Transcript C2 PPT - lafayette co c-1

Chapter 2
Scientific Evaluation:
Being Objective
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Objectives
• Describe the role of science in new food
products.
• Identify the function of measuring
equipment.
• Demonstrate proper measurement
techniques.
• List steps of the scientific method.
• Use safety procedures in the lab.
continued
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Science in the Food Industry
• Scientific study in any field requires
– unbiased observation
– accurate measurement
– organized documenting of results
• To be scientific, an experiment must be
replicable, or repeatable
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Measurements
• Successful measuring requires you to
– identify what standard is being used
(International System of Units)
– determine what you want to measure
– decide what method of measurement & specify
the unit
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Measuring Mass and Length
• Mass measures the quantity of matter
– The metric unit is a gram (g)
– A kilogram (kg) is the mass of 1 liter of
water at 4 C
• Weight measures force of gravity between
2 objects
• Length is the distance between 2 points
– Metric unit for measuring length is meter (m)
– Measured with ruler
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Measuring Volume
• Volume is amount of space occupied by an
object
– Metric unit for measuring fluid volume is liter (L)
• Equipment used to measure liquids
– beaker—a wide mouthed container w/ pouring lip
– Erlenmeyer flask—cone-shaped container w/flat
bottom
– graduated cylinder—tall, thin container w/
pouring lip
– buret—a graduated glass tube
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How to Measure Volume
• Container on a flat surface
• Readings at eye level
• In narrow containers read from bottom of
curve at liquid’s surface, the meniscus
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Measuring Time
• Measured in seconds
• Appoint someone as timer
• Failure makes experiment invalid
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Measuring Temperature
• A measure of heat intensity
• Celsius degree is 0.01 of the difference
between the boiling and freezing points of
water
– Water boils at 100 C
– Water freezes at 0 C
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The Scientific Method
• A system of steps used to solve problems
• Ask questions
– Ask what, why, and how of a problem
• Define the problem
– Clarify question, set goals
continued
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The Scientific Method
• Conduct research
– List possible causes of problem
– Gather as much info as possible
• State hypothesis, or possible solution
– A hypothesis repeatedly tested over a variety
of conditions becomes a theory
– Laws are theories widely accepted
continued
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The Scientific Method
• Design the experiment
– Make it answer questions such as how to test
the hypothesis, what equipment will be used,
how to collect and record the data, and what
safety precautions need to be taken
– A well-designed experiment will have a
variable and a control
– Each change in an experiment is a variation
continued
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The Scientific Method
• Conduct the experiment
– Follow procedures exactly and measure
accurately
– Records of observations will be numerical or
descriptive
– Record data appropriately and neatly
continued
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The Scientific Method
• Evaluate results
– Reflect
– Look for patterns, common factors, changes,
and questions
– Look for answers to the questions and whether
they provide support for or against the
hypothesis
• Report the results
– A conclusion analyzes and applies data
– Experiments may lead to more than one
continued
conclusion and reveal need for further research
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Evaluating Scientific Studies
• A process of discovery and debate
• Medical experts may be involved to evaluate
• 2010 update of the Dietary Guidelines for
Americans, recommends consuming more
nutrient-dense foods
• Conflicting reports may exist
• Researchers often examine hundreds of
studies before making recommendations
• A meta-analysis gives overall conclusions to
continued
multiple studies of the same issue
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Lab Safety
• General guidelines
– Follow lab rules and
procedures
– Avoid horseplay
– Keep hair back
– Be cautious around heated
glass
– Protect eyes and skin
– Mix chemicals as instructed
– Plan time for cleanup
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continued
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Recap
• Food scientists develop new food
products and better methods of
preserving and preparing food through
experimentation
• Using proper measuring equipment and
techniques are crucial during food
science experiments
• Avoid accidents by following all lab
safety procedures at all times
continued
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Recap
• The steps of the scientific method are to
– ask questions
– define the problem
– conduct research
– state the hypothesis
– design the experiment
– conduct the experiment
– evaluate the results
– report the results
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