Scientific method

Warm-up A student wants to test the effect of watering plants with different sorts of fluid (such as juice or soda). Write a hypothesis that would apply to this experiment.

PRAIRIE CARRYING A BONE Dogs and Turnips THE BIG FAT RED DOG WALKED INTO THE LITTLE WHITE HOUSE ON THE PRAIRIE CARRYING A BONE AND ATE HIS BOWL OF TURNIPS

Science is a Process

The Scientific Method Observations and questions Hypothesis Collecting data Interpreting results Disseminating findings Repeat!!!

Hypothesis A testable statement that can be proved or disproved through controlled experimentation. A null hypothesis is a statement that can be proved wrong. Example: Fish death has no relationship to contaminates in the water.

Writing a Hypothesis Must be logical Must be testable If, then statements* Written as a statement, not a question* (even if you are coming to the experiment looking for the answer to a question) Must include independent and dependent variables! *Most labs and real-world science use null hypothesis

Examples If you get at least 6 hours of sleep, you will do better on tests than if you get less sleep All daisies have the same number of petals The number of pets in a household is unrelated to the number of people living in it If you cover a wound with a bandage, then it will heal with less scarring A person's preference for a shirt is unrelated to its color. If you drink coffee before going to bed, then it will take longer to fall asleep.

Types of Variables Independent Dependent The thing you are testing in an experiment YOU control this Only one per experiment Dependent The change that happens because of the independent What you look for in an experiment Static / stabilizing / constant All the variables that stay the same

Remember! Your hypothesis tells you your variables! EX: If I drink coffee before bed will I sleep better? IV: DV: Drinking coffee Quality of sleep

If I leave all the lights on all day my electric bill will be expensive When I brush my cat more there is less fur on my furniture 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 a oven that was turned on low heat. She then measured how rotten the milk was after 10 days.

Control group Control: The part of the experiment that the scientist doesn’t change or add the variable to Establishes a base-line for comparison Ex. The plant with the water

Theory- a hypothesis that has been repeatedly tested and confirmed by multiple groups of researchers and is widely accepted. Natural Law- When a theory has been tested multiple times and there are no known exceptions. Ex. Law of gravity and laws of thermodynamics.

Controlled Experiments and Natural Experiments Controlled experiment- an experiment conducted in the controlled conditions of a laboratory. Natural experiments- when a natural event, such as a volcano, acts as an experimental treatment in an ecosystem.

Graphing! Line graph Bar graph Pie chart Used most often Used for showing change over time Generally represented of any change Can have multiple lines comparing change of two things Bar graph Comparing multiple sets of data Pie chart Parts of a whole percentages

Exit - Ticket Come up with an experiment. Write a hypothesis Identify the: IV DV ST Control group constant