Keeping warm
Upper Primary Science, Geography and Maths
Using a thermometer
Overview
In activity one, children will be introduced to thermometers and their uses, and have the opportunity to practise taking temperature readings using thermometers with different scales. They will link the measurement of temperature to how hot or cold things are.
In activity two, children will take careful readings of outside temperature during the day and try to explain findings in terms of weather conditions. Only a short time is needed at hourly intervals to take the temperature readings throughout the day.
Objectives
Children should learn:
to use a thermometer to make careful measurements of temperature, using standard measures.
that temperature is a measure of how hot or cold things are and that something hot will cool down and something cold will warm up until it is the same temperature as its surroundings.
to explain temperature and temperature changes using scientific knowledge and understanding
Lesson plans
Activity one
Introduction to using thermometers
Using slides 1 and 2 the children discuss uses of thermometers and are taught how to handle thermometers safely. They are then given a selection of thermometers to handle and examine.
Teach the children how to read the thermometer scale using the thermometer ITP.
Activity
Have containers of water at different temperatures ready, positioned so that all the children will be able to take temperature readings during the activity. Tell the children they will be practicing taking temperature readings for each container of water and the empty container which will be at room temperature. Remind the children that care will be needed when measuring the temperature of very hot water. Children record their measurements using the measuring temperatures worksheet and note the time. They will take a second reading an hour later.
While waiting to take the second reading, use the rest of the slides to practice reading temperatures, discuss temperature as a measure of how hot or cold things are and predict what will happen to the temperature of the water in the containers (the water will cool down or warm up to reach room temperature).
This will be a good time to introduce activity two, using slides 9 and 10 in preparation for starting the activity at 9a.m. when planned.
Plenary
Ask the children to measure the temperatures again and complete the worksheet.
Lower ability groups will need support to take temperature readings and complete the worksheet.
Lesson resources
You will need:
Containers of water at different temperatures including below room temperature and an empty container at room temperature.
Measuring temperatures worksheet
Activity two
Measuring the outside temperature
Place a thermometer in a safe place outside in the shade, away from direct sunlight.
Children take temperature readings at every hour and record them, using graph with or without scale.
Plenary
When children have completed all readings and constructed their bar graphs, discuss the results and ask children questions about their findings.
Ask the following:
What was the temperature at 9am?
What was the temperature at playtime?
How did the temperature change during the day?
What was the warmest time of the day?
Can you explain why the temperature changes during the day?
You will need:
Slides 9 and 10 from using a thermometer slideshow (above)
Outside temperatures worksheet
Outside temperatures worksheet(without scale).
Web page reproduced with the kind permission of the Met Office
Storm surges are mainly caused by the effect of the wind on the sea, not changes in atmospheric pressure. The effect of wind on the sea surface is known as wind stress. The wind stress on the surface of the sea causes the water level on a coast to rise if the net transport of water is towards land and to fall if it is away from land.
Flooding of the Thames on 6th -7th January 1928 highlighted the need to find ways of forecasting storm surges. However, the real push to investigate storm-surges was on 31st January and 1st February 1953, when, a surge exceeding 2.7 metres at Southend in Essex and 3.5 metres in parts of Holland killed 307 people died in eastern England and 1,800 in the Netherlands. The storm that caused the 1953 surge was among the worst to hit the UK in the 20th century. Before the storm’s low pressure and storm-force northerly winds raised water levels in the southern North Sea, hurricane-force winds blew down more trees in Scotland than were normally felled in a year; and a car ferry, the Princess Victoria, on passage from Stranraer in Scotland to Larne in Northern Ireland, sank with the loss of 133 lives. Only 41 of the passengers and crew survived. Nowadays, surges are forecast with considerable accuracy and storm-surge barriers are in place in the most vulnerable places in the Low Countries and eastern England, one of them on the Thames a (south of Greenwich).
When pressure falls by one millibar, sea level rises by one centimetre. Thus, a deep depression can cause sea level to rise 60 or 70cm above the level predicted purely on the basis of tidal theory. The pressure-induced rise in sea level caused by a tropical cyclone can be much greater, maybe a metre or more.
One of the most energetic and destructive of all weather systems are tropical cyclones. The hurricane-force winds can reach 50m/s and torrential rain falls from their towering cumulonimbus clouds.flooding The winds can cause disastrous surges on coasts and the downpours of rain can cause serious flooding. Power and water supplies are disrupted, buildings are damaged, crops are destroyed, people and livestock are drowned, bridges collapse, roads and railways are undermined or blocked by debris, and beaches are scoured. Tropical cyclones nearly always leave behind a trail of destruction and misery.
Flash floods are exceedingly dangerous. When water cannot percolate into the ground, it runs off the surface as it would from impermeable concrete. This is particularly so when the ground is very wet or when baked hard after a hot dry spell. Potholers can be especially at risk, such as on 24 June 1967, when five drowned in Yorkshire. The water which fell in a heavy thunderstorm after a spell of dry weather ran off rapidly into underground streams and caverns at Mossdale. The rise in water levels below ground was too rapid for the potholers to scramble to safety.
