QOTD 9/9/14 1. Pick up a safety quiz (do not write on it!) and an answer sheet. Take the quiz- 10 minute time limit! 2. Return the quiz and your answer key. Pick up a “clicker”. 3.Find your response to yesterday’s QOTD (“doing science”). Use the clicker to input your choice: A, for Antoine, B for Tamara, C for Marcos, or D for Avery.

Learning Targets Be able to distinguish between an observation and an inference Be able to describe how science is done Be able to describe the “scientific method”

How science works How science works: not just experiments (6 min) California Academy of Sciences Thinking like a scientist: number pattern o&list=PL16649CCE7EFA8B2F (5 min) Veritasium o&list=PL16649CCE7EFA8B2F

SCIENTIFIC METHOD Send a group member to get a notes sheet for each group member.

SCIENTIFIC METHOD The scientific method is an organized way to solve a problem or answer a question. You probably use it every day without even thinking about it. It is NOT a “follow the steps” method; but often we can do science by following some generalized steps…

The Problem or Question What do you want to find out? What problem are you trying to solve? State your problem or purpose as clearly as possible. Does your problem have more than one part?

Observations / Research An observation is when you use your senses to gather information about your problem. Use your past experiences as a resource. Research is an important part of gathering information. Quantitaitve = numbers/measurement Qualitiative = quality, color, etc.

Observation vs. Inference An inference is a conclusion reached based on evidence or reasoning. Be careful not to confuse an observation with an inference! For example: There is a long line at the restaurant. This is an observation. The food is good at the restaurant. This is an inference.

Observations and Inferences identify each statement as either a qualitative observation or quantitative observation, or as an inference. - You have 3 minutes… 1.Linus is looking at the puddle of water. 2.Linus is thinking as he studies the puddle. 3.Linus stomps angrily on the puddle. 4.Some water evaporated from the puddle. 5. Linus produced more than 6 small puddles when he stomped. 6.None of the puddles are the same size as the original. 7.If all the puddles were recombined, it would be the same size as the original puddle. Qualitative observation – can’t be measured inference Quantitative observation – counting Quantitative observation – you can measure the size inference

Scientific Hypothesis A possible solution to the problem based on your observations, research, and past experience. Allows you to make a prediction: “If ___X___, then _______Y____ will happen because __Z____” Often called “educated guess”, but this is not a good definition! A good hypothesis is much more than just a guess!

Hypothesis Must be testable and falsifiable. If it is impossible to test your guess or prove that it is false, then it is NOT a scientific hypothesis! testable example: “Cactus spines reduce the amount of damage caused plant eaters” “if we remove the spines of some cacti, then more of them will be eaten” – we CAN test this!

Hypothesis non-example untestable example: anything involving supernatural forces, morality, religion, etc. (spirits, psychics, ghosts, God, etc.) Science ONLY deals with the natural world and can ONLY answer testable and falsifiable questions!

Experiment An scientific experiment is a way to test a hypothesis. Either proves the hypothesis wrong (falsifies it) or it supports the hypothesis. An experiment NEVER proves the hypothesis right!

Experiment (cont’d) A variable is a factor that can be changed in an experiment. Independent (manipulated) variable – what you change on purpose Dependent (responding) variable – what happens as a result of changing the independent variable A control variable remains the same during the entire experiment.

A Controlled Experiment For an experiment to be valid, it must be controlled. During a controlled experiment only one variable is changed at a time. The scientist must contrast an experimental group with a control group. The two groups are treated EXACTLY alike except for the ONE variable being tested.

Replication, sample size, and reliability Procedure is repeated several times to see if results are consistent. Results from different trials are averaged. Often large numbers of trials or large samples are taken. More replication and large sample size = more confidence in the result A reliable experiment is one that is done in the same way each time and gets the same results.

Results Make necessary graphs Analyze the results. Do they make sense?

Conclusion Was your hypothesis supported or falsified? What did your experiments tell you? Do you need to do further experiments? If your hypothesis was not supported, you would change your hypothesis and do a new experiment. If your hypothesis was supported, it does NOT mean you were correct! It just means you might not be wrong! Other experiments might show that you weren’t right after all!