Introduction to Biology The Nature of Science

Starter Syllabus and Lab Safety Contract are due today!! Have them out and ready to turn in. Get out a piece of paper. Write your name and class period in the upper right corner. Title it “Intro to Chemistry and Measurements Starter”. Put todays date in the left hand margin. Answer the following questions in full sentences. Be prepared to share your answers. How many days do you have to turn in an assignment when you have an excused absence? How many late assignments are you allowed per quarter? Why would you not want to use a beaker that looked spotted or dirty in the lab? Don’t know or are unsure of the answers? You can use your notes, your textbook, or your shoulder neighbor (quietly).

Lab Safety Test Review

Notes on Notes

Why do we take notes?

Why do we take notes? Information is forgotten in as little as 20 seconds. ½ of what is learned is forgotten within 1 hour. By day 2, if you do not think about or review your notes, you will lose up to 80% of what you have learned. By day30, if you do not think about or review your notes, you remember only 2%-3% of what you learned.

When should we take notes?

When should we take notes? The speaker says to take notes The speaker says something you don’t already know The speaker presents using a PowerPoint The speaker writes on the board The teacher says, “This will be on the test.”

Cornell Notes Cornell notes is a method to capture the most important information when reading texts or listening to a lecture. Helps you retain more of what you learned. When used it has been proven to improve grades. Students who take and use Cornell notes as a study tool retain 90-100% of what was learned. Set up your paper Take the notes Apply your thinking to the notes Reflect, revise, and review your notes

The Nature of Science

What is Science?

What is Science? Science is both a body of knowledge and a process. Science: the systematic study of the natural world through observation and experiment.

Observations and Inferences A scientific investigation usually begins with curiosity about something observable. Modern science is based on observation and inference. Observation: seeing and noting facts Inference: a proposed conclusion based on based on observations and facts

Observation Observation: seeing and noting facts

Inferences Inference: a proposed conclusion based on based on observations and facts

Observation Observation: seeing and noting facts

Inferences Inference: a proposed conclusion based on based on observations and facts

In Science Observations Inference When we describe an environment based on our five senses, it is called an observation. Observations are direct enough that most would make the same observation in the same situation. Example: "Upon magnification, the painted lady eggs appear bluish and barrel-shaped." Inferences When we bring our past experience into making a judgment based on an observation, it is an inference. Example: "The caterpillar appears as if it is about to form its chrysalis" is an inference, because you are interpreting observations according to knowledge from past experience. Inferences are important in science in making explanations.

Hypothesis & Predictions Hypothesis: a testable explanation for a natural phenomenon A hypothesis explains what you expect to happen It must be testable and measurable Prediction: statement of some condition that should exists if the hypothesis is correct The if part is the hypothesis and the then part is the prediction

Experiment Next scientist devise ways to test a prediction Experiments: tests designed to support or falsify a prediction A typical experiment explores a cause and effect relationship by changing variables (the if…then…) Variables: in an experiment the characteristic differs

Variables Independent variable: variable that is controlled by the experimenter in order to explore its relationship to a dependent variable – what you change Dependent variable: variable that is affected by an independent variable being tested - what you observe Controlled variable: variable that is constant and unchanged throughout the investigation – what you keep the same

Variables You water three sunflower plants with salt water. Each plant receives a different concentration of salt solution. A fourth plant receives pure water. After a two week period, the height of each plant is measured. Identify the following: Independent variable: Dependent variable: Control group:

Variables You water three sunflower plants with salt water. Each plant receives a different concentration of salt solution. A fourth plant receives pure water. After a two week period, the height of each plant is measured. Identify the following: Independent variable: salt water solution Dependent variable: Control group:

Variables You water three sunflower plants with salt water. Each plant receives a different concentration of salt solution. A fourth plant receives pure water. After a two week period, the height of each plant is measured. Identify the following: Independent variable: salt water solution Dependent variable: height of the plants Control group:

Variables You water three sunflower plants with salt water. Each plant receives a different concentration of salt solution. A fourth plant receives pure water. After a two week period, the height of each plant is measured. Identify the following: Independent variable: salt water solution Dependent variable: height of the plants Control group: 4th group that received pure water

Experiment Data: experimental results Data inconsistent with the prediction are evidence that the hypothesis is incorrect and should be revised. A necessary part of science is reporting results and conclusions

Scientific Method Scientists usually do not walk through the method sequentially.

Scientific Method The scientific method is an ongoing process. Scientists often bounce around, perhaps forming a new hypothesis during experimentation. Studies in which no experimentation is performed are also valid scientific studies, but do not follow the scientific method. For example: Jane Goodall observed the behavior of the apes in Africa and did not experiment on them, yet her research is still considered science.

Scientific Method

Scientific Theory It’s Just a theory In everyday language ‘theory’ means a hunch or a guess. A ‘scientific theory’ refers to a well supported explanation. A scientific theory differs because it is supported by a large body of evidence, and it is consistent with all known facts

Scientific Theory Scientific theory: an explanation for an observation that is supported by evidence It is consistent with all data ever gathered It is our best descriptions of the natural world, but can never be proven absolutely because it would mean that it would have to be tested under every possible circumstance Example: To prove the atomic theory the composition of all matter in the universe would have to be checked Like a hypothesis a scientific can be disproven by one observation or result that is inconsistent with it

Scientific Knowledge is Tentative Although scientific knowledge is supported by a wealth of data from repeated trials, it is not considered the final word. Scientific knowledge is at the same time stable and changing. Scientists continually test and challenge previous assumptions and findings. Science is a human endeavor, and we know human perspective is limited and fallible.

What Science is… Focuses on the natural world Aims to explain the natural world Uses testable ideas Relies on the evidence Involves the scientific community Leads to ongoing research

Limits of Science… Science does not make moral judgments Science does not make aesthetic judgement Science does not tell you how to use scientific knowledge Science does not draw conclusions about supernatural