Tools, Meas, Safety Ch1.4 7th

CHAPTER 1 SECTION 4

Tools, Measurement, and Safety

Objectives

Provide 3 examples for how scientists use computers and technology

Describe 3 tools that scientists use to observe organisms

Explain the importance of the International System of Units (provide 4 examples)

Computers

Technology: application of science for practical purposes

1st electronic computer was built in 1946

Computers can create graphs, solve complex equations, analyze data

Help scientists share ideas, publish reports

Tools for Seeing

Compound Light Microscopes Magnifies small objects to be seen easily 3 main parts: tube with lenses, stage, light

Transmission Electron Microscope (TEM) Use electrons to produce magnified images Electrons pass through the specimen to produce a flat

image

Scanning Electron Microscope (SEM) Electrons bounce off of the surface of the specimen to

produce a 3-D image

Measurement

International System of Units (SI Units)

Developed in the late 1700’s

All units based on the number 10

Conversions are easier

Length

SI Unit is the meter

Conversions: Kilometer (km): 1km = 1,000m Decimeter (dm): 1 dm = 0.1m Centimeter (cm): 1cm = 0.01m Millimeter (mm): 1mm = 0.001m Micrometer (μm): 1µm = 0.000001m Nanometer (nm): 1nm = 0.000000001m

Area

A measure of the size of a surface or region

Calculated using units of length and width

Stated in square units (m²), (cm²), (km²)

Volume

The measure of the size of something in 3-D space

Most often described in liters (L)

Liters are based on the meter

One cubic meter: 1m³ = 1,000L

One cubic centimeter: 1cm³ = 1mL

Mass

The measure of the amount of matter in an object

Basic SI unit of mass is the kilogram (kg)

Very large objects are measured in metric tons = 1,000kg

Temperature

How hot or cold something is

The amount of energy within matter

Commonly measured in: Fahrenheit (ºF) Celsius (ºC)

SI unit of temperature is the Kelvin (K) – notice no degree symbol!

Temperature comparisons

212 ºF and 100ºC – water boils

32ºF and 0ºC – water freezes

98.6ºF and 37ºC – normal body temperature

Kelvin???

Quick Quiz

What is the SI unit for length, mass, and temperature?

What is the area of a compact disc case with sides measuring 14cm and 12.5cm?