Introduction to Science for Biology Students Measurement The 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 cmmm

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 Problem 2. Do Research 3. Make a Hypothesis 4. Conduct an Experiment 5. Collect and Measure Data 6. Analyze Data 7. 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 rateHeart 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

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.