What Is Science? s1

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What Is Science? s1

What is Science?

Brainstorm: In small groups list all of the characteristics that help define science from other subjects. Once you have completed your list of what is science, then try to generate of list of things that would not be considered science.

What IS Science? What ISN’T Science?

Your Definition: With your group, use your brainstorming ideas to create your own complete definition of science.

Our Definition: Your teacher will provide you with a more universal definition of science. Write it down. The Scientific Method Science starts with curiosity! o Scientists are keen observers of the world and are curious about how it works o Once a problem or central question is found, a scientist will seek evidence of the answer

What sorts of questions could you ask about this light bulb?

Light bulb

Hypothesis

o All good science starts with a testable prediction o A hypothesis is an informed prediction which can be tested by experiment o It must be falsifiable! (This means it can, in theory, be proven wrong) o Often we use “if/then” statements

examples: “If the weather is humid, then a Frisbee will travel further when thrown.” “If car tires are kept at equal pressure, then the car will use less gasoline.” “Honey bees will be more likely to visit blue flowers than red flowers.”

Invalid: “If vegetables are vacuum sealed, then they will be better”

Corrected: ______

Invalid: “Women are smarter than men.” Corrected: ______

Try your own… write a hypothesis that could be tested to answer the following question: “Does whitening toothpaste really work?”

______Law

o A set of observed regularities expressed in a concise verbal or mathematical statement o A law states what happens in nature – it usually does not attempt to explain reasons why. o A law requires no theoretical basis. (i.e. it does NOT require an explanation)

examples: Law of conservation of matter ~ matter cannot be created or destroyed Ohm’s Law ~ V = IR or voltage = current x resistance

Theory

o An explanation for an observation or series of observations that is substantiated by a considerable body of evidence o A theory is used to: . Explain why certain observations occur . Predict what observations will occur in future experiments

Some ideas from a variety of Extinction theories: “Dinosaurs became extinct as a result of a cooled climate caused by a large meteor impact and a series of large volcanic eruptions.”

Part of the Theory of Evolution: “All living creatures on Earth use DNA as their genetic material because they evolved from a common ancestor”

Some other important scientific theories: Atomic Theory Cell Theory The Theory of Relativity

We cannot say a theory is true or false. We can only say it is supported or not supported by scientific evidence

What do scientific laws and theories have in common?

Both are based on tested hypotheses Both are supported by a large body of empirical data Both help unify a particular field Both are widely accepted by the vast majority (if not all) scientists within a discipline. Both could be shown to be wrong at some time if there are data to suggest so.

Scientific knowledge is strengthened by people questioning what is or has been accepted. It may be hindered by questioning without scientific evidence. Scientific Inquiry In Short

Typical sequence of experiments: Scientific Method Planner Laws, Theories and Hypotheses Practice

Part 1: Identify the following as a law, theory, or hypothesis: (a) Energy cannot be created or destroyed law theory hypothesis (b) If students complete their daily homework, law theory hypothesis then they will perform better on tests. (c) Ice floats on water because it is less dense than law theory hypothesis liquid water (d) Atoms combine in definite proportions law theory hypothesis

Part 2: Form a hypothesis for the following situations. Use If / then statements. 1) You noticed that your car stops faster in the snow when it has winter tires. You want to test this observation. What is your hypothesis?

______2) A teacher noticed that the scores on tests were lower when students reported not sleeping enough the night before the test. ______3) The dentist told you that your chances of getting cavities are higher if you don’t brush your teeth twice a day. You have your doubts and want to test this. What is your hypothesis? ______

Part 3: Assuming your hypotheses are correct propose a theory to explain each of them. (Note: in real science, we cannot “make up” a theory, it must be based on experimental results and/or strong evidence.)

1) ______

2) ______

3) ______

Part 4: Mary’s Shirt Solution Read the story below and answer the questions that follow on a SEPARATE PAGE.

Mary is in charge of dying T-shirts for the cheerleaders to wear at the next pep rally. She has 10 white, 100% cotton T-shirts and wants to dye them to match the orange border on the cheerleader shirts. Mary buys a box of orange Ritz dye.

Mary is not sure how to dye the shirts the exact color of the skirts. She reads the dye label and discovers that the length of time that cloth is soaked in the dye will determine the shade of the color that the cloth will become.

She guesses that soaking the shirts for about fifteen minutes should be long enough to dye them the proper shade of orange. But she is still uncertain. She decides to use one extra shirt to test her prediction.

Mary cuts the shirt into 10 six inch squares. She places 2 grams of orange Ritz dye into 500 milliliters of water. She measures the temperature of the water and finds that it is 28º C. She places the squares of cloth into the bowl, making sure that each one is covered by the dye solution. She sets a timer and removes one square of cloth every 5 minutes. She labels each square and allows them to dry for three hours.

Mary observes the squares to discover which one best matches the skirts. She finds that the square that was soaked for 35 minutes is the best match.

Follow-up Questions: 1. What question did Mary have about dying the T-shirts? 2. Where did she find information about the Ritz dye? 3. How much time did she predict the shirts should be soaked? 4. Describe the experiment that she designed to test her prediction. 5. What was one thing that she did differently to each piece of cloth in her experiment? 6. List the ways that each piece of cloth was treated exactly the same in her experiment. 7. What did Mary observe? 8. Was her prediction correct? 9. How long do you think she decided to soak the 10 remaining T-shirts? 10. Why would it be important that Mary record how much dye she used, the amount of water she used, and the temperature of the water?

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