Life Science

Ch 1 the World of Science

Objectives sec 1

• Explain the importance of asking questions in science.

• State examples of life science at work.

• List three ways life science is beneficial to living things.

A. It all starts with a question

1. Life Science is the study of living things.

2. In your Own Backyard You can ask questions about familiar organisms.

3. Touring the World The questions you ask about your neighborhood are just a sample of all the questions you could ask about the world.

B. Life Scientists

1. Anyone Women and Men from any cultural background can become life scientists.

2. Anywhere Life scientists carry out investigations in laboratories, on farms, in forests, on the ocean floor––even in space!

3. Anything Life scientists study any thing that is a live, or that used to be alive, that interests them.

C. Why ask questions?

1. Fighting Diseases Science has led to many life-saving discoveries, such as the vaccination for polio

2. Understanding Inherited Diseases By learning about how some diseases are inherited and how they affect people, scientists hope to find ways to prevent or cure these diseases.

3. Protecting the Environment Understanding how we affect the world around us is the first step in finding solutions to problems such as pollution and the extinction of wildlife.

II Scientific MethodsA. What are they?

1. Scientific methods are the ways in which scientists answer questions and solve problems.

B. Ask a question1. 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?”

2. Accurate Observations Any information that you gather through your senses is an observation. – Scientist use standard tools and methods to make

and record observations.

C. Form a Hypothesis1. Hypothesis =possible explanation or answer to a

question that is based on observation and can be tested.

2. Prediction= A statement of cause and effect that can be used to set up a test for a hypothesis

D. Test your hypothesis1. Under Control A controlled experiment tests only one

factor at a time and consists of a control group and one or more experimental groups.

2. Designing an Experiment Designing a good experiment requires planning and a consideration of all factors.

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

E. Analyze the results

1. After they finish their tests, scientists must analyze the results– Analyzing the results helps

scientists explain and focus on the effect of the variable.

F. Draw Conclusions

1. Scientists must conclude if the results of their tests support the hypothesis.

2. Proving that a hypothesis is not true can be as valuable as proving that it is true.

G. Communicate results

1. After finishing an investigation, scientists communicate their results.

2. Sharing allows other scientists to repeat experiments to see if they get the same results.

3. Sometimes, new data lead scientists to change their hypotheses.

Objectives

1. Give examples of three types of models.

2. Identify the benefits and limitations of models.

3. Compare the ways that scientists use hypotheses, theories, and laws.

III. Scientific modelsA. Types of Science Models

1. Physical Models Physical models, such as miniature volcanoes and steam engines, look like the thing that they model.

2. 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. 3. 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

B. Building Scientific knowledge1. Scientific Theories An explanation that ties

together many related observations, facts, and tested hypotheses is called a theory.

2. 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

3. Scientific Change If new evidence challenges an accepted idea, scientists must reexamine the old evidence and reevaluate the old idea.

Objectives

1. Give three examples of how life scientists use computers and technology.

2. Describe three tools life scientists use or observe organisms.

3. Explain the importance of the International System of Units, and give four examples of SI units.

IV. Tools, Measurement & SafetyA. Computer & technology

1. Technology = application of sciences for practical purposes

2. Computers are used to create graphs, solve complex equations, and analyze and communicate data.

B. Tools for seeing

1. Compound Light Microscope is an instrument that uses two or more lenses to magnify small organisms.

2. 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

C. Units of measurement1. 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

2. Length The basic unit of length in the SI is the meter– Km (kilometer= 1000 m)– cm (centimeter = 100 m)

3. Area The measure of how much surface an object has. Use the following equation:

area length width–Measured in m2, Km2 or cm2

3. 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

5. Mass A measure of the amount of matter in an object– Measured in grams (g) – 1000g = 1 ton

6. 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

Know these symbols from your book