1. Life Science
Ch 1 the World of Science

2. II Scientific Methods A. What are they?
Scientific methods are the ways in which scientists answer questions and solve problems.
We use the scientific method to help preform an experiment
experiment= an organized procedure to study something under controlled conditions

3. B. Steps to a scientific investigation
Asking a question helps focus the purpose of the investigation
Scientists often ask a question after making an observation.
For example, students observing deformed frogs might ask, “Could something in the water be causing the deformities?”
Accurate Observations Any information that you gather through your senses is an observation.
Scientist use standard tools and methods to make and record observations.

4. C. Form a Hypothesis
Hypothesis =possible explanation or answer to a question that is based on observation and can be tested.
Prediction= A statement of cause and effect that can be used to set up a test for a hypothesis

5. D. Test your hypothesis
Controlled Experiment= tests only one factor at a time and consists of a control group and one or more experimental groups.

6. Variables= any factor that can change in an investigation
Designing an Experiment Designing a good experiment requires planning and a consideration of all factors
Variables= any factor that can change in an investigation
Independent variable= the factor that is deliberately changed in an investigation
Dependent variable= changes as a RESULT of changes to the independent variable
Control= part of the experiment that is identical to the experimental group except that the independent variable is not manipulated elephant
run in the rain

7. Collecting Data Scientists keep clear, accurate, honest records of their data so that other scientists can repeat the experiment and verify the results.

8. E. Analyze the results
After they finish their tests, scientists must analyze the results
Analyzing the results helps scientists explain and focus on the effect of the variable.

9. F. Draw Conclusions
Scientists must conclude if the results of their tests support the hypothesis.
Proving that a hypothesis is not true can be as valuable as proving that it is true.

10. G. Communicate results
After finishing an investigation, scientists communicate their results.
Sharing allows other scientists to repeat experiments to see if they get the same results.
Sometimes, new data lead scientists to change their hypotheses.

12. Objectives Give examples of three types of models.
Identify the benefits and limitations of models.
Compare the ways that scientists use hypotheses, theories, and laws.

13. III. Scientific models A. Types of Science Models
Physical Models Physical models, such as miniature volcanoes and steam engines, look like the thing that they model.
Mathematical Models A mathematical model may be made up of numbers, equations, and other forms of data.
Charts and graphs are examples of mathematical models.
Conceptual Models Conceptual models are systems of ideas or comparisons of unfamiliar things with familiar things to help explain unfamiliar ideas – the origin of life

14. B. Building Scientific knowledge
Scientific Theories An explanation that ties together many related observations, facts, and tested hypotheses is called a theory.
Scientific Laws A scientific law is a statement of what will happen in a specific situation
A law tells you how things work
Based on many proven hypothesis
Very few
Scientific Change If new evidence challenges an accepted idea, scientists must reexamine the old evidence and reevaluate the old idea.

15. Objectives
Give three examples of how life scientists use computers and technology.
Describe three tools life scientists use or observe organisms.
Explain the importance of the International System of Units, and give four examples of SI units.

16. IV. Tools, Measurement & Safety A. Computer & technology
Technology = application of sciences for practical purposes
Computers are used to create graphs, solve complex equations, and analyze and communicate data.

17. B. Tools for seeing
Compound Light Microscope is an instrument that uses two or more lenses to magnify small organisms.
Electron Microscopes focuses a beam of electrons to magnify objects.
produce clearer and more detailed images than light
cannot be used to observe living things

18. C. Units of measurement
The International System of Units= Begun by the French Academy of Sciences in the late 1700s
All SI units are based on the number 10, which makes conversion from one unit to another easy

19. Length The basic unit of length in the SI is the meter
Km (kilometer= 1000 m)
cm (centimeter = 100 m)
Area The measure of how much surface an object has. Use the following equation:
area  length  width
Measured in m2, Km2 or cm2
Volume The measure of the size of a body or region in three-dimensional space.
Measured in L or mL for liquids
Measured in cm3 or m3 for solids

20. Mass A measure of the amount of matter in an object
Measured in grams (g)
1000g = 1 ton
Temperature The measure of how hot (or cold) something is
Measured in degrees Celsius or Kelvin for science
212oF or 100oC water boils
32oF or 0oC water freezes
37oF or 98.6o C average body temp

21. Know these symbols from your book