scientific evaluation being objective. measurements 0 taking accurate measurements is only one...
TRANSCRIPT
Scientific Evaluation
Being Objective
Measurements
0Taking accurate measurements is only one aspect of scientific experiments
0When recording measurements, be sure to list the units
0 Important to indicate whether you measured in metric or English units
The Metric System0How the world communicates the results of its
experiments0Decimal system of measurement0All units divisible by 10
Base Units
0Most common base units used in the metric system0 Gram (g)0 Meter (m)0 Liter (L)0 Second (s)0 Celsius degree (°C)
0All other units in metric system derived from these base units
Prefixes
0Kilo (x1000) [k]0Hecto (x100) [h]0Deka (x10) [D]0BASE UNITS (x1)0Deci (x0.1) [d]0Centi (x0.01) [c]0Milli (x0.001) [m]
Now make a mnemonic device for the metric
prefixes using the letters in red
Putting it all together…
0Kilosecond (ks = 1000 seconds)0Hectometer 0Centigram 0Dekasecond 0Deciliter 0Kilometer 0Milligram
(hm = 100 meters)
(cg = .01 gram)
(Ds = 10 seconds)
(dL = .1 liter)(km = 1000 meters)
(mg = .001 gram)
“m”
How can we tell whether an “m” stands for a meter or milli-?
0M at the end = meter0M at the beginning = milli0M by itself = meter
Practice
0400 millimeters in meters0 k h D (b) d c m0 4 0 00 =0.4 meters
05.27 kilograms in grams0k h D (b) d c m0 5.2 70 =5,270 grams
k h D (base) d c m
Practice
0Using your BYOT or iPads go to https://todaysmeet.com/andreskefsn
0Type your first & last name (no spaces) for the “nickname”
0Your message should include answers to the following:
1. 6.82 Dekaliters in deciliters2. 175 millimeters in hectometers3. 4 kilograms in centigrams
k h D (base) d c m
The Big Five1. Gram (g)- measurement of mass0Mass: a measure of the quantity of matter0Often confused with weight: the measure of force of
gravity between two objects0Equipment to measure mass
0 Triple beam balance0 Electronic balance
0Calibrate: adjust a measuring instrument to a standard0Tare: mass of the container, which is subtracted from the total
mass of the container and substance to find the mass of just the substance
Now it’s your turn…
0Complete “Balancing Chewing Gum” Experiment
The Big Five
2. Meter (m)- measurement of length0Length: the distance between two points0Equipment to measure length
0 ruler0 What if the object you need to measure is a potato?
3. Liter (L)- measurement of volume0Volume: the amount of space occupied by an object0Usually measure liquids by their volume0Be careful when measuring the meniscus: curve at the
surface of a liquid
The Big Five
Equipment to Measure Volume
Beaker: deep, wide-mouthed container with a pouring lip
Erlenmeyer flask: flat-bottomed, cone-shaped container
Graduated cylinder: tall container used to accurately measure the volume of liquids to the nearest milliliter
Buret: graduated glass tube with a control valve at the bottom
The Big Five
4. Second (s)- measurement of time0Critical to have someone act as a timer during
experiments0Record start and stop times using a clock/watch0Failure to accurately monitor time can make your
entire experiment invalid
5. Celsius degree (°C): is most commonly used unit of temperature0 Water freezes at 0°C0 Water boils at 100°C
0Temperature: a measure of heat intensity0The US still uses Fahrenheit scale for everyday
temperature measurements
The Big Five
Lab Experiment:
0 “Measuring the Volume of Irregularly Shaped Objects”0 How do you measure the volume of a biscuit?
0Once completed with the lab..0 Work on “Metric Units” worksheet
Scientific MethodAn organized approach to solving problems
1. ASK QUESTIONS2. DEFINE THE PROBLEM3. CONDUCT RESEARCH4. STATE THE HYPOTHESIS5. DESIGN THE EXPERIMENT6. CONDUCT THE EXPERIMENT7. EVALUATE THE RESULTS8. REPORT THE RESULTS
Steps in the Scientific Method1. ASK QUESTIONS
0 Why are you interested?0 What are the benefits of investigating this topic?0 How can this be analyzed?
0 For example, the Best Bean Company’s navy bean crop was destroyed by plant disease this year.0 Is there a substitute for navy beans that will be comparable
in flavor, texture, color, and cost?
