基礎生物實驗 1 - 實驗一簡介：Experimental Design
新坑！這一部分實驗的內容將放在生物基礎與進階文集的基礎部分之后。這一部分的內容旨在介紹生物實驗的基本方法，并提供線上虛擬實驗的獨特體驗。本期是第一期，內容是實驗設計的理論基礎。下一期將是實驗一的實驗手冊、下下期則是實驗模擬（中文）。
本部分內容來自 University of California, Berkeley - UC Berkeley?Extension, 虛擬實驗的內容來自 Labster. 本部分內容均不會標記為為原創(chuàng)，但由于是UP主購買的課程，因此不接受非授權的轉載，謝謝您的理解。
每一個生物基礎實驗均會分為三部分：第一部分為實驗的生物理論；第二部分為實驗的指導手冊；第三部分為 Labster?的虛擬實驗模擬。第一部分的基本信息由 Ying Liu, Ph.D. 提供，第二部分的實驗手冊來自 Labster, 第三部分的實驗模擬過程由UP主操作。
Lab 1?- Experimental Design:?Basic Information:
[1] Lab Safety & Housekeeping
Lab safety
????- Wear closed-toe shoes
? ??- Long hair tie back
Locate safety items
Lab cleanup pROCedures
????- Wipe the bench clean before and after work
????- Glassware
????- Equipments
????- Different (biohazard) wastes
[2] Metric System
????- Official system of measurement in almost every country in the world
????- Developed by the English in 1600s
????- First adopted by the French after the Revolution
????- US is the only industrialized country that has not adopted it!
Base units for measurements: meter, liter, gram
Units are related by factors of 10, and denoted by standard prefixs (e.g. milliliter (ml), kilometer (km), microgram (μm)
Universally used in sciences
Metrix vs. English System
Conversion in Metric System
Move the decimal point: The right direction & The right number of places
Example: 100 μL? =? ? mL - μL=10^-6 L, mL=10^-3 L
[3] Experimental Design / Scientific Method
Elements of a Scientific Approach
Observations lead to a question
Hypothesis is the tentative answer or explanation
????- Must be testable and falsifiable
????- Cannot be proved
Prediction is made based on hypothesis and experiments designed to test it (think: if…then…)
Bad vs. Good Questions
- Good questions are: Well defined, Measurable (testable), Reasonable, Consistent with existing bodies of knowledge, and Falsifiable
- Bad questions are broad or do not have a clear answer, example: "Is nicotine bad for you?"
- A good scientific question has a narrow, unambiguous answer: "Does nicotine cause lung cancer?"
Science as a Way of Knowing
- Observation: my neighbor’s lawn looks more healthy than mine. Hmmmm…
- Question: Does the amount of water we each put on our lawns account for the difference?
- Hypothesis: My neighbor’s lawn is more healthy because it gets more water than mine
Design an Experiment
VARIABLES:
????Independent: factor being manipulated for effect on dependent variable (experimental condition)
????Dependent: the response being studied
????Controlled (confounding): other factors that experimenter holds constant??
PROCEDURE:
????Level of treatment-- value or range of the independent variable
????Control-- parallel pROCedure in which the independent variable is set or omitted
????Replication-- one comparison not enough!
Performing the Experiment
- Prediction: IF a lawn gets more water, THEN it will be greener and grow faster than a lawn with less water (you have determined how you will measure ‘healthy’)
- Do the experiment
- Collect and analyze data
- Repeat the experiment?
- Publish / communicate with the scientific community?
Hypothesis vs. Theory
????Hypothesis: tentative answer to a rather narrow question
????Theory: well-supported, broad explanation
A scientific theory is much broader and better supported than a hypothesis.
A scientific theory is:
????- Broad in scope – a big idea!
????- General enough to generate new hypotheses
????- Supported by a large body of evidence
Some well-known theories in biology: Cell theory, Germ theory of disease, Theory of evolution by natural selection, etc.
Graphing Results
????- Independent variable plotted on x-axis
????- Result (dependent variable) plotted on y-axis
????- Statistics (standard error) tells us how uncertain a particular value is
Line vs. Bar Graphs
????- Line graph: used to show changes that occur in related variables, and trends over time
????- Bar graph: compare data (measurements) from different groups, can show large changes over time
Experimental Design
Learning objectives:
????Explain and apply the scientific method
????Design an experiment and test your hypothesis
????Correctly use experimental controls
感謝閱讀！下一期為實驗手冊 & 下下期將進行 Labster 實驗！
