Warm up Page: 583, 1. Weather observation are based on a variety

of measurements including: atmospheric __________,

_______, _____________, wind speed and precipitation.

• Pressure, humidity, temp.

Page: 583, 2. Most thermometers use one of two liquids

which are ________ or _________

• Mercury or alcohol

Page: 584. 3. What does the instrument called a

barometer measure?

Air pressure

Objective: S.W.B.A.T.

• Identify various weather instruments and explain

what aspect of weather each measures

• Explain the units each weather instrument uses

• Complete by reading questions on weather

instruments

Activities: • Warm-ups

• Notes/discussion

• Worksheet on weather instruments

Weather Weather Instruments

Chap 21, sec. 3

Meteorologist need data from a variety of

sources (tools and instruments) that help

predict weather.

Air Temperature Thermometer – use to measure air temp., made with a glass tube with either mercury(silver) or alcohol (red or green)

H20 =

Fahrenheit = 32˚ freezing

212˚ boiling

Celsius = 0˚ freezing

100˚ boiling

Air Moisture (humidity) Relative humidity – amount of water vapor in the air

compared to the greatest amount it can hold.

Measured in % (percent)

100% humidity air can not hold any more water vapor

(saturated)

The temperature at which air can become saturated

(and condenses) is called (dew point)

Psychrometer & Sling psychrometer – instrument that

uses two thermometers (wet & dry bulbs) comparing

the difference between each, one can calculate

relative humidity

Psychrometer

Hygrometer – uses hair or chemical plastic strip, the

hair or plastic curls up (contracts) when high humidity

and expands when low humidity – which is attached

to a scale.

Air Pressure

Mercury barometer – is a long tube closed at one end and filled with mercury, at the open end the weight of the air pushes down measuring pressure on a scale – most accurate type.

Air pressure

Aneroid barometer – a mechanical spring inside expands and contracts due to pressure changes Pressure is measured in millibars or inches of mercury (sea level = 1,013 mb) High pressure – clear cool fair weather Low pressure – bad or stormy weather

Wind Vane – measures wind direction - * a wind

vane points to the direction wind is coming

from. Winds are named for the direction they

come from.

Wind direction and speed

Wind Direction = Wind Vane

a Wind Sock

Anemometer – measures wind speed

- in m.p.h., km/hr., or knots

- 1 knot = 1.85km/hr. or 1.15 mph

Precipitation

Rain Gauge – measures the amount of precipitation falling to Earth. Measured in inches or centimeters

- To measure snow use a ruler 1 inch of rain = 10 inch of snow

RAIN GAUGE

Electronic

Rain Gauge

Cloud cover Local cloud cover you use your own visual observation and cloud chart and estimate percent of sky covered (nephoscope)

Nephoscope Instrument used to measure direction, speed, and percent of cloud cover in a given area

Other weather instruments

Radiosonde – a package of instruments attached to a radio transmitter, which is connected to a weather balloon to gather data in troposphere and stratosphere

• Radiosonde

Balloon

Parachute

Radiosonde

A Radiosonde measures

• Temperature,

• Air pressure,

• Wind Speed and Direction,

• Humidity in the upper atmosphere.

• Chemistry of gases like amount of ozone or percent of CO2

Radar • - “radio detection and ranging” Used to

find rain or snow within clouds. Doppler radar gives motion of precipitation in storm path

Satellites - give meteorologist pictures over a wide area used in forecasting and tracking weather

Computers – stores and records data and plots information on maps (computer models) for use by meteorologist in forecasting

Weather maps – gives the total data of an areas weather to help and predict new weather.

Cool down 1. What does an anemometer measure?

Wind speed

2. What is freezing and boiling on the Fahrenheit

scale?

212 degrees