Weather Instruments

Marie Jaja Tan Roa Schools Division of Ilocos Sur Sta. Maria West Central School
Weather
Lesson 62-65

Weather Song (Tune: Bingo)
There was a time when we were wet
and rainy was the weather
r-a-i-n-y, r-a-i-n-y, r-a-i-n-y
and rainy was the weather
There was a time when we were hot
and sunny was the weather
s-u-n-n-y, s-u-n-n-y, s-u-n-n-y,
and sunny was the weather

There was a time when we were cool
and windy was the weather
w-i-n-d-y, w-i-n-d-y, w-i-n-d-y,
and windy was the weather
There was a time when we were cool
and cloudy was the weather
c-l-o-u-d-y, c-l-o-u-d-y, c-l-o-u-d-y,
and cloudy was the weather

Day 1What is Weather?
 Weather refers to the general condition of the
atmosphere over a particular place on a day-to-
day basis.

 The sun rays hit earth
and absorbs the heat
unevenly.
 This uneven heating
causes changes in
weather.

What causes weather?

 Weather condition affects our daily life.
 We do activities depending on the weather
condition in our community.

Temperature
Wind
Air Pressure
Humidity (Air Moisture)
Precipitation and Clouds

How to predict weather?

Air temperatureThermometer
Wind speedAnemometer
Wind directionWind vane
Air pressureBarometer
Relative HumidityPsychrometer
PrecipitationRain Gauge
Cloudiness(scale)
To predict weather,
certain apparatus is
use to measure the
temperature, air
pressure, wind,
humidity,
precipitation and
cloudiness of the
surroundings.

How is temperature
measured?

 Air temperature is the degree of hotness or
coldness of the air at a particular time and
place.
 It is measured in degrees Fahrenheit (˚F)or
degrees Centigrade or Celsius (˚C).
 Temperature is measured by an instrument
called a thermometer.

Temperature can be
measured using a
thermometer such as the
liquid-in-glass type, where the
liquid (alcohol) in the bulb
expands and rises up a
capillary tube.
1. Thermometer measures Air temperature

 The left side of the
thermometer shows the
Celsius reading.
 Its highest number is 100
while its lowest is 0.
 The red column of the
thermometer tells what the
actual temperature is.

 The earth’s surface
does not heat evenly
due to sunlight hitting
the earth at different
angles.
 Air temperature is at
its highest at noon
and lowest at
morning.

Temperature are measured in the shade, so
that the heat of the sun does not heat up the
instrument being used.

Do the following activity:
Activity 1: Measuring Air Temperature
Objective:
1. Measure the air temperature using a
thermometer
2. Read and record the air temperature
correctly
3. Identify possible sources of error in
measuring air temperature.

 room thermometer
 copy of activity sheet
 Pen/marker
 Manila paper
What you need

1. Given a thermometer, go to your
assigned area and find a place where
you can hang your thermometer set up
1.25 meters (4 feet) above the ground.
2. Record the temperature read.
What to do:

3. Measure the air temperature of the
following places in the school premises.
a. Inside the classroom
b. Under a shady tree
c. At the middle of the playground
d. In the study shed
e. On the corridor
What to do:

Place
Temperature in
degrees Celsius
Time
recorded
1. Inside the classroom
2. Under a shady tree
3. At the middle of the
playground
4. In the study shed
5. On the corridor

Guide Question/s:
1.What can you say about the temperature of
the different areas you have measured?
2.Is air temperature the same in all areas?
Support your answer.
3.What are possible sources of error in this
experiment?

 How to use and interpret readings of room
thermometer?
 Based on your activity, what did the data of air
temperature tell you?
 At what time of the day is the temperature at its
highest/lowest?
 At what weather condition is the temperature
high/low?
 What factors affect the day’s temperature?

 To predict the weather, the temperature
of the surroundings is measured.
 A thermometer is used to measure air
temperature.
 Sunlight affects air temperature.
 Air temperature is at its highest at noon
and lowest at morning.

What happens to air
when heated?
Day 2

 Hot air expands and rises. The particles get
farther apart, become less dense and they
get lighter.
 Cold air contract and sinks. When the air
particles get closer together, it makes the air
heavier or more dense.
 This movement of air is called convection.

 Air moves from areas of high pressure to
areas of low pressure.

The movement of air continues as long as a
place is warmer than other places.
Moving air is called
Wind can be described by stating its speed and
direction.

Speed refers to how fast the wind
blows. It is usually expressed in
kilometers per hour as in 40km/h.
Direction refers to the wind’s
movement from one spot to
another. The four general
directions are North, South, East,
and West.
Wind direction and wind speed
and basic indicators of weather.

 Wind direction is from a cooler area to a
warmer area.
 In the evening, the cold wind blows from
land to sea. This is called land breeze.
 At daytime, wind blows from sea to land.
This is called sea breeze.

 The wind blows from different directions.
 The wind is named after the direction from
which it is blowing.
 A wind blowing from the north is called a north
wind.
 A wind blowing from the south is called a
south wind.
 Meteorologist uses wind vane to tell the
direction of the wind.