In terms of water flow, the Mississippi is the sixth largest river in the world. Its annual average flow rate is 14,000 cubic metres per second and it discharges into the Gulf of Mexico 580 cubic kilometres of fresh water per year. The greatest flows occur in the period March to May and the least in the period August to October. A large proportion of the United States is drained by this river.
There was rain, more rain and even more rain in northern California soon after Christmas 1996. From 29 December 1996 to 4 January 1997, depression after depression from the central Pacific brought rain to northern California. As the air was unusually warm, a consequence of the precipitation was that large amounts of snow melted. During the week of the storms, 61 cm of rain was recorded. Significant flooding occurred in northern California and southern Oregon and 43 counties were declared disaster areas. Flooding occurred rapidly because soils became saturated and amounts of snowmelt were large. Flood-control reservoirs could not cope, as their storage capacity was no more than moderate because of near-normal rainfall and run-off prior to the onset of the severe weather. Levee failure occurred on several rivers.
In many parts of the world, there are serious health risks after disastrous flooding. Mosquitoes, flies and other insects may become more abundant than usual, as the filth, debris and stagnant water left by the floods provide suitable breeding conditions. Consequences may include out-breaks of typhoid, dysentery and encephalitis. Rats and mice displaced from their natural habitats may find conditions to their liking in houses, sheds, barns and other buildings.
In some parts of the world, snakes also become a problem after flooding, as they, too, are displaced from their natural homes by the water. Quite often, they appear inside houses. However, snakes can be beneficial, as they help to reduce populations of rodents.
Some of the most fertile land in the world lies beside rivers, the Nile valley being the classic example. For thousands of years, the people of Egypt have relied upon the waters of the Nile to overflow their banks every year, carrying with them fertile silt that makes agriculture possible. The flow of this river is nowadays controlled by means of the Aswan High Dam, an operation that can have its advantages and disadvantages. Salinity levels in the Nile Delta have increased, for example, because the outflow of fresh water from the river is much less now than before the High Dam existed. On the other hand, availability of water from the lake behind the dam, Lake Nasser, has allowed water levels downstream to be maintained in drought years, thus benefiting agriculture when in olden times crop failure and famine might have occurred.
The Ganges Delta is another place where flooding brings benefits for agriculture. Here, every June to October, the waters of the Ganges, Brahmaputra and other rivers overflow and inundate the countryside. There is, however, no equivalent of the Aswan High Dam to control the waters of the Ganges Delta. Sometimes, crops are destroyed, hamlets ruined and humans and animals drowned.
The heavy rains brought by tropical cyclones can help revive crops and replenish water supplies. Sometimes, fruit trees have flowered and borne fruit a second time after the passage of a cyclone. Sometimes, floods have flushed away mosquito breeding areas. There is a danger, however, that residual pools of water will, in turn, become mosquito breeding areas.
This is a drought which affects how farmers can use their land. An agricultural drought usually means there is not enough water for the crops to grow as there is a lack of soil moisture. It can also affect livestock such as cows and sheep.
Hydrological droughts are ones which there is a lack of water at the surface of the earth, resulting in less water in streams, lakes and reservoirs and can impact on the use of water for houses and industry
This is usually simply defined as a period of time where there has been less rain recorded. Rainfall amounts can vary by duration (i.e. time the rain fell for) and the intensity of rainfall (how hard it was raining). Meteorological drought is usually recorded in the time there has been little or no rain for e.g. months or years.
A Socioeconomic drought is when physical water shortages affects the lives of people; such as their health and quality of life. It can also affect the supply of food and materials and so affect the economy.
The Climate Change Schools Resources were developed by the Climate Change Schools Project, based at the then Science Learning Centre in Durham and led by Krista McKinzey. A large number of teachers and schools in North East England were involved in their development.
One of these is lightning, though the possibility of its occurrence may be indicated indirectly in a forecast or station report as ‘thundery showers’. In fact, lightning is not such a risk to sailors as it might at first appear. Boats are surrounded by a very good conductor of electricity – water – and unless the boat suffers a direct hit, which is unlikely, the current is dissipated much more quickly than on land.
Mountain tops are often hidden by clouds, which can result in people getting lost. But why does this happen? Clouds are formed by the condensation of water vapour in rising air. Air is very moist (holds lots of water) when it is near the sea or when there is persistent rain. In the UK the cloud base (i.e. the bottom of the clouds) is often below 1000m, so low in fact that much of the time the clouds cover the mountain tops. Cloud cover on the mountains is particularly common in the west of the UK where the moist air blows in across the Atlantic. Clouds can be supercooled i.e. water remains as a liquid even when the temperature is below freezing (0°C)! these droplets of water freeze when they hit solid objects such as fences and even people. The soft ice can build up into a think layer, known as rime which can cause as much difficulty for walkers as lying snow.
