Creating Artificial Gills - IELTS Listening Answers & Explanations
From IELTS Practice Test Plus 3 Academic Listening Test 2 · Part 4 · Questions 31–40
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Questions
Questions 31–40 Note Completion
Complete the notes below.
Write NO MORE THAN TWO WORDS for each answer.
Creating artificial gills
Background
- Taking in oxygen : mammals - lungs; fish - gills
- Long-held dreams - humans swimming underwater without oxygen tanks
- Oxygen tanks considered too 31 and large
- Attempts to extract oxygen directly from water
- 1960s - prediction that humans would have gills added by 32
- Ideas for artificial gills were inspired by research on
- fish gills
- fish swim bladders
- animals without gills - especially bubbles used by 33
Building a simple artificial gill
- Make a watertight box of a material which lets 34 pass through
- Fill with air and submerge in water
- Important that the diver and the water keep 35
- The gill has to have a large 36
- Designers often use a network of small 37 on their gill
Main limitation - problems caused by increased 38 in deeper water
Other applications
- Supplying oxygen for use on 39
- Powering 40 cells for driving machinery underwater
Answers & Explanations Summary
| # | Answer | Evidence | Explanation |
|---|---|---|---|
| Q31 | heavy | You need special training and it’s generally agreed that tanks are too heavy and big to enable most people to move and work comfortably underwater | Excerpt/Transcript Explanation: The transcript states that oxygen tanks are not easy to use because they have too much weight and are very large, which stops people from moving easily while they are under the water. Answer Explanation: The answer 'heavy' means that oxygen tanks for diving have a lot of weight, making them difficult to carry or move. Reason For Correctness: The correct answer 'heavy' is determined by the speaker's discussion of the problems with traditional scuba diving equipment. She notes that while humans want to breathe underwater, using oxygen tanks is difficult. Specifically, she identifies two main physical drawbacks: the tanks weigh a lot (they are heavy) and they take up a lot of space (they are big), which makes moving underwater uncomfortable for most people. |
| Q32 | surgery | In the 1960s, the famous underwater explorer Jacques Cousteau, for example, predicted that one day surgery could be used to equip humans with gills | Excerpt/Transcript Explanation: The transcript explains that in the 10-year period starting in 1960, a well-known explorer believed that medical operations would allow people to have gills like fish. Answer Explanation: The answer is surgery, which is a medical operation where a doctor cuts open a body to fix or change something. Reason For Correctness: The correct answer is surgery because the speaker mentions that in the 1960s, a famous explorer named Jacques Cousteau thought doctors could use medical operations (surgery) to give people gills so they could breathe underwater. In the notes, 'prediction' matches 'predicted' and 'humans would have gills added' matches 'equip humans with gills'. |
| Q33 | beetles | Scientists also looked at animals without gills which use bubbles of air underwater, notably beetles | Excerpt/Transcript Explanation: The transcript explains that when scientists were thinking of ideas for artificial gills, they studied animals that do not have gills. They were interested in how these animals use bubbles of air to stay underwater. The text says that 'beetles' are a main example of this behavior. Answer Explanation: The answer 'beetles' is a type of insect or bug. These specific bugs can stay underwater for a long time by using a small bubble of air to breathe. Reason For Correctness: The correct answer is 'beetles' because the speaker explains that scientists looked at animals that do not have gills to find ideas. She specifically highlights 'beetles' as insects that use bubbles of air to breathe while they are under the water. This matches the note about animals without gills and their use of bubbles. |
| Q34 | gas | You take a watertight box which is made of a material which is permeable to gas, that is, it allows it to pass through inwards and outwards | Excerpt/Transcript Explanation: The transcript explains that the box used for the gill is made of a special fabric or substance that lets gas go through it but keeps the water out. Answer Explanation: The answer "gas" refers to the air or oxygen that needs to move through the box's walls so a person can breathe. Reason For Correctness: The correct answer is supported by the speaker's description of how to build a simple artificial gill. To make one, you need a box that stays dry inside (watertight) but uses a special material. This material must be 'permeable,' which means it allows 'gas' to move in and out while blocking water. |