The wind vane tells the wind
direction.
As the wind blows, the figure on
the vane spins.
The direction of the wind is
always given by the blowing
from the north.
Wind vanes are often seen on
top of buildings.
2.1 Wind vane measures wind direction

Wind direction may change from day to day.
When the weather is fine, the wind may blow from any
direction.
Easterly and northeasterly winds may prevail during fair
weather.
Northeast wind is called Amihan

Heavy rains are usually brought about by
southwesterly winds.
Southwest wind is also called Habagat.

 Wind speed may be calm in the morning
or light to gentle in the afternoon.
 It usually changes from time to time
during the day.

Anemometer is used to find how fast the
wind is blowing.
The harder the wind blows, the faster the
cup spin.
The anemometer has a speedometer.
Speedometer measures wind speed in
kilometers per hour.
2.2 Anemometer measures wind speed

When the air is calm, the anemometer
barely moves. The cups spin slowly when
the wind gently moves.
When the wind is strong, the cups move
fast.

Wind Speed Wind Effects on Tree
Calm Leaves remain still
Light Leaves rustle
Gentle Leaves and small twigs move
Moderate Small branches move
Strong Large branches move
Gale Twigs break

The Beaufort Scale
 The Beaufort scale is an empirical
measure for describing wind intensity
based mainly on observed sea
conditions.
 Its full name is the Beaufort Wind Force
Scale.

Do the following activity:
Activity 2A: Make you own wind vane and anemometer
Objective:
1. Make a wind vane and anemometer
independently.

For Wind vane
 Pencil
 Pin
 Cardboard
 cup
What you need
For anemometer
 4 cups
 2 Hard straw
 Pin
 pencil

1. Cut the cardboard into an arrow with a wide
tail at one end. Mount it on a pencil with the
use of a pin.
2. Make a hole at the bottom of the center of the
cup, attach the pencil. Make a chart of
directions on the cup.
3. Use your wind vane to observe the direction of
the wind outside.
What to do: Wind vane

1. Pin two straws across each other.
2. Attach the plastic cup to each end of
the straw.
3. Mount the straw on the pencil’s eraser
using a pin.
4. Go outside and observe how the fast
the cups rotate.
What to do: Anemometer

Guide Question/s:
1.Using the wind vane, what is the direction of
the wind?
2.Using the anemometer, how strong is the
wind?
3.How does wind speed and wind direction
measured?

The wind is moving air. The wind is named after the
direction from which it is blowing.
Wind direction is from cooler area to warmer area.
Northeast wind is called Amihan, Southwest wind is
also called Habagat.
A wind vane tells wind direction.
The wind moves at different speeds.
An anemometer is used to measure the speed or
velocity of the wind.
Wind speed and wind direction are basic indicators of
weather.

Day 3
Does air have weight?

 Do any of the following activities to find out.
1. Water glass trick
2. Grab a tissue
3. Egg in a bottle

How is it possible?!

1. Water glass trick
 The water in the glass does not spill. Air
particles below the card push the card up. Air
particles outside the card exert an upward
force on the card. This upward force is
greater than the force exerted by water
particles.
 This weight of the air is called air pressure.

2. Grab a tissue
 The air pressure inside the glass is strong
enough to keep the water out and the tissue
dry.
3. Egg in a bottle
 The match uses up the air inside the bottle.
Once that happens, the pressure outside the
bottle is greater and pushes the egg down into
the bottle.

What is air pressure?

 Air pressure is the weight of air molecules pressing
down on Earth.

 Air pressure is greatest at the surface of earth
because there is more of the atmosphere above
you to push down on you.
 Air pressure changes with the height and also
when air warms up or cools down.

 As you reach higher
elevation, air
pressure decreases.
 There are fewer air
particles above you
to push down on
you, so the force of
the air will be less.

usually results in
.
usually
results in
: stormy,
cloudy, overcast.

Meteorologists use
barometers to measure the
pressure of the air when
making weather forecasts
and studying weather
patterns.
It is measured in units
called millibars.
3. Barometer measures Air pressure

Air pressure or atmospheric pressure is the
weight of air molecules pressing down on Earth.
Barometer is use to measure air pressure and is
measured in millibars.
Low air pressure usually results in bad weather.
High air pressure usually results in good weather.
Air pressure changes with the height and also
when air warms up or cools down.

Day 4
Is there water in the air?

 Water is added to the air by the process of

 Humidity is the
amount of water
vapor present in the
air.
 If the air is holding
ALL the moisture it
can hold, the air is
SATURATED.

 Relative humidity is the measure of the amount of
water vapor in the air compared to the maximum
amount of water vapor it can hold.
Water capacity of air at different temperatures.

 As the air gets warmer, the amount of water
vapor that the air can hold increases.

 The humidity
of an air mass
depends a
great deal on
the
temperature of
the air.

 Warm air can hold more water vapor than
cold air.
 Reason: warm air molecules are more
spread, more space for water vapor to fit in
between. As the air mass cools, the
spaces between the air molecules begins to
shrink reducing the amount of space for the
water vapor.

