Scientific Method https://www.youtube.com/watch?v=moeVjt3dVQo

Unit 1 lecture 1- Doing Science Four students were having a discussion about how scientists do their work. This is what they said… Antoine: “I think scientists just try out different things until something works” Tamara: “I think there is a definite set of steps all scientists follow called the scientific method” Marcos: “I think scientists use different methods depending on their question” Avery: “I think scientists use different methods but they all involve doing experiments” Which student do you most agree with? Explain why. Also include why you disagree with the other students.

Unit 1 - lecture 1- scientific method The various parts of the scientific method. Scientific method: - a way of solving problems using a systematic approach

Key Points: Observation/Problem: Something that you notice/wonder Can be… * Qualitative: no number involved Ex. The water is warm *Quantitative: measured with numbers Ex. The water is 670C

Hypothesis: a possible explanation for an observation based on Research (NOT a random guess!!!!)

They produce… Experiment: Something that we do to test our hypothesis. Data (new information) Conclusions (based on data to support or negate hypothesis) Theory model (explanation for an observation) Based on tested hypotheses and often change Natural Law (summary of observed behavior)

Experiments need good design… 1. Variables Independent variable The factor being tested Dependent variable The factor being measured Control variables Factors being controlled (not changed between different experiments)

2. When using groups Control group - does not get Independent variable experimental group - same as control but gets independent variable. 3. Repetition (experiments should be repeated to verify data)

You are interested in understanding the effect of the solute sodium chloride (table salt) on the boiling point of the solvent water. You add salt to water in pot #1 and no salt to water in pot #2. You heat the two pots. Pot #1 boils at 1050C and pot #2 boils at 1000C. Identify the: Control group: 3. Independent variable: 2. Experimental group: 4. Dependent variable: 5. Control variable/s