Intro to Science and the Scientific Method

What is Science?

• Science is a process for inquisitive minds.
• Science helps solve problems.
• Science helps understand the world and find answers to interesting questions.

The Scientific Method

• The scientific method involves identifying a problem.
• Prediction/Hypothesis: Forming educated guesses based on the problem.
• Identify needed materials.
• Design an experiment.
• Gather evidence/data.
• Perform analysis on your data.
• Draw an evaluation.
• The evaluation may lead to new problems.

The Scientific Process

• Experiments begin with a problem.
• A hypothesis is formed after the problem has been defined clearly.
• An experimental design is created to test the hypothesis.
• Data is collected during the experiment.
• Data undergoes analysis.
• A conclusion is made through evaluation of the data and analysis.

Step 1: Title

• The title of a lab should be descriptive and relevant to the experiment.

Step 2: Problem

• The problem must be clearly stated.
• When appropriate, the problem should be stated in terms of manipulated (independent) and responding (dependent) variables.

Rules of Experimentation

• An experiment must have two parts for comparison: Parts A and B.
• Part A: Experimental Group contains the manipulated variable.
• Part B: Control Group does not have the manipulated variable and serves as a comparison for the experimental group.
• A minimum of 3 controlled variables are required and must be the same for each group.
• It is crucial to maintain only one variable to be the only difference between the experimental and control groups.
• Manipulated (independent) variable: the difference between two groups and usually appears on the x-axis.
• Fixing or controlling variables means keeping all the conditions identical for both groups.
• Responding (dependent) variable: the observed difference between the two groups and usually appears on the y-axis.
• A large number of trials is required.
• The experiment must be repeatable by other individuals with the necessary skills.
• The conclusion's scope must align with the experimental materials.

Experiment Example 1

• Test the effect of different size soccer balls when juggling.
• Manipulated Variable: The size of the soccer ball
• Responding Variable: The number of seconds the ball stays in the air.
• Controlled Variables: Who is juggling, the timer, where the juggling is performed.

Experiment Example 2

• The effect of sleep on aggression is studied by a researcher via the creation of 3 study groups consisting of 100 people.
• 25 people sleep 6 hours per night.
• 25 people sleep 3 hours per night.
• 50 people sleep as much as they need.
• Then you monitor any aggressive behavior during basketball games among the participants.
• Experimental groups: 6 hours per night, 3 hours per night.
• Control group: Sleep as much as they need.
• Manipulated variable: # of hours
• Responding variable: Aggressive behavior during basketball games.

Step 3: Background Information

• Background information is needed before beginning the experiment.
• Scientists utilize background information to remain on the right track and prevent duplicating work that has already been done.
• Background information is necessary to formulate a hypothesis.
• Example problem: "What effect does the number of chloroplasts in a plant cell have on the amount of starch produced by photosynthesis?"
• Requires knowledge of chloroplasts, starch, and photosynthesis.

Hypothesis

• Hypothesis: the expected answer to the problem based on a scientific concept.
• A hypothesis should directly answer the research question by proposing a relationship between the manipulated and responding variables.
• Provide reasoning or explain for the answer according to a scientific concept.
• Each hypothesis must be testable.

Step 5: Materials & Equipment

• All necessary lab materials and equipment should be listed in columns.
• Include data about sizes and quantities.
• Example: lab apron, stop watch, safety glasses, zinc metal, graduated cylinders, base solution etc.

Step 6: Procedure

• It is essential to implement a step-by-step approach to document how to complete experiment.
• Each step must be very specific and easy to follow.
• No textbooks should be utilized in lab environment.
• Steps should be numbered as a list in the correct order using complete sentences.
• Select proper intervals for the manipulated (independent) variable.
• Provide an appropriate amount of trials to ensure reliability.
• Include instructions for waste disposal, safe handling, and the need for personal protection clothing (lab apron/safety goggles).

Step 7: Evidence (Data Collection)

• Evidence includes all observations relevant to proving or disproving the hypothesis or answering the problem.

Types of Data

• Qualitative data: observations using unaided senses (color, hotter, colder, etc.)
• Quantitative data: involves actual measurements (mass or height of a plant, number of legs on an insect, etc.)

Validity vs Reliability

• Validity: Does the test measure what it is supposed to measure?
• Reliability: Is the test consistent and does it give the same results over and over?

