SCIENCE

SCIENCE

The goal of science is to understand the world around us. This involves curiosity. Asking questions is a start:

The Goals of Science to investigate and understand nature to explain events in nature to use those explanations to make useful

predictions

Understanding Fossil Butte 50 million year old

fish found at the top of Fossil Butte in Wyoming

Pacific Ocean over 1000 km away

How did they get there???

Before starting an experiment you can form an inference. Inference is the ability to use the information you have already obtained to help you form a hypothesis.

For example: Guess what five items are in the shoebox. Use your senses.

Observation between you an your partner may vary. It can be unreliable.

For example: If there were a car accident with 10 witnesses, chances are not all will agree on what happened.

Do demonstration.

Observation Based on five senses: sight, hearing, taste,

smell, touch Quantitative – numerical

Ex- how many, how big, how fast Qualitative – descriptive

Ex – color, texture, smell, behavior

If an experiment is done enough times it may become worthy of becoming a theory. A theory is a powerful, time tested concept that make useful and predictable predictions about the natural world.

Example: The Big Bang Theory

A Theory in Science A very well supported hypothesis When a hypothesis has been verified many

times by different scientists, it becomes a theory

Redi’s, Spallanzani’s, and Pasteur’s experiments led to the theory of biogenesis (life comes from life)

Theories explain phenomena in nature

Spontaneous Generation In the past, people

thought life could just appear from non living matter

Ex – maggots just appear on meat

Redi’s Experiment 1668 – proposed hypothesis that the maggots came from flies

Tested hypothesis by placing meat in jars and covering some of the jars

Everything was controlled (kept the same) except the variable (covering jars)

Redi’s ExperimentUncovered jars Covered jars

Several days pass

Maggots appear No maggots appear

Types of Variables Independent: the variable being

manipulated Redi controlled the covering of the jars

Dependent: the variable that changes in response to the independent variable The presence of maggots in Redi’s

experiment

Spallanzani’s Experiment Tested Redi’s

results Boiled to kill

microorganisms What are the

independent and dependent variables??

Gravy is boiled.Flask isopen.

Gravy is teeming with microorganisms.

Gravy is boiled.

Flask issealed.

Gravy is free of microorganisms.

Pasteur's Experiment Provided final proof that

spontaneous generation did not occur

Broth is boiled. Broth is free ofmicroorganismsfor a year.

Curved neckis removed.

Broth is teeming with microorganisms.

Section 1-2

Figure 1-11 Pasteur’s Experiment

Go to Section:

Pasteur's Experiment

Pasteur's Experiment What was Pasteur’s hypothesis?

Microorganisms would not just appear Independent variable?

Curved neck of flask Dependent variable?

Presence of microorganisms

Scientific facts are known to absolutely true after hundreds of repetitive trials of an experiment.

Fact: The world is round.

Myths: legends that express basic beliefs(made up stories that may be believed)

There are sewer fairies in the sewers of Las Vegas.

EXAMPLE OF A LAB WRITE-UP

1. Define problem: Why do leaves change color?

2. Research: (Collect 5 sentences about the subject

being studied. These must be in complete sentences, in your own words, and from an outside source).

3. Hypothesis: (Form an educated guess)

Hypothesis (Form an educated guess) Logical, testable, tentative explanation for

a set of observations or a possible answer to a scientific question

Arise from prior knowledge, logical inferences, or imaginative guesses

Testing hypotheses Can be done through further observation Usually done through controlled

experiments A hypothesis proven to be wrong still adds

to the body of scientific knowledge

4. Experiment: (Also known as the procedure) a. Place four different trees into four separate

environments. 1. Cold with daily decreasing light. 2. Room temperature with uniform light

from day to day. 3. Cold with uniform light. 4. Room temperature with daily decreasing

light.

Types of Variables Independent: the variable being

manipulated

Dependent: the variable that changes in response to the independent variable

Variables: LIGHT TEMPERATURE (Those factors actually causing there to be

change)

Experimental setup: The part that will actually change. In this case the tree that loses color in its leaves.

Control setup: The part that does not do any changing at all because it is present to use as a comparison of what is “normal”.

5. Results: Data recorded on a graph(collection of info from lab)

0

20

40

60

80

100

120

week 1 week 2 week 3 week 4

cold/dec.rm tem/unicold/unirm temp/dec

6. Conclusion: (Explain results). Temperature alone does not determine

how many leaves don’t stay green. Decreasing day light also affected the variables.

https://glacier.qc.maricopa.edu/biology/scientific_method/index.cfm

This will take you through the steps of the scientific method, set by step.

List of Equipment:A. Hand lens or magnifying glass

B. Dissecting pan

C. Dissecting pins

D. Forceps (tweezers)

E. Dissecting scissors

F. Probe

G. scalpel

H. Safety goggles

I. Triple beam balance

J. Graduated cylinder

K. Test tube

L. Beaker

M. Test tube holder

N. Bunsen burner

O. Medicine dropper

P. Pipette

Q. Microscope

R. Glass slide

S. Cover slip

T. Petri dish

U. Thermometer

V. Funnel

W. Metric ruler