Experimental Design

• All materials must be identified– Quantities

Experimental Design

• EVERY step must be explained– “test the penny” is not a step because there

is no explanation of how to test.

• There must be an explanation of what data will be collected, and how it will be collected

Experimental Design

• Include how many trials will be conducted

Experimental Design

• Do not include:– Gather materials– Make a graph– Draw conclusions

Data TablesMixture #

1Mixture #

2Mixture #

3

1

2

3

4

5

Mean

Record Dependent / Responding

variable (Data) Here

Show # Independent / Manipulated

variable

Show # of trials

Post Experimental Stage

Data Analysis

Drawing Conclusions

Post Experimental Stage

Data Analysis

Drawing Conclusions

Watch & Listen Carefully

Use appropriate scale and interval

A comparison of …….

Include all independent /

manipulated variablesand label

M 1 M 2 M 3

Type of Mixture

Number of

drops

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

Graphing the Reduced Data

• Bar graphs show us comparisons– Why was a bar graph an appropriate graph for

our data?

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?