Observations

• Sampling and measuring instruments must be used with skill and precision.
• The experimenter must be familiar with the procedures.
• Follow proper laboratory techniques, and keep techniques consistent, eliminate improper results from using dirty glassware.
• Data must be collected and recorded following Workplace Hazardous Information System (WHMIS).

Step 8: Data Table

• Data table must be constructed prior to starting the procedure in the laboratory.
• Titles, labels, and units need to be utilized.
• Independent (manipulated) variables are placed in the horizontal column.
• Dependent (responding) variable represent the data to be collected and is recorded in the vertical columns during the procedure.

Data Analysis

• Data must be manipulated, transformed, and presented in a form suitable for evaluation.
• Analysis of data includes: graphs, tables, and labeled drawings.

Graphing

• Data is represented visually in graphs.
• Two main types of graphs: line graphs and bar graphs.
• Line graphs: are often used with time is the manipulated variable.
• Bar graphs: can be used to show the amount of various parameters in a study.

Step 9: Evaluation

• Experiment results are reviewed when developing a valid conclusion based on the correct interpretation of the results, which includes providing adequate explanations for results.

Basic Skills

• To write a number to scientific notation:
• Move the decimal point until it is behind the first non-zero number.
• Count how many times you had to move the decimal point to do this.
• Multiply the number by the appropriate power
• Use a positive exponent if you moved the decimal to the left.
• Use a negative exponent if you moved the decimal to the right.

Types of Fields

• Gravitational Fields
• Electric Fields
• Magnetic Fields

Fields

• Fields have "spheres of influence", which can be measured for their affect on other substances
• Large, powerful nations can have an influence on nearby countries, and the influence decreases with distance.

Electric Fields A

• Electric charge is surrounded by an electric field, which is usually undetectable, but observable based on it's effects.
• Examples of observable effects: Lightning
• An electric field is the influence the electric charge as on the space around it.
• Utilize + and - charges to express positive and negative electric charges.
• Test body: An object that experiences a force because of a field, and then responds in an observable way.
• Insulator: A material that lacks the possibility of free-moving electrons.

Magnet Fields B

• Utilize compass for measurement.
• Another test body utilizing second type of invisible field.
• The compass's needle will spin when subject to surrounding magnetic field.

Properties of Magnets

• Every magnet has 2 poles (north and south)
• Like poles repeal.
• Opposite poles attract each other.

Gravitational Fields C

• The Earth’s gravitational field exerts a force on any mass within its field.
• Mass of gravitational source.
• Field strength increases as you travel toward the center of the Earth, and weakens as you move away.
• At sea level, the value for 'g' (gravitational force) in the gravitational field is about 9.81 m/s2, but decreases with altitude.
• Moon and Sun have gravitational fields.
• Very massive create gravitational field large enough to be observable.

Drawing Field Lines of a diagram

• Describes the direction and strength of the field.
• For gravity, the field lines point toward the centre of the Earth.
• The arrow of the field line direction always point in a specific directions
• The density of the lines indicates strength.

Drawing field lines for gravitational fields

• Shows the directions and densities.
• The earth creates attraction with gravity in each direction.

Drawing field lines for magnetic fields

• Magnetic field lines always
• Leave the north end of the magnet
• Enter the south end.
• forms a "loop" around the magnet.
• Magnetic field lines are both attractive and repulsive

Gravitational Field Strength (A)

Gravitational field strength refers to the force exerted by gravity on each kg of an object at a known location.

• Value is often represented as "g"= N/ky. This force is affected by the object's mass and distance from Earth's core
• Calculate gravitational field strength using the equation g = Gm / r^2, where:
  • "g" is gravitational field strength (N/kg)
  • "G" is the gravitational constant (6.67 x 10^-11 N m^2 / kg^2)
  • "m" is the mass of the gravitational field source (kg)
  • "r" is the distance from the center of the gravitational field source (m)
• Be very careful about distance measurement from the center of the object.

Earth Example

• Radius= 6.37x10 to the 6th m

• Mass= 5.98x10 to the 24th kg

• g= 9.83 (m/kg)

• Notice two units of measure are about equal -gravitational field strength = Acceleration due to Gravity -N \ kg = m \ s^2 Distance and gravity are inverse of one another