IELTS listening actual test: Part 4: SW40 11/01/2025 ( answer+ transcript) – YouTube Dictation Transcript & Vocabulary

1.now turn to section four section four you will hear a lecturer giving a talk to design and Technology students about a new device which uses the sun to purify water first you have some time to look at questions 31 to 40 now listen carefully and answer questions 31 to 40 for many parts of the world today a lack of clean drinking water is a major problem in some developing areas bore water which is water that comes out of the ground is the only water available unfortunately more water may be dangerous to drink because it contains excessive amounts of salts in recent months I've been working with a research team to develop a device that will help solve this problem what we came up with is a solar water purifier which we have called the sw40 and this device not only makes bore water drinkable it can even process sea water in fact it even passed the rigorous testing standards applied by hospitals to determine whether water is sterile enough for use there the only problem we do face at the moment is with its manufacturing the present method involves a process called vacuum forming which tends to be rather slow we'd like to change to an injection mode of process which is much faster but would cost quite a lot to switch to around 1 million Australian dollars there are a number of private companies that are very keen to go into partnership with us over this but my preferred option would be a global Aid agency known as health International that sponsors projects like like ours it has a long history of working in these areas and although it may take a little longer to get an agreement it should mean a better deal all around so just how useful is this device of ours well the amount of pure water it is capable of producing each day varies as the amount of sunlight available varies however on a hot day when the temperature is around about 25 to 30° C with the sun shining clearly through a blue sky it produces anywhere from 7 L per day to as much as 9 lers now most people can survive on 1 to 2 lers per day so even under difficult conditions one family could live off one of these devices so a normal-sized village would require several of these to supply all its needs Okay so so let's look at the device in more detail it weighs 8 kg and is the size of a mediumsized suitcase the sw40 has no filters no electronics no moving parts and uses no chemicals so how does it work well there's a rectangular box with a glass lid on it and on the edge of the box is a steel frame to hold everything together and inside the box is a piece of black plastic which is divided up into Pockets you need an incline so the water flows through the device the optimum is 12.5 de to the horizontal although it can be 1 or 2° above or below that impure water is piped in at the top of the box and flows down through the little pockets until they're all full you then let mother nature in the form of the Sun do its work as it shines through the glass window it produces infrared light which heats the water at the same time ultraviolet light from the sun or UV as we more commonly call it is also radiated if there are germs present in the water prolonged exposure to this type of light will kill them then as the temperature of the water rises due to the sun's heat the water vaporizes and condenses on the underside of the glass panel the droplets of water slowly run down the glass to a collection tank ready to be taken away for drinking or whatever so that's basically how it works now what this means that is the end of section four you now have half a minute to check your answers e e e