List three things you can remember about LAB SAFETY (4). Take a WARM-UP SHEET from the front table, find your assigned seat, and start the warm-up. Happy Monday! Warm-Up 1/28/13 List three things you can remember about LAB SAFETY (4).

The Scientific Method

What is SCIENCE? GOAL – Investigate and understand the NATURAL WORLD. Through investigation, we want to explain it. Science is an ONGOING PROCESS…

SCIENTISTS… Collect and organize data and information in a careful and orderly way. Propose explanations that can be tested.

The Scientific Method (SM) The scientific method is a set of common steps that biologists and other scientists use to gather information and answer questions Not a fixed, rigid set of steps – just basic guidelines…

The Scientific Method The SM is used to solve… questions and hypotheses that can be tested and that will create results that can be measured. ***What types of questions CAN be answered through scientific investigations?

1. Make an Observation The scientific method generally begins when observations are made Identify a Problem to be solved Ask a Question: How, What, When, Who, Which, Why, or Where? The question must be about something that you can measure with value.

Observation vs. Inference Observation: what you can physically see, hear, smell, taste, or feel Example: Steam rising from a cup of coffee Inference: an assumption or explanation you make for the observation Example: The coffee is hot

2. Construct a Hypothesis A hypothesis is a testable statement that explains the problem and predicts what will happen in the experiment Example: If (I do this), then (this) will happen You must state your hypothesis in a way that you can easily measure

Example Observation: Fertilizer seems to make plants grow taller Question: Does fertilizer help plants grow? Hypothesis: If a plant receives fertilizer, then it will grow taller than a plant that doesn’t receive fertilizer

3. Design a Controlled Experiment Your experiment tests whether your hypothesis is true or false. Variables: what changes or is manipulated during an experiment

What are independent and dependent variables and how are they related? INDEPENDENT variable: the variable in the experiment that is tested --- it affects the outcome of the experiment *Example: Amount of fertilizer The variable that “I” change

What are independent and dependent variables and how are they related? DEPENDENT variable: the variable that is measured or observed --- changes based on the independent variable *Example: How much the plant grows

Variables How many variables do I manipulate (or change)? Always only

Variables Can’t change 2 variables at the same time – if you change the amount of fertilizer AND sunlight, then how do you know which one is helping the plant grow? ? = +

3. Design a Controlled Experiment Experimental group: the trials in which you use or test the independent variable *Example: plants that you give different amounts of fertilizer 10 grams 20 grams 30 grams

Experimentation Control group: the trials where you leave out the independent variable *Example: plants that you give WATER instead of FERTILIZER

Experimentation Why do I need to have a control? Gives data unaffected by the variable being tested. Need to know what would happen if nothing was done to the subject being tested

Experimentation Constant(s): what remains the same throughout the experiment *Example: the same type of plant, the same size pot, the same amount of sunlight, etc.

4. Gather, Record, & Analyze Data Data: all measurements collected during an experiment Data can be: Qualitative –descriptive data, observational Describes qualities Ex: the solution turned purple; the desk is black Quantitative – numerical data, results from counts or measurements Describes quantities Ex: the pencil is 15 cm long; there are 25 plants

What’s the difference between qualitative and quantitative data?

Analyzing Data How do you analyze large amounts of data? Line Graph Bar Graph Pie Chart Can you think of other ways to analyze data?

Analyzing Data Dependent or responding variable is always on the Y axis Independent or (manipulated) variable is always on the X axis

5. Draw A Conclusion After analyzing and interpreting your data and results, conclude whether the hypothesis was right, partially right, or wrong.

Chauncey wonders if holding the laces of a football allows him to throw it farther. He predicts that he can throw a football twice as far if he puts his fingers on the laces as opposed to not. He stands at the goal line on a windless sunny morning and throws the same football three times without holding the laces and then three times while holding the laces. The table shows how far he threw each. What should his conclusion be?

5. Draw A Conclusion State whether your hypothesis is right or wrong. The hypothesis is true: Report your findings. The hypothesis is false or partially true: Report your findings. Think and try again.

6. Share/Communicate Results By publishing data, results, and conclusions, other scientists can repeat the experiment Review, reproduce and confirm your results Science is cumulative; one discovery is often made based on the work of others

Types of Communication Articles in magazines such as the AMA (American Medical Association) Presentations and Seminars Peer Review Can you think of others?

Theories and Laws A theory is an explanation of a natural phenomenon that is supported by a large amount of evidence – theories can be revised. Examples: Theory of Evolution Big Bang Theory

Theories and Laws A law is absolute and does not change. Examples: Law of Gravity Newton’s Three Laws of Motion Laws of Thermodynamics

Design an Experiment --- Biology Each group will receive a problem to solve using the scientific method. You may choose another problem to solve, but get approval from me before you start. You will design the experiment to test your problem as a group. Listen to all input and come to a consensus for all decisions.

Design an Experiment --- Biology Design the experiment following the steps of the scientific method and write it out following the layout of the lab report format. Make sure you include all of the following: Problem Statement Hypothesis Materials List Include amounts to be used (ex. 10 mL water) Procedure in detail Controlled experiment Experimental AND control group Independent and dependent variables What are your constants? Data Collection: How are you going to measure? When are you going to measure? How many are you going to measure? How are you going to analyze your data (what kind of graph)? Since you will not actually do the experiment, you will not be able to write a conclusion. However, explain how you will use your data to come to a conclusion and answer the problem statement.

Design an Experiment --- Honors Biology Each pair will develop a problem to solve using the scientific method, and you will design an experiment to test your problem. You may discuss the assignment with the people around you, but everyone should be working on a different subject.