Introduction to Science for Biology Students

MeasurementThe Scientific Method

Graphing

Lab Equipment

• Graduated Cylinder- Measures Volume- Place on table- Eye Level!!- Read at bottom of

curve (meniscus)

• Beaker– Measures volume– Not as accurate

• Flask– Measures volume– Not as accurate– Good for mixing

• Balance– Measures mass– Uses grams– Must “zero” it

• Ruler– Use CENTIMETERS (cm) or MILLIMETERS (mm)– There are 10 millimeters in every centimeter

cm mm

The Scientific Method

*BREAK*

• Problem: I’m cold.

• Think of some questions that you might ask me in order to solve my problem.

What is the Scientific Method?

• A step-by-step way to solve problems

Steps:

1. State the Problem2. Do Research3. Make a Hypothesis4. Conduct an Experiment5. Collect and Measure Data6. Analyze Data7. Make a Conclusion

1. State the Problem

• The question you are trying to answer• Based on observations you have made

– Observations are made by using your senses (sight, sound, touch, etc.)

– Observations are facts!– Inferences are opinions, or assumptions, based on

your observations

Observations vs. Inferences

1. State the Problem

• Usually the problem is written as a question• Ex:

What affect does caffeine have on your heart rate?

2. Do Research

• Examples of Research:– Newspaper article– TV program– Ask an expert– “Google” It

3. Make a Hypothesis

• States the expected answer to the problem– What do you think the experiment will show?

• Must be able to be tested!

• Written in an “If…. Then…” format

If you drink a soda with caffeine, then your heart rate will be higher than if you drink a soda without caffeine.

4. Perform an Experiment

• The procedure used to test your hypothesis

• Hypothesis: If you drink a soda with caffeine, then your heart rate will be higher than if you drink a soda without caffeine.

• Your experiment needs to have:– Sodas with caffeine– Sodas without caffeine– People to drink the soda and measure their heart rate

• In an experiment, you test one variable at a time– A variable is something that changes

Independent Variables (IV) – what YOU change on purpose; is known before the experiment

Dependent Variable (DV) – what you measure in the experiment; is NOT known before the experiment

Controls: a variable that you keep the same throughout the experiment

Variables

• In our experiment, we have:– Sodas with caffeine– Sodas without caffeine– People to drink the soda and measure their heart

rate

• What is the Independent Variable?• What is the Dependent Variable?• What are some controls?

Answers..

• IV = caffeine• DV = heart rate• Controls = same amount of soda, same age

people, possibly same gender, same amount of time, or same person

5. Collect and Measure Data

• There are two types of data:– Quantitative = numbers– Qualitative = descriptions

• What type of data would… be…– The plant is green– The plant is 2cm tall

6. Analyze Data

• Once you have measured your data, you can arrange it in graphs or tables

- This will allow you to see any trends in your

data

Caffeine

No Caffeine

Heart rate

Graphs• There are 3 types of graphs:– Line = shows information over TIME– Bar = shows ONE TIME information– Circle/Pie = shows percentages or parts of a whole

Hamburgers Hot Dogs Corn Dogs012345

Students

Students

8

10

2

1 3

Grades

ABCDF

7. Form a Conclusion• You summarize what you discovered in your

experiment• You state whether your hypothesis was correct

or incorrect• Written in complete sentences!• Ex:

A person’s heart rate is higher after drinking a soda containing caffeine than after drinking a soda that does not contain caffeine.