1-1 What Is Science Science is an organized way of using evidence to learn about the natural world. Science is a process, not a “thing.” Explain this statement. 3 Goals of Science 1. Provide explanations for the natural world 2. Use explanations to understand patterns 3. Make useful predictions about natural events

The Scientific Method The scientific method is not a simple set of steps followed by all scientists, all of time. The scientific method just describes a general style of investigation. Example: In the 17 th century there was a debate over what caused food to spoil. – Spontaneous Generation: living things, like maggots, could arise from nonliving substances. – Biogenesis: living things can only come from other living things.

1. Observing and Asking Questions Observation – involves one or more senses to gather data

It is important to use all of your senses to collect as much data as you can. Sight isn’t always enough!

1.Observing and Asking Questions Science usually begins with observations: – Quantitative – involves numbers, counting or measuring 3 meters 50 kilograms 35 degrees Celsius – Qualitative – involves characteristics that cannot easily be measured or counted, color or texture (describable) It smells like fresh baked cookies This feels cold This sounds really loud

Inference – a logical interpretation of data based on prior knowledge We don’t observe an inference. We use observations to create inferences. Quick practice Observations: I hear people screaming I smell cotton candy, popcorn, and hamburgers I see a lot of people Inference = ?

What are some qualitative and quantitative observations you can make of these skulls? How about an inference based upon your observations?

Goal: Make predictions using observations Create an experiment on paper Warm up: Make a qualitative and quantitative observation from the picture

Look at these two sets of animal tracks. List 3 OBSERVATIONS Make an INFERENCE

Make 3 OBSERVATIONS

Make an INFERENCE

1. Observing and Asking Questions – Example Observation: Flies frequently land on the meat a few days before maggots appear. The Observation leads to a question. – Example Question: Are the maggots produced by flies?

The Scientific Method 2. Inferring and Forming a hypothesis – Hypothesis: A possible explanation for a set of observations. – Not just an educated guess – Must be a testable statement Example: The maggots come from the flies not the rotting meat.

The Scientific Method 3.Setting up a controlled experiment Variables: factors that can change. – Independent (manipulated) variable: the variable that the experimenter changes. – Dependent (responding) variable: changes in response to the independent variable. Can be measured. Francesco Redi used this simple experiment to test the hypothesis. What is the independent variable? What is the dependent variable?

The Scientific Method Experiments are usually divided into two groups: – Experimental Group – the independent variable has been changed. – Control Group – exactly the same as the experimental group except the independent variable has not been changed. Experiment without the variable. Why is the control group important for a good experiment? What is the experimental group? What is the control group?

Scientific Method 5. Drawing Conclusions – Researchers use data as evidence to determine if the hypothesis needs to be supported or refuted. – Ex: Maggots only appeared in the flask that was open to flies. – Do the results support the

When Experiments Are Not Possible How do we learn about animal behavior in the wild? Answer: Field studies – watching the animals without disturbing them. Some experiments are prevented because of ethical considerations. Think of an example. Stanford Experiment

Elements of a Good Graph Scaling and Increments are even Neatness and Accuracy counts Title (should include I.V./D.V.) Labeling of X and Y axis No squiggle line Use a ruler “DRY MIX” D = dependent variable R = responding variable Y = graph information on the vertical axis M = manipulated variable I = independent variable X = graph information on the horizontal axis

1-2 Communicating Results Publishing your research in scientific journals allows scientists to share ideas and to test/evaluate each other’s work. – Scientist, John Needham, reviewed Redi’s experiment and thought that he could show that bacteria grows through spontaneous generation. He boiled broth in an open flask to kill all bacteria. After several days more bacteria grew in the flask. What is the problem with this experiment?

Communicating Results Scientist, Lazzaro Spallanzani, reveiwed Needham’s experiment and hypothesized that the bacteria could have come from the air. – He repeated Needham’s experiment but he sealed the flasks. – Showed that bacteria did not grow in the broth, and supported biogenesis. Scientists did not accept Spallanzani’s conclusions. Why not?

Louis Pasteur Scientist continued to debate about spontaneous generation until Because scientists published their experiments they critique and improve on the design. Louis Pasteur repeated the experiment but this time he used a flask that would let air in but keep out bacteria. Did Pasteur’s results support biogenesis or spontaneous generation? Explain how this process of communicating results improves our understanding?

How a Theory Develops Theory – a well-tested explanation that ties together many different observations and hypotheses. – No theory is considered absolute truth because science is always changing. – Biogenesis is a well tested theory – How is the scientific use of the word “Theory” different than the everyday use of the word theory.

Scientific Terms Law: A statement or equation that summarizes observations without explaining them. Examples: – Law of conservation of matter – Laws of inheritance