Scientific Evaluation Being Objective

Measurements Taking accurate measurements is only one aspect of scientific experiments When recording measurements, be sure to list the units Important to indicate whether you measured in metric or English units

The Metric System How the world communicates the results of its experiments Decimal system of measurement All units divisible by 10

Base Units Most common base units used in the metric system Gram (g) Meter (m) Liter (L) Second (s) Celsius degree (°C) All other units in metric system derived from these base units

Prefixes Kilo (x1000) [k] Hecto (x100) [h] Deka (x10) [D] BASE UNITS (x1) Deci (x0.1) [d] Centi (x0.01) [c] Milli (x0.001) [m] Now make a mnemonic device for the metric prefixes using the letters in red

Putting it all together… Kilosecond  (ks = 1000 seconds) Hectometer  Centigram  Dekasecond  Deciliter  Kilometer  Milligram  (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-? M at the end = meter M at the beginning = milli M by itself = meter

Practice k h D (base) d c m 400 millimeters in meters k h D (b) d c m 4 0 0 =0.4 meters 5.27 kilograms in grams 5.2 7 =5,270 grams

Practice k h D (base) d c m Using your BYOT or iPads go to https://todaysmeet.com/andreskefsn Type your first & last name (no spaces) for the “nickname” Your message should include answers to the following: 6.82 Dekaliters in deciliters 175 millimeters in hectometers 4 kilograms in centigrams

The Big Five Gram (g)- measurement of mass Mass: a measure of the quantity of matter Often confused with weight: the measure of force of gravity between two objects Equipment to measure mass Triple beam balance Electronic balance Calibrate: adjust a measuring instrument to a standard Tare: 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… Complete “Balancing Chewing Gum” Experiment

The Big Five Meter (m)- measurement of length Length: the distance between two points Equipment to measure length ruler What if the object you need to measure is a potato?

The Big Five Liter (L)- measurement of volume Volume: the amount of space occupied by an object Usually measure liquids by their volume Be careful when measuring the meniscus: curve at the surface of a liquid

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 Second (s)- measurement of time Critical to have someone act as a timer during experiments Record start and stop times using a clock/watch Failure to accurately monitor time can make your entire experiment invalid

The Big Five Celsius degree (°C): is most commonly used unit of temperature Water freezes at 0°C Water boils at 100°C Temperature: a measure of heat intensity The US still uses Fahrenheit scale for everyday temperature measurements

Lab Experiment: “Measuring the Volume of Irregularly Shaped Objects” How do you measure the volume of a biscuit? Once completed with the lab.. Work on “Metric Units” worksheet

Scientific Method An organized approach to solving problems ASK QUESTIONS DEFINE THE PROBLEM CONDUCT RESEARCH STATE THE HYPOTHESIS DESIGN THE EXPERIMENT CONDUCT THE EXPERIMENT EVALUATE THE RESULTS REPORT THE RESULTS

Steps in the Scientific Method ASK QUESTIONS Why are you interested? What are the benefits of investigating this topic? How can this be analyzed? For example, the Best Bean Company’s navy bean crop was destroyed by plant disease this year. Is there a substitute for navy beans that will be comparable in flavor, texture, color, and cost?

Steps in the Scientific Method DEFINE THE PROBLEM What is the exact purpose of your specific experiment? In class, problem = purpose for experiment 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 Method CONDUCT RESEARCH List possible causes of your problem Books, articles, online sources Referred to as “Review of Literature” Check information on related studies Ex: finding names and descriptions of different kinds of beans or looks for recipes using other types of beans

Steps in the Scientific Method STATE THE HYPOTHESIS Hypothesis: A possible solution to the problem an educated guess or prediction An “if, then” statement Ex: Greater northern beans, pink beans, and pinto beans are acceptable substitutes of navy beans.

Steps in the Scientific Method DESIGN THE EXPERIMENT Variables: Factor that is being changed Ex: kind of bean Control: Standard against which you measure all changes Ex: navy bean Variation: Change you made in the experiment 3 variations (greater northern, pink, and pinto beans)

TYPES OF VARIABLES Independent Variable Dependent Variable The variable that is changed by the scientists The “I control” variable Dependent Variable The variable that might change because of what the scientist changes 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. IV: Drinking Mountain Dew DV: the amount of sleep

Use this hypothesis to identify the variables: Practice Use this hypothesis to identify the variables: If I consume a large amount of sodium, then my body will dehydrate more quickly. IV:___________________________________________ DV:__________________________________________

Use this hypothesis to identify the variables: 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. IV:___________________________________________ DV:__________________________________________

Now read the experiment and identify the variables: 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. IV:___________________________________________ DV:__________________________________________

Going back to your hypothesis.. Hypothesis: 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 CONDUCT THE EXPERIMENT In class, groups will often conduct different variations SO….. Follow experiment directions EXACTLY in order to ensure accurate data

Steps in the Scientific Method DATA COLLECTION Numerical Observations: i.e. Quantitative Observations Still require units and descriptions or the numbers won’t make sense (time, temperature, mass, etc) Descriptive Observations: i.e. Qualitative Observations Factors such as color, texture, temperature, and odor

Steps in the Scientific Method EVALUATE THE RESULTS Read data, observations, and notes Look for patterns, common factors, changes, and questions Look for answers to the questions and support for/against your hypothesis

Steps in the Scientific Method REPORT THE RESULTS Form a CONCLUSION that analyzes and applies data Answers how, what, where, when, or why Many experiments may lead you to more than one conclusions OR more than one option to solve your problem State ideas for further research Lab reports

Now try it on your own! Complete worksheet “A Variable Way to Practice Variables”

Assignment: The Twinkie Project Using the steps of the scientific method, create a hypothesis about Twinkies