Observing the weather

Name:

Don’t forget to bring your book to Sydney Observatory

Indigenous weatherThe Indigenous people of Australia have evolved cultures that incorporate all aspects of their environments and life including climate change, plant life, animal behaviour, stars, law and family.

For more than 40 000 years they have had to cope with the extremes of weather including thousands of years of winter during the last Ice Age, droughts, fire and flood.

Each Indigenous group have their own unique story of the weather based on observation and an unrivalled connection with nature.

Indigenous Nations of Australia Courtesy NSW Department of Education and Training

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Why study weather at Sydney Observatory?European meteorology, or the study of weather, began in Australia on 14 September 1788 when the First Fleet’s Lieutenant Dawes set up an observatory to look for a comet and to start regular weather observations.

Sydney Observatory, built in 1858, became the centre of weather studies until the Bureau of Meteorology began work in 1908. In 1922 the bureau moved to their purpose-built office nearby, as seen on the cover.

Reconstructed view of William Dawes’ observatory by R Bashford

Web researchOn which ship did Dawes come to Australia?(Hint: it shares its name with the brightest star in the night sky.)

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What is weather?

The Earth is surrounded by a thin layer of gas called the atmosphere.

Weather is the local condition of the atmosphere at a given time.

Climate is the long-term average of conditions that exist in the atmosphere.

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The Sun is the powerhouse behind the weather on every planet in our Solar System.

Did you know some winds even have names! Some include zephyr, mistral and zonda. Can you find any others?

Back at schoolLook up the Beaufort scale on the web. What does it measure and why is it useful?

Heat energy from the Sun causes air to heat and rise. As air cools, it falls.

The never-ending movement of air called w _ _ _ causes the weather we experience every day across the entire planet.

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The weather mapThe Bureau of Meteorology produces weather maps which summarise the weather. The numbers represent the barometric pressure which is a measure of how strongly the atmosphere pushes down on the ground. Join equal pressure readings with a smooth line called an ISOBAR and identify the weather pattern over Sydney. A closed loop of isobars is called a CELL.

Make sure you visit the Bureau of Meteorology website at www.bom.gov.au and look for today’s colour weather map.

Circle the answer that shows the type of cell over Sydney.

• Ahighpressurecellbringingstableweather.

• Alowpressurecellbringingunsettledweather.

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CalibrationTwo of the same instruments can sometimes give us two different readings. This means that instruments require an accuracy check or calibration.

If you are using a thermometer and you read a temperature two degrees higher than the actual temperature, you must subtract two from all of your readings (since your thermometer reads two degrees too high) in order to get the accurate result.

My temperature reading:

Actual temperature as measured by the Observatory’s digital thermometer:

This means I need to add/subtract from my readings.

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CloudsClouds are made of tiny drops of water and ice that are so small they are carried by the wind.

What does the sky look like now?

overcast/rainy

cloudy mostly sunny

sunny

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In the exhibitionFind the exhibit called ‘What was the weather?’ It will tell you what the weather was like on the day you were born!

Enter your birthday on the touchscreen.

Record the data below.

Maximum temperature: °C

Minimum temperature: °C

Rainfall: mm

Back at school the next day• Youandyourclasscanfindoutwhohadthe

hottest birthday, the coldest and the wettest. • Perhapsyourteachercanhelpmakeapie

graph of wet and dry birthdays.

Did you know Sydney’s hottest recorded day was 45.8°C on 18 January 2013. The hottest day ever recorded in the world was in Death Valley, USA, in 1913 at a scorching 56.7°C.

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Find the tipping bucket rain gauge. Read the instructions and carefully adjust the rainfall with the dial.

Q. What does it measure?

A. How much _ _ _ _ falls in an h _ _ r

Look through the cutaway side. What piece of playground equipment does this remind you of?(Hint: it needs weight at both ends to keep working!)

The rain gauge has two buckets so that as one bucket empties, the other is ready to be filled. This means it keeps tipping from side to side and doesn’t stop as long as it’s raining.

New: Now look at the barometer on top of the Westpac building. Is the pressure rising or falling?

Back at school the next dayWas the barometer correct? yes / no

Did you know, as a very loose rule, a high pressure cell brings stable weather and a low pressure cell brings unsettled weather.

Circle your answer below and check tomorrow’s news to see if it was correct.

• Risingpressure (probably clear)

• Fallingpressure (probably cloudy)

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Old and newOld: Visit the Bureau of Meteorology’s instrument enclosure to see where Sydney’s weather measurements are taken.

Which instrument did you see working in the Observatory?

What is recorded by the two instruments that are still working?

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© Museum of Applied Arts and Sciences, 2013

Cover image: Meteorology Building, Observatory Hill, 1928.

Day: Sydney Observatory is open every day (except Christmas Day and Good Friday) between 10.00 am and 5.00 pm. Admission to the heritage building and grounds is free.

Night: Telescope and 3-D Space Theatre tours everynightexceptSundaynights.Pleasevisitour website.

Bookings are essential for night tours. AdmissionfeesandPowerhouseMemberdiscounts apply.

Prepaymentisrequiredforallbookedactivities.

Bookings (02) 9921 3485

www.sydneyobservatory.com

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Meteorology spelling listThese are the words you should be able to spell: weather, meteorology, bureau, isobar, barometer, rain, storm, cyclone, gauge, observatory, humidity, drought, wind, climate, temperature, atmosphere, hail, front, trough, Beaufort, zephyr, hygrometer.

Back at schoolIn the space below construct a weather map from what you have learnt and present a weather report to your class.

4. The relative humidity is a measure of how much water vapour is in the air. 100% humidity occurs in fog. Very low humidity causes lots of small electric shocks from some carpets and clothes.

a. Dry bulb temp °C

b. Wet bulb temp °C

c. Now subtract the wet temp (b) from the dry temp (a) °C

d. Use the table supplied to find the relative humidity %

5. The UV index now:

The UV index is a scale used to tell people how to protect themselves from the Sun’s harmful ultraviolet radiation.

0–2 Low. No protection required. 3–5 Moderate 6–7 High. Slip, slop, slap, seek and slide.8–10 Very high. Avoid the midday sun. 11+ Extreme. Stay in the shade where possible.

6. An anemometer measures wind speed. What is the current speed? km/hr

Now it’s your turn Use the weather instruments carefully to find and record the following data.

1. The temperature now: °C

Compare your temperature to that shown on the signal mast which shows the expected maximum for Sydney. Do they agree? If not, why not?

2. Barometers measure the pressure with which the Earth’s atmosphere pushes down onto the surface. The barometric pressure is: hPa

3. The amount of precipitation or rain can be measured in many different types of rain gauges. How much rain have we collected?

mm