| Q35 | moving | But a crucial factor is that the diver has to keep the water moving so that water high in oxygen is always in contact with the gill, so he can’t really stay still | Excerpt/Transcript Explanation: The transcript explains that a very important part of using this device is that the water cannot stay still; it must continue to flow or circulate around the gill. Answer Explanation: The answer 'moving' refers to the action of the water staying in motion around the diver and the equipment. Reason For Correctness: The correct answer is 'moving' because the speaker mentions that for the artificial gill to work, the water must not be still. High-oxygen water needs to constantly touch the gill for the diver to breathe. Therefore, the diver must ensure the water stays in motion, or in other terms, keeps moving. This matches the point in the notes about what is 'important' for the diver and the water to do. |
| Q36 | surface area | And to maximize this contact, it’s necessary for your gill to have a big surface area | Excerpt/Transcript Explanation: The transcript says that to get the most oxygen from the water, it is required for the gill to have a large outside layer (surface area). Answer Explanation: The answer "surface area" refers to the total outside part or size of the gill's exterior that can touch the water. Reason For Correctness: The correct answer is "surface area" because the speaker explains that for the artificial gill to get enough oxygen, it needs to have as much contact with the water as possible. This is achieved by making the "surface area" — the outside part of the gill — very "big" or "large." |
| Q37 | tubes | Different gill designers have addressed this problem in different ways, but many choose to use a network or lattice arrangement of tiny tubes as part of their artificial gills | Excerpt/Transcript Explanation: The transcript explains that many people who design these gills use a system made of many very small pipes, or tubes, as a part of the machine. Answer Explanation: The answer "tubes" refers to the small, hollow pipes used to make the artificial gill work better. Reason For Correctness: The correct answer is "tubes" because the speaker explains how designers create artificial gills. She mentions that many designers choose to use a "network" or "lattice arrangement" of "tiny tubes." In the notes, the word "small" is a synonym for "tiny," which confirms that "tubes" is the specific part being described. |
| Q38 | pressure | So the basic idea works well, but the real limitation is that these simple gills don’t work as the diver descends to any great depth because the pressure builds and a whole different set of problems are caused by them | Excerpt/Transcript Explanation: The transcript states that the primary problem (the "real limitation") is that the gills stop working correctly in deep water because the force of the water (the pressure) gets higher. Answer Explanation: The answer "pressure" refers to the force of the water pushing against an object as it goes deeper underwater. Reason For Correctness: The correct answer is "pressure" because the speaker identifies a major problem with artificial gills. While they work well in shallow water, they fail when a diver goes deep because the force of the water increases, which creates many difficulties. The word "increased" in the notes matches the phrase "pressure builds" in the talk. |
| Q39 | submarines / a submarine | For example, the same technology might be used to provide oxygen for submarines, enabling them to stay submerged for months on end without resorting to potentially dangerous technologies such as nuclear power | Excerpt/Transcript Explanation: The transcript explains that the science used for the artificial gills can also be used to give oxygen to submarines. This helps them stay under the water for a long time. Answer Explanation: The answer is a type of large ship or boat that can travel deep under the ocean for a very long time. Reason For Correctness: The correct answer is identified because the speaker discusses other ways this technology could be used besides helping individual swimmers. Specifically, she mentions that it could provide air (oxygen) to people inside submarines. This would allow these underwater ships to stay deep in the sea for many months without using dangerous power sources like nuclear energy. The word 'provide' is a synonym for 'supplying' used in the notes. |
| Q40 | fuel | Another idea is to use oxygen derived from the water as energy for fuel cells. These could power machinery underwater, such as robotic devices | Excerpt/Transcript Explanation: The transcript explains that scientists have an idea to take oxygen from the water and use it as energy for fuel cells. These fuel cells can then provide power to operate machines under the water. Answer Explanation: The answer is the word 'fuel', which describes a specific type of cell that can create energy. Reason For Correctness: The correct answer is 'fuel' because the speaker mentions using 'oxygen derived from the water as energy for fuel cells' to 'power machinery underwater'. To power something means the same as 'driving' it here. This explains that these special cells are an alternative way to provide power to underwater machines. |
Transcript
Narrator: Test 2, section 4. You will hear a woman giving a talk at a popular science convention. She is describing research into artificial gills designed to enable humans to breathe underwater. Now you have some time to look at questions 31 to 40. Now listen and answer questions 31 to 40.