Steps in the Scientific Method2. DEFINE THE PROBLEM
0 What is the exact purpose of your specific experiment?0 In class, problem = purpose for experiment0 Ex: To find a substitute bean similar in color, shape,
texture, flavor, cooking characteristics, and cost, as well as its’ impact of customer approval
Steps in the Scientific Method3. CONDUCT RESEARCH
0 List possible causes of your problem0 Books, articles, online sources
0Referred to as “Review of Literature”0 Check information on related studies0 Ex: finding names and descriptions of different kinds of
beans or looks for recipes using other types of beans
Steps in the Scientific Method
4. STATE THE HYPOTHESIS0 Hypothesis:
0A possible solution to the problem0an educated guess or prediction0An “if, then” statement
0 Ex: Greater northern beans, pink beans, and pinto beans are acceptable substitutes of navy beans.
Steps in the Scientific Method
5. DESIGN THE EXPERIMENT0 Variables:
0 Factor that is being changed0 Ex: kind of bean
0 Control:0 Standard against which you measure all changes0 Ex: navy bean
0 Variation:0 Change you made in the experiment0 3 variations (greater northern, pink, and pinto beans)
TYPES OF VARIABLES
0 Independent Variable0 The variable that is changed by the scientists0 The “I control” variable
0Dependent Variable0 The variable that might change because of what the
scientist changes0 What is being measured
Remember!
Your hypothesis can TELL you what your variables are!
Example: If I drink Mountain Dew before bed, then I will not sleep very much.
0 IV: Drinking Mountain Dew0 DV: the amount of sleep
Practice
Use this hypothesis to identify the variables:
If I consume a large amount of sodium, then my body will dehydrate more quickly.
0 IV:___________________________________________0 DV:__________________________________________
Practice
Use this hypothesis to identify the variables:
If I brush my teeth more, then there will be less plaque build-up on my teeth.
0 IV:___________________________________________0 DV:__________________________________________
Practice
Now read the experiment and identify the variables:
Elizabeth wanted to test if temperature affected how fast milk goes bad and curdles. She left milk in a room temperature closet, a fridge, and an oven that was turned on low heat. She then measured how rotten the milk was after 10 days.
0 IV:___________________________________________0 DV:__________________________________________
Going back to your hypothesis..
0Hypothesis: an educated guess or prediction; an “if, then” statement
If _____independent variable _____then _____dependent variable_____
Example:
Independent Variable:I feed my cat a lot of food
Dependent Variable:her weight will increase
If ______________________________then ______________________________
Remember!
Try to use INCREASE and DECREASE in your hypothesis!
Example: IF I increase the amount of water I drink, THEN I will increase the efficiency of my kidneys.
Steps in the Scientific Method
6. CONDUCT THE EXPERIMENT0 In class, groups will often conduct different variations
SO…..0 Follow experiment directions EXACTLY in order to
ensure accurate data
Steps in the Scientific Method
DATA COLLECTION0Numerical Observations:
0 i.e. Quantitative Observations0 Still require units and descriptions or the numbers
won’t make sense (time, temperature, mass, etc)0Descriptive Observations:
0 i.e. Qualitative Observations0 Factors such as color, texture, temperature, and odor
Steps in the Scientific Method
7. EVALUATE THE RESULTS0 Read data, observations, and notes0 Look for patterns, common factors, changes, and
questions0 Look for answers to the questions and support
for/against your hypothesis
Steps in the Scientific Method
8. REPORT THE RESULTS0 Form a CONCLUSION that analyzes and applies data0 Answers how, what, where, when, or why0 Many experiments may lead you to more than one
conclusions OR more than one option to solve your problem0State ideas for further research
0 Lab reports
Now try it on your own!
0Complete worksheet “A Variable Way to Practice Variables”
Assignment: The Twinkie Project
0Using the steps of the scientific method, create a hypothesis about Twinkies