Scientific Method/ Independent and Dependent variable

Scientific Method (in order)

1. Question: 2. Research: 3. Hypothesis: 4. Test: 5. Analysis: 6. Conclusions:

Law

: describes what happens in a given situation in nature

Theory

: explains how something happens in nature

Hypothesis

A scientific explanation that can be tested through experimentation or observation

Placebo

A substance that has no therapeutic effect, often used as a control in experiments

scientific theory

A well-tested and widely accepted explanation for a phenomenon

Double-blind study

An experiment in which neither the participant nor the researcher knows whether the participant has received the treatment or the placebo

Question:

Ask it

Conclusions:

Based upon the analysis and what it answers about the hypothesis

Hypothesis:

Formed to know what we will be testing

. Research:

Gather background information

Senario: Bacteria are grown in a petri dish. One side of the dish is sprayed with an antibiotic. After a week, the number of bacteria colonies are counted on each side

IV: Antibiotic DV: Number of colonies

Senario: A stapler is used to staple 100 papers, it jams 5 times during the trial. A different brand of stapler performs the same test; it jams 22 times.

IV: Brand of stapler DV: number of times it jams

Senario: Pillbugs are placed in a container where they have a choice of a wet or a dry environment. Researchers record how much time was spent on each side.

IV: Enviornment (wet or dry) DV: Time spent on each side

Senerio: A cow is given a growth hormone and then compared to another cow that was not given a growth hormone. Both cows were weighed at 2 years

IV: Growth hormone DV: Weight

Senario: An apple is cut into slices. Half of the slices are sprayed with lemon juice. All slices are stored in a sealed plastic bag. After 4 days, they are observed to see how brown they turned

IV: Lemon juice DV: Brown-ness of the apple

Senario: Cockroaches are exposed to a pesticide. After 3 hours, 95% of the insects are dead.

IV: Pesticides DV: Amount of dead cockroaches

Senario: The respiration rate of a goldfish is measured. The goldfish is then placed in cold water and the respiration rate is measured again

IV: Temperature of water DV: Respiration rate

Senerio: Two different cars are traveling at 60 mph. At a certain point, both cars slam on the brakes. The distance it takes for each car to stop is then measured.

IV: Type of car DV: time it took for the car to stop

Senario: Two plants are grown using the same light and pots. One plant is given water that has been microwaved and the other plant is given regular tap water. Their height is measured after 2 weeks.

IV: Type of water DV: height

Senario: the blood pressure of a soldier is measured while he is resting. The soldier is then exposed to a stressful environment and his blood pressure is measured again

IV: environment (resting or stressful) DV: Blood pressure

Senerio: Mosquito repellent is sprayed on one arm and the other arm is not sprayed. The number of mosquito bites is counted after 2 hours

IV: if the arm was sprayed with repellent or not. DV: number of mosquito bites

Senerio: One grape is placed in tap water and another grape is placed in salt water. The change in their mass is measured after a day.

IV: type of water DV: Mass of grapes

Analysis:

Organize and explain the data

Research Bias

Process during which the researcher influences the results, either knowingly or unknowingly

Observation

The act of noticing and describing events or processes in a careful, orderly way.

Test:

The experiment to test hypothesis

Example of IV DV

The type of soda - diet or regular - is the independent variable. The level of blood sugar that you measure is the dependent variable

Indipendent variable

The variable that is deliberately changed in an experiment

controlled experiment

experiment in which only one variable is changed

Control group

in an experiment, the group not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment

Biology

the scientific study of life

Dependant variable

the variable that relies/changes on the independant variable