Presenter: In my talk today, I’ll be exploring the idea of artificial gills. I’ll start by introducing the concept, giving some background and so forth, and then I’ll go on to explain the technological applications, including a short, very simple experiment I conducted. Starting with the background. As everyone knows, all living creatures need oxygen to live. Mammals take in oxygen from the atmosphere by using their lungs, and fishes take oxygen from water by means of their gills, which of course in most fish are located either side of their head.
But human beings have always dreamt of being able to swim underwater like the fishes, breathing without the help of oxygen tanks. I don’t know whether any of you have done any scuba diving, but it’s a real pain having to use all that equipment. You need special training and it’s generally agreed that tanks are too heavy and big to enable most people to move and work comfortably underwater. So scientists are trying a different tack. Rather than humans carrying an oxygen supply as they go underwater, wouldn’t it be possible to extract oxygen in situ, that is, directly from the water while swimming?
In the 1960s, the famous underwater explorer Jacques Cousteau, for example, predicted that one day surgery could be used to equip humans with gills. He believed our lungs could be bypassed and we would learn to live underwater just as naturally as we live on land. But of course, most of us would prefer not to go to such extremes. I’ve been looking at some fairly simple technologies developed to extract oxygen from water. Ways to produce a simple, practical artificial gill, enabling humans to live and breathe in water without harm.
Now, how scientists and inventors went about this was to look at the way different animals handle this. Fairly obviously they looked at the way fishes breathe, but also how they move down and float up to the surface using inflatable sacs called swim bladders. Scientists also looked at animals without gills which use bubbles of air underwater, notably beetles. These insects contrive to stay underwater for long periods by breathing from this bubble which they hold under their wing cases.
By looking at these animal adaptations, inventors began to come up with their own artificial gills. Now, making a crude gill is actually rather easy, more straightforward than you’d think. You take a watertight box which is made of a material which is permeable to gas, that is, it allows it to pass through inwards and outwards. You then fill this with air, fix it to the diver’s face and go down underwater.
But a crucial factor is that the diver has to keep the water moving so that water high in oxygen is always in contact with the gill, so he can’t really stay still. And to maximize this contact, it’s necessary for your gill to have a big surface area. Different gill designers have addressed this problem in different ways, but many choose to use a network or lattice arrangement of tiny tubes as part of their artificial gills. Then the diver is able to breathe in and out, oxygen from the water passes through the outer walls of the gill and carbon dioxide is expelled. In a nutshell, that’s how the artificial gill works.
So, having read about these simple gill mechanisms, I decided to create my own. I followed the procedure I’ve just described and it worked pretty well when I tried it out in the swimming pool. I lasted underwater for nearly 40 minutes. However, I’ve read about other people breathing through their gill for several hours. So the basic idea works well, but the real limitation is that these simple gills don’t work as the diver descends to any great depth because the pressure builds and a whole different set of problems are caused by them.
Research is being done into how these problems might be overcome, but that’s another story which has to be a subject of another talk. Despite this serious limitation, many people have high hopes for the artificial gill and they think it might have applications beyond simply enabling an individual to stay underwater for a length of time. For example, the same technology might be used to provide oxygen for submarines, enabling them to stay submerged for months on end without resorting to potentially dangerous technologies such as nuclear power.
Another idea is to use oxygen derived from the water as energy for fuel cells. These could power machinery underwater, such as robotic devices. So in my view, this is an area of technology with great potential. Now, if anyone has any questions I’d be happy to answer. Yes, lady at the back.
Narrator: That is the end of section 4. You now have half a minute to check your answers. That is the end of the listening test. You now have 10 minutes to transfer your answers to the separate answer sheet.