Scientific Method and Standards of Measurement

• SCIENCE is a method of studying the natural world. It is a process that uses OBSERVATION and INVESTIGATION to gain knowledge about natural events.

• Life science (biology, microbiology, etc.) studies living things.

Earth science (geology,

meteorology, etc.) investigates Earth

and space.

Physical science (chemistry, physics, etc.) is the study of matter

and energy.

The Scientific Method

• is an organized set of procedures for investigating problems. (While scientists do not always follow a rigid set of steps, most investigations will follow this general pattern.)

• Notice how the steps always lead back towards the beginning. This is due to the fact that science is a continuous process.

• Following the process leads to a better understanding of the world we live in.

A hypothesis is an educated guess as to a solution to a problem.

It is untested.• A hypothesis should be 3 things: • TESTABLE (you can test it, it’s not totally

crazy; “Aliens exist.”)• FACT BASED (not an opinion; “Blue is the

best color.”)• a COMPLETE SENTENCE (not just a

number! “36”)

Once a hypothesis has been proven true through many

experiments, it can be termed a THEORY.

• A THEORY is an explanation of things or events based on many observations and investigations. It explains WHY something happens.

A SCIENTIFIC LAW is a statement about WHAT will happen under

certain conditions. It can often be explained mathematically.

• Example : the law of gravity

During an experiment, variables are tested. A VARIABLE is anything

that can be changed (or varied) in an experiment. There are many

parts to an experiment and variables.

• Independent Variable—the one you change or control to see how it will affect the other variables

• Dependent Variable—the one that changes in response to changes in the independent variable

• Constant—a variable you don’t change• Control—a standard to which results can

be compared.

• Example—if I want to see how Miracle Grow affects plant growth, I will give it to 4 plants. One gets ½ a spoonful per week, one gets 1 spoon, one gets 2 spoons, and the last one gets none at all. I give them all the same amount of sun and water.

• My INDEPENDENT VARIABLE is the amount of Miracle Grow, because I changed it to see what effect it would have. My DEPENDENT VARIABLE is plant growth, because it depends on how much Miracle Grow the plant got. Water and sun are CONSTANTS because I didn’t change them (I didn’t want them to affect my results). The CONTROL is the one with no Miracle Grow; I compare the growth of the other plants to this one.

STANDARDS OF MEASUREMENT

• Measuring is an important skill, especially in the field of science. However, in order to be useful, they must be standardized.

• Standard of measurement an exact quantity that people agree to use as basis of comparison.

• All measurements are compared to the standard. This way all measurements can be compared to each other.

INTERNATIONAL SYSTEM OF UNITS

• Otherwise known as SI, we call it the metric system.• These are accepted across the world as the standard:

Prefix Symbol Multiplying Factorkilo k 1000hecto h 100deka dk 10base 1deci d 0.1centi c 0.01milli m 0.001

• Kevin Has Diarrhea but Don’t Call Mom• King Henry Died by Drinking Chocolate Milk

Converting metrics

SI Base Units

Quantity Measured Unit Symbollength meter mmass gram gtime second selectric current ampere Atemperature Kelvin Kamount of substance mole molintensity of light candela cd

Vocabulary

• volume the amount of space occupied by an object

• mass the amount of matter in an object• density the mass per volume of a

material