The Process of Science

How does it work?

Mystery Tubes

How is what you did (with the mystery tubes) similar to what scientists do to study a topic?

– Think about the steps you took to construct your model and the scientific method

Mystery Tubes Freewrite

Why won’t I show you the inside of the mystery tube?

How does this represent what science is all about?

There is no such thing as "THE Scientific Method."

                                                                                                     

http://evolution.berkeley.edu/evolibrary/article/0_0_0/nature_05

A Scientific Method

Observation

Explanation

Test

AnalyzeCommunicate

Realistic Scientific Process

1. Observe2. Ask question3. Form hypothesis4. Test5. Repeat test6. Analyze results7. Form new hypothesis 8. Ask new question9. Test10. Analyze results11. Repeat test12. …

Goals of scientific process

Disprove hypotheses to weed out explanations

Find the best current explanation

There are two possible outcomes: If the result confirms the hypothesis, then you’ve made a measurement. If the result is contrary to the hypothesis, then you’ve made a discovery.

– Enrico Fermi

VARIABLES

INDEPENDENT what you purposefully change– What “I” changed…– Graphed on x-axis

DEPENDENT depends on what you change– What is being measured – to determine effect of independent

variable

– Graphed on the y-axis

CONTROL AND CONSTANTS

CONTROL what stays normal– What you will you’ll compare the independent variable

back to

CONSTANTS what is the same for all test subjects– Something that is done to both the independent

variable and the control

Identifying Variables and Controls

As a table, attempt #1 on tonight’s homework

Can you determine?

Independent variable – Floor wax

Dependent variable – # of scratches

Control – Tiles with no floor wax

Constants– Test section, time

Hypothesis vs. Theory

Hypothesis – Testable explanation for an observation

Theory– A well tested explanation based on evidence,

experiments, hypotheses, observations, etc.

Writing a hypothesis (If…then, because)

If (independent variable), then (dependent variable), because (reason why)

Examples:– IF Family Guy is on, THEN I will accomplish less

homework, because I will be distracted.

– IF a plant gets more sun, THEN the plant will grow taller, because it can photosynthesize more.

Putting It All Together

Sarah was interested in studying the effects of lack of sunlight on the height of plants. She took two identical trays and filled them with the same type of soil and planted the same type of seed in each. She then decided that she would keep one tray in a room that was completely dark and the other on the window ledge. She watered each with 50 mL of water a day.

Answers

Question– Does light affect the growth of plants?

Answers continued…

Independent Variable– Amount of light

Dependent Variable– Plant height

Control– Plant on window ledge

Constants– Amount of water, type of soil, type of seed, trays

Answers continued…

Hypothesis– If a plant is placed in the dark, then it will not grow

as tall as plant in normal sunlight, because it will not be able to photosynthesize.

Improvements?– More plants