science basics. there are two types of observations: quantitative observations involve measurements...

Science Basics

There are two types of observations:  

• Quantitative observations involve measurements or estimates that yield meaningful, numerical results.

•  Qualitative observations yield descriptive, non-numerical results. 

Comparison of Qualitative and Quantitative Observations

Qualitative (words only)

Quantitative (words and numbers)

The girl has very little money. The girl has 85 cents.

The man is short. The man is 5 feet 2 inches tall.

Use a small test tube. Use a test tube that is 12 centimeters long.

It is a short walk to my house. It is about 1 mile to my house.

How do we measure?

• The metric system is an international decimal-based system of measurement. 

• Because the metric system is a decimal system, making conversions between different units of the metric system are always done with factors of ten.

King Henry Died Unusually Drinking Chocolate Milk

SI UnitsMeasurement Unit Symbol

Mass Gram g

Length Meter m

Time Second s

Temperature Kelvin K

Quantity Mole mol

Energy Joule J

Pressure Pascal Pa

Mass and weightWhat’s the difference?

• The mass of an object is a measure of the amount of matter in it.

• The basic unit of mass in the International System of Units is the kilogram.

• The weight of an object is the force of attraction between the object and the earth (or whatever large, gravity-producing body the object is located on).

No Calculator Vomit!!!

• In Science we use significant figures! • We like accuracy and precision!!

2732100000000000

Counting Significant FiguresAtlantic / Pacific Method     a. Absent Decimal- Start on “atlantic” side   of 

number & cross out all zeroes until 1st nonzero digit is reached, remaining digits are significant

    b. Present decimal- start on the “pacific” side of the number & cross out all zeros until the 1st nonzero digit Is reached, remaining digits are significant

How many significant figures are in each of the following measurements?

24 mL 2 significant figures

3001 g 4 significant figures

0.0320 m3 3 significant figures

6.400 x 104 molecules 4 significant figures

560 kg 2 significant figures

Scientific Notation• Move the decimal between the first and second significant figure.

• Count the number of “jumps” the decimal moved.• If decimal moves to the right, the exponent will be negative.

• (this is a small number)• If decimal moves to the left, the exponent will be positive.

• (this is a large number)

6352 6.352 x 103

0.00285 2.85 x 10-4

Density

Density Exploration• Go home this weekend and try layering some kitchen substances based on their density.

Graphing• Collect your data.• Determine the range of your data.

• Arrange data so you use the entire sheet of paper• Label your graph and your axes. 

• Title should be Y vs. X• Independent data: X; Dependent data: Y

• Plot your data.• Draw a "line of best fit.“

• Rarely will this be a connect-the-dots line• Think about what your graph means.

Graph Example