EARTH SCIENCE Scientific Method

The world is full of problems!

Scientific Method A set of procedures a scientist would follow in solving a problem!

1. Define the Problem

2. Collect Data on the Problem

What is Data? Information from which conclusions can be made.

Scientific Method 3. Draw a Hypothesis

What is a Hypothesis An Educated Guess!

Scientific Method Choose ALL of the statements below that are stated as a hypothesis. Baking powder is used in biscuits. The brighter the color of an orange, the juicier the fruit. Brass contains copper and zinc. Most apples are red, but some are yellow. The faster a river flows, the greater the erosion.

Some chickens lay an egg every day. Other chickens produce few eggs. A study is planned to examine factors that might affect the number of eggs produced by chickens. Which of the following is NOT a suitable hypothesis for the study?

If chickens receive more hours of light, then they will produce more eggs. If more eggs are produced by chickens, then they lose more weight. If the cage for chickens is larger, then they will produce more eggs. If there is more protein in the feed, then more eggs are produced.

4. Plan & Perform an Experiment

For an Experiment to be VALID, it needs A Control Group A Test Group

Students in a science class placed ice cubes in a cup. They were studying variables that affected how long it takes the ice to melt.

Select the variable that would most likely NOT affect the time it takes the ice to melt. Size of cup Number of students Size of ice cube Temperature of the room

Example A student pours 100 mL of hot water carefully into one beaker and pours 100 mL of cold water into another beaker. He drops a lump of sugar into each beaker and times how long it will take each sugar cube to dissolve. Will this experiment show the effect water temperature has on the rate at which sugar dissolves? To be VALID, there can only be 1 VARIABLE!

A student pours 100 mL of hot water carefully into one beaker and pours 100 mL of cold water into another beaker. He drops a lump of sugar into each beaker and times how long it will take each sugar cube to dissolve. Will this experiment show the effect water temperature has on the rate at which sugar dissolves?

Example A scientist designs an experiment to see if plants need sunshine to grow. Twenty four growing plants are placed in a dark closet. Two weeks later, all the plants are dead. Does this experiment prove that plants need sunshine? To be VALID, there can only be 1 VARIABLE!

Scientific Method There are 2 types of Variables? Dependent Variable Independent Variable

Scientific Method Dependent Variable What you measure in an experiment. What is being affected during an experiment.

Scientific Method A group of identical plants are grown with different nitrogen levels.

What is the dependent variable? Plant Height Nitrogen Level

Scientific Method Independent Variable This is what is changed to test a hypothesis. What is causing the affect during an experiment.

Scientific Method A group of identical plants are grown with different colors of light.

What is the Independent Variable? Color of Light Plant Height

What is the Independent Variable in this experiment?

Scientific Method Independent Variable = Soil Type

5. Collect & Record Your Observations

Measurements Qualitative Non-Numerical Can be observed but not measured!

Quanitative Numerical Can be observed and measured!

Qualitative or Quantitative? Mass Size pH Color Salt deposits form.

Accuracy & Precision Accuracy refers to the closeness of measurements to the correct or accepted value of the quantity measured.

Precision refers to the closeness of a set of measurements of the same quantity made in the same way.

Accurate &/or Precise?

Power of the Graph! ChartGraph Organizes Data ☺ ☺ Displays Data ☺ ☺ Predicts Data ☺

Scientific Method 6. Draw a Conclusion

Scientific Theory Represents a hypotheses, or a group of related hypotheses, which has been confirmed through repeated experimental tests.

Scientific Method A student decides to set up an experiment to see if cats preferred skim milk or 2%milk. She put out a cup of milk and a cup of 2%milk. Both milks were served at the same temperature. She then measured which type and how much milk her 5 kittens drank over the course of a day. The student discovered that the cats liked the 2% more than the skim milk. What is wrong with the above experiment?

7. Communicate Your Findings