The rain and snow which falls over mountains tends to come from nimbostratus clouds, and occasionally cumulonimbus clouds, tend to be heavier and longer lasting than over nearby low lying areas. This is because the air is forced to rise over the mountains, causing the air to cool as it rises condensing the water from a gas to liquid; forming more clouds. However strong winds at the mountain top can blown the heavier rain over the mountain top, so the heaviest rain will not necessarily be at the highest point. Waterproof clothing and footwear on mountains is essential as there can be heavy rain, driving winds and mountain streams can become deep quickly. Deep depressions coming in from across the West coast of the UK can bring heavy rain and strong winds to the UK. Snow combined with wind can be life-threatening on a mountain top.
The higher up the mountain we climb, the colder and windier it usually gets so that the wind chill factor increases. Warm clothing on the top of mountains is definitely needed. On the Munros (the Scottish mountains with tops above 3000m) it can be 10°C cooler at the top of the mountain in comparison to the valley bottom below. In fact air can cool by 6°C in every 1000m and sometimes as much as 10°C. But why does the air get cooler and windier? It is windy high up in the atmosphere as the effect of gravity is reduced and cooler because air temperatures decrease as you get closer to the poles. Therefore gale force winds are stronger and more common at the top of mountains than at sea level. Winds also get faster around mountains as they do around tall buildings in our towns and cities. Over the Himalayas winds of 150km/hr (approximately 42 metres per second) are not uncommon!
Snow combined with poor visibility in cloud also causes problems because shadows disappear. Navigation becomes almost impossible and can lead to blundering into dangerous places ‘ even over the edges of cliffs. This is known as a ‘whiteout’. If there is already much lying snow and a risk of the cloud base descending onto the hills, many climbers often consider it wise to abandon the trip.
Local winds occur on a small spatial scale, their horizontal dimensions typically several tens to a few hundreds of kilometres. They also tend to be short-lived lasting typically several hours to a day. There are many such winds around the world, some of them cold, some warm, some wet, some dry. There are many hazards associated with the winds.
This wind is caused by thermal (heat) processes. Anabatic (upslope) winds occur over slopes which are heated by the sun. Air which is in contact with slopes that are warmed expands upward and cool and sinks over neighbouring valleys (see diagram). Anabatic winds are usually slow, at only 1-2m/s and are rarely important expect near coasts where they can increase the strength of sea breezes.
Katabatic (downslope) winds occur over slopes which are cooled. Katabatic winds occur where air in contact with sloping ground is colder than air at the same level away from the hillside over the valley (see diagram). Katabatic winds are nocturnal phenomena in most parts of the world (i.e. they tend to happen at night) as there is surface cooling, especially when there is little cloud and due to lack of heating by the sun.
The bora is a strong, cold and gusty north-easterly wind which descends to the Adriatic Sea from the Dinaric Alps, the mountains behind the Dalmatian coast (the coast of Croatia). It is a winter phenomenon that develops when a slow-moving depression is centred over the Plain of Hungary and western Balkans so that winds are blowing from the east towards the Dinaric Alps. These mountains form a barrier which trap the cold air to the east of them whilst the Adriatic coast remains comparatively mild. Gradually, though, the depth of the cold air increases until the air flows over passes and through valleys to reach the Adriatic Sea.
The Föhn is a warm, dry, gusty wind which occurs over the lower slopes on the lee side (the side which is not directly exposed to wind and weather) of a mountain barrier. It is a result of forcing stable air over a mountain barrier. The onset of a Föhn is generally sudden. For example, the temperature may rise more than 10°C in five minutes and the wind strength increase from almost calm to gale force just as quickly. Föhn winds occur quite often in the Alps (where the name Föhn originated) and in the Rockies (where the name chinook is used). They also occur in the Moray Firth and over eastern parts of New Zealand’s South Island. In addition, they occur over eastern Sri Lanka during the south-west monsoon.
The danger of a Föhn where there are steep snow-covered slopes is that avalanches may result from the sudden warming and blustery conditions. In Föhn conditions, relative humidity may fall to less than 30%, causing vegetation and wooden buildings to dry out. This is a long-standing problem in Switzerland, where so many fire disasters have occurred during Föhn conditions that fire-watching is obligatory when a Föhn is blowing.
The mistral is also a strong and often violent wind. It blows from the north or north-west down the Rhône Valley of southern France and across the Rhône Delta to the Golfe du Lion and sometimes beyond. Though strongest and most frequent in winter, it may blow at any time of year and develops when stable air is forced through the Rhône Valley. It occurs when a depression is centred over north-west Italy and the Ligurian Sea and a ridge of high pressure extends north-eastward across the Bay of Biscay.