Teachers’ notes – Light at night
Synopsis
Initially, using photographs learners share and discuss their ideas about which areas of the world are lit the most at night and why. Then they consider what light sources might be visible at night in Wales. They share and discuss their ideas about what they think light pollution is and are encouraged to look at the night sky and record their observations. They consider how they think their area is affected by light pollution and how and where they could find more information about it. Learners. use maps of their local area to identify things they think might be lit at night. They explore the purpose of street lights through observation, discussion and information gathering and consider the number of local street lights, their location and frequency, how they are lit and switched on and off and so on. Learners discuss the pros and cons of switching off some street lights at night and consider how a range of people might be affected by it. Using photographs of street lighting learners describe and discuss where they think the light goes, consider what ‘wasted’ light might be and quantify how much light is ‘wasted’ or shining in a direction that does not help it achieve its purpose. They consider how ‘wasted’ light from street lights might be reduced and design and make a model of a street lamp that has as little ‘wasted’ light as possible. Finally, learners consider how bright lighting at night might affect different living things.
Curriculum links
Interdependence of organisms:
7.how human affects the local environment, e.g. litter, water pollution, noise pollution
How things work:
5. how light travels and how this can be used
Skills
Communication: 1, 2 & 3
Enquiry – Planning: 2, 3 & 5
Enquiry – Developing: 5, 6 & 7
Enquiry – Reflecting: 5 & 6
Activities
Tab 1
/ The first tab in this activity provides learners with a dramatic photograph that shows the light given off across the Earth at night time. Learners are encouraged to share and discuss their ideas about what they think the photograph shows. Rollover questions are provided to support discussion and prompt the learners to consider which areas of the world are lit the most and why. They might look at maps and atlases and compare them with the photograph.Tab 2
/ The aim of this tab is for learners to consider what light sources might be visible at night. Learners are provided with six photographs of different areas of Wales. They are asked to share and discuss their ideas about how they think the areas shown in the photographs would look like at night time. Learners are encouraged to identify light sources in the photographs that are likely to be visible at night and consider what might not be visible in the photographs but might be at night, for example, stars.Tab 3
/ This tab directly asks learners to share and discuss their ideas about what they think light pollution is. Open discussion and a sharing and explaining of ideas are encouraged. Learners are asked to consider what they think causes light pollution and what effects of light pollution might be observable. They should look at the night sky and record what their observations. They might also consider how they think their area is affected by light pollution and how and where they could find more information about it.Tab 4
/ The aim of this tab is for learners to use maps of their local area to identify things they think might be lit at night. Learners are asked to explain why they think different things might be lit at night. They are encouraged to draw and write their ideas and to consider what might be the brightest things visible in their area at night.Tab 5
/ It is likely that street lighting will have featured frequently in previous tabs as a light source that will be visible in many areas of Wales at night time. The aim of this tab is for learners to explore the purpose of street lights through observation, discussion and information gathering. They might consider the number of local street lights, their location and frequency, how they are lit and switched on and off and so on. Learners are encouraged to use this information to explore and predict the number of street lights in Wales and how much it costs to light them all each year. Internet searches may not provide absolutes in terms of answers but will provide information that can be used to further discussion. For example, in October 2008 the South Wales Argus reported that Torfaen has 13,344 street lights that will cost £900,000 to light in 2009/10.Tab 6
/ The aim of this tab is for learners to discuss the pros and cons of switching off some street lights at night. Learners might be aware of the current economic climate and the need for councils across Wales to look at cost saving exercises which may be a starting point for discussion. Powys, for example, is one Welsh authority that has been involved in switching off a number of street lights at night in recent times. They are asked to consider the arguments for and against turning off street lights and to share and discuss their ideas.Tab 7
/ This tab aims to encourage learners to consider the effects of turning off street lights at night. They are asked how a range of people might be affected by street lights being turned off. A randomiser generates the following range of people in word form:1. local councillor
2. elderly person
3. child
4. parent
5. shop owner
6. energy supplier
7. environmentalist
The tab provides a recording box in which learners are encouraged to note the pros and cons for each person of street lights being turned off.
Tab 8
/ This tab utilises the tab within a tab structure. The first tab provides learners with two photographs of different street lights. They are asked to describe and discuss where they think the light goes in each photograph. Both photographs may be enlarged and learners are able to draw and write on them.Learners are asked to consider what ‘wasted’ light might be and to quantify how much light is shining in a downwards direction and therefore fulfilling its purpose and what percentage of light is ‘wasted’ or shining in a direction that does not help it achieve its purpose.
Learners are encouraged to observe and draw the street lights near where they live.
By clicking on the ‘Next’ button a second tab is opened up. This tab encourages learners to share and discuss their ideas about how ‘wasted’ light from street lights might be reduced.
The learners are encouraged to design and make a model of a street lamp that has as little ‘wasted’ light as possible.
Tab 9
/ The final tab in this activity asks learners to consider how bright lighting at night might affect different living things. A randomiser generates the following living things for the learners to consider:1. Migrating birds – can affect their flight patterns making it difficult for them to follow their usual migration paths.
2. Moths – as most moths only come out at night then high levels of light pollution can make daylight hours appear longer and cause disruption to the pattern of their usual lives.
3. people living in a city
4. Astronomers – something called ‘skyglow’ occurs because light emitted upwards into the sky scatters causing an orangey glow especially above cities and large towns. This ‘skyglow’ will often affect sensitive instruments collecting light readings from distant light sources, such as galaxies and stars.
5. Bats – All bats are nocturnal. There is evidence they sample light conditions before emerging at night. High levels of light pollution are likely to reduce the amount of time bats have to look for food and are thought to disrupt their natural behaviour.
6. Sea turtles – light pollution is thought to affect where female turtles lay their eggs and to increase the risk of predators.
The tab provides a recording box in which learners are encouraged to record their ideas.
Unit 3.4.6 teachers’ notes – Light at night1