Scientific Methodology

• One Goal of Science is to provide natural explanations for events in the natural world

• Then, use those explanations to understand patterns in nature and make predictions about natural events

1. Observations: the act of noticing and describing events in a careful, orderly way; * Uses the senses* Can be Qualitative (descriptions)

ie: The classroom floor is shiny

or

Quantitative (numbers)ie: There are 23 students in the classroom

- these observations lead to Questions or PROBLEMS which

need to be solved

2. Hypothesis: possible explanation for observations or questions that can be tested

Written as “if IV, then DV, because…”

3. Controlled Experiment (test) - only ONE variable is changed- control group: exposed to the same conditions as experimental group EXCEPT for one Independent Variable (IV)

4. Collect/ Record/ Analyze Data -

- Qualitative Data (descriptions) and Quantitative Data (numbers; measurements)

* Data can be collected and organized into a Data Table then represented

using Graphs

Table and graph titles:

The DV as a function of the IV

5. Conclusions - experimental data is used as Evidence to support, refute, or revise the hypothesis.

* Inferences - an explanation or interpretation of your observations or data.

- they SHOULD be reasonable or logical and based upon your data

For example, suppose you are on a photo safari in Africa. In a region bordering some small farms, you see some domestic cattle sharing space with some wild antelope. Some people in your group make the following observations and inferences.

Observation: The cattle and the antelope are standing quietly together.

• Inference 1: The cattle and antelope do not attack each other. • Inference 2: None of the animals in this region attack each other.

Observation: Some of the cattle are eating grass.• Inference 3: The grass is food for the cattle and antelope. • Inference 4: Most of the grass in this area is eaten by the cattle.

• Predicting - – Making an inference about a future event

based upon current evidence or past experience.

Look for patterns

Can turn out not to be true

Are usually tested

Identifying Variables

Every experiment involves several variables - factors which can

change

Independent Variables

• Also called “Manipulated variables” or IV

• This is the variable you PURPOSELY change and test

• ie - the temperature of the room

Dependent Variable

• Also called - “Responding Variable” or DV

• The factor that MAY CHANGE as a result of the Independent Variable

• ie: how fast plants grow in response to the temperature change.

Controlling Variables

• Keeping all conditions the same EXCEPT for the Independent Variable (IV)

• Ie: size of the container, type of soil, amount of water, amount of light, use of fertilizers, same kind of plants

• When all variables are controlled, you can then conclude that the differences in your results are due to the changes in the Independent Variable (IV)