 When the air reaches its maximum amount of
water that it can hold (saturation point) the
water vapor will start to condense forming
clouds and precipitation.
 The higher the humidity, the greater the chance
of rain or snow.

Psychrometer is made of two thermometers.
One is covered with a wet cloth. When air moves
over the wet cloth, evaporation occurs and lowers
the temperature on that thermometer.
If you compare the temperature on the two
thermometers, you can get the relative humidity.
4 Psychrometer measures relative humidity

When a meteorologist wants
to measure the temperature
in the room, he removes the
wet bulb from the water.
Depending on the design of
the psychrometer, the wet
bulb either swings around or
remains stationary.

As the water evaporates, it cools the wet bulb.
By measuring the cooling of the wet bulb, the
meteorologist can tell how much water
evaporates. This, in turn, tells her how humid the
air is.
Moist air allows only a little water evaporate,
and the wet bulb barely changes temperature.
Dry air absorbs a lot more moisture, cooling the
wet bulb quite a bit.

Ex. 1
Dry Bulb = 14 degrees C
Wet Bulb = 10 degrees C
Difference is 14-10 = 4
1st – look at dry bulb reading (14)
2nd – find difference (4)
3rd – RH is where they meet = 60%

RH = 85 %
Dry Bulb= 4 degrees
Wet Bulb= 3 degrees

Ex. 3
Dry Bulb = 6 degrees C
Wet Bulb = 6 degrees C
RH = 100%

 Humidity is the amount of water vapor present in
the air.
 Relative humidity is the measure of the amount
of water vapor in the air compared to the
maximum amount of water vapor it can hold.
 The higher the humidity, the greater the chance
of rain or snow.
 Psychrometer is made of two thermometers, it
measure humidity.

Day 5
How are clouds formed?

 Clouds are a mixture of air, water vapor, and dust.
 Warm air and water vapor rise up into the sky. As they
get colder, the water vapor condenses.
 It turn into millions of tiny water droplets.

1. Convection resulting from differential heating
2. Mountain ranges that serve as barriers to moving air
masses; and
3. The moving of air masses with different densities

1. Sunshine warms bare soil faster than grass.
On sunny day, humid air rises from these
areas.
2. As humid air rises and cools, the water vapor
in its starts to condense and forms clouds.
3. The clouds grow bigger as more pockets of
rising warm air feed them with droplets of
water.

There are four
types of clouds
1. Stratus
2. Cumulus
3. Cirrus
4. Nimbus

Cloud names that
begin with STRATO
are LOW
ALTO are at the
MIDDLE level
CIRRO are very
HIGH

Meteorologist can often predict the weather by
just looking at the shapes of clouds and watching
how they change.
Cloud cover is the fraction of the sky covered in
clouds.
Cloud is measured by observation and is
measured in oktas.
5. Okta grid measures cloud cover

The amount of cloud which can be seen in the
sky
EXPRESSION CLOUD COVER
Sky clear (SKC) No clouds
Few (FEW) 1-2 oktas
Scattered (SCT) 3-4 oktas
Broken (BKN) 5-7 oktas
Overcast (OVC) 8 oktas

 At night, the earth gives off heat.
 Cloudy night feels warmer while cloudless night feels colder
because of the reflection of heat coming from the earth’s
surface.

How is observing clouds helps in
predicting weather?
Day 6

 Precipitation is any form of moisture that falls on
Earth.
 There are four kinds of precipitation: rain, snow,
sleet, and hail.

 The rain gauge measures
the amount of rainfall.
 A rain gauge measures
not only rainfall, but also
all other forms of
precipitation.
6. Rainfall is measured using rain gauge.

 Weather is the general condition of the atmosphere
over a particular place on a day to day. It may be
sunny, cloudy, windy or rainy.
 Weather conditions affect our daily lives and must
be considered in planning our daily activities.
 The elements of weather are: air temperature, air
pressure, humidity, wind speed and wind direction,
cloudiness and precipitation.

Air temperatureThermometer
Wind speedAnemometer
Wind directionWind vane
Air pressureBarometer
Relative HumidityPsychrometer
PrecipitationRain Gauge
CloudinessOkta scale
 Meteorologists are experts
who study the day-to-day
variations in the weather.
They are the ones who
prepare the weather
forecast for any given day.
 Weather instruments are
used by meteorologist to
predict weather.

 Weather changes from time to time because the
temperature of air changes.
 Changes in air temperature result in changes in air
pressure and humidity.
 A high pressure indicates fair weather while a low
pressure indicates rain or storm.
 When air is warm, humidity is low; when it is cold,
humidity is high.
 Clouds are signs of changes in weather. They also
protect the earth from too much heat coming from the
sun.

1. What are the elements of weather?
2. Explain why air moves.
3. Why is humidity low when air is warm?
4. Why is air pressure low when air is cold?
5. Why are there changes in air movement, air
pressure and humidity?

6. Explain how clouds are formed.
7. Describe each of the different kinds of clouds.
8. In what way do clouds lessen the amount of
heat received by the earth.
9. What happens to heat in the atmosphere?
10.Why does the heat that reaches the earth
contain less harmful rays?
11.What happens when clouds reflect heat back
to the earth?

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