Lesson Video: Applications of Radioactivity | Nagwa Lesson Video: Applications of Radioactivity | Nagwa

Lesson Video: Applications of Radioactivity Science

In this video, we will learn how to identify applications of nuclear radiation.

11:57

Video Transcript

In this video, we’re going to learn about the applications of radioactivity. Although radioactive materials are often dangerous, we’ll see that they also have lots of useful applications. These include agriculture, medicine, power generation, industry, and even space exploration. Before we look at these applications in more detail, let’s start with a reminder of what radioactivity is.

This is an atom. It consists of a nucleus, that’s this part here, surrounded by a number of electrons. Now, in some atoms, the nucleus is unstable, and when a nucleus is unstable, it can sometimes spontaneously change into a more stable form. This process of spontaneous change is called nuclear decay, and when a nucleus undergoes nuclear decay, it can emit particles and waves, which we call nuclear radiation. So nuclear radiation is emitted by unstable atomic nuclei when they undergo nuclear decay.

If a material contains unstable nuclei, we say that that material is radioactive. The radiation given off by radioactive materials transfers energy from its nuclei to its surroundings, and this energy makes nuclear radiation really useful. Perhaps the most obvious application of radioactivity is in nuclear power plants. Nuclear power plants use rods of highly radioactive material, such as uranium, as fuel. Because these materials are so radioactive, they transfer a lot of energy to their surroundings in a short time. In nuclear power plants, the energy released by the radioactive fuel is used to heat water. This causes the water to boil and turn into steam. This steam can then be used to turn a turbine, and this motion can then be used to generate electricity.

Throughout this process, nuclear energy in the fuel is transferred into thermal energy, which is ultimately transferred into electrical energy. It’s important to note that nuclear power plants produce radioactive waste. Over time, the rate at which nuclear fuel gives off energy decreases. And after a while, it no longer gives off enough energy to be useful for generating electricity. At this point, we can say that the nuclear fuel has decayed into nuclear waste. And once it reaches the state, it can be disposed of.

As well as generating electricity, radioactivity has applications in medicine, for example, in medical imaging. Special radioactive substances known as tracers can help us create images of the inside of the body. When a tracer is injected into the body, it gets naturally absorbed by a specific body parts, with different traces being absorbed by different parts of the body. Special equipment can then be used to monitor the radiation given off by the tracer once it’s being absorbed by a specific body part. And this enables a detailed picture to be built up of the body part in question.

Radioactivity can also be used for cancer treatment. Nuclear radiation can damage cells. So by carefully focusing radiation on specific areas in the body, it can be used to destroy cancer cells without damaging too many healthy body cells. This type of treatment is called radiotherapy.

The next application area we’ll look at is agriculture. Agriculture refers to the cultivation of plants and livestock for food and other uses. Insects are a big problem in agriculture. As well as damaging crops, they can spread diseases to livestock, lay their eggs in grain stockpiles, and generally cause problems for farmers. However, radiation can be used to kill or sterilize insects, controlling their population and protecting crops and livestock.

Radioactivity can also be used to change the properties of crops. This is done by exposing the seeds of crops to nuclear radiation. And this can cause changes to the DNA inside the seeds. These changes are called mutations, and they can change the way in which the seed grows, sometimes in a good way. And when good mutations occur, then farmers can grow the seeds from these mutated plants and pass their properties on to the next generation of crops.

Radioactivity also has many applications in industry. For example, it can be used to detect manufacturing defects in products such as this car door. This is done by placing of radioactive source on one side of the product and a sensitive radiation detector on the other side. Nuclear radiation which passes through the product is picked up by the detector, enabling images to be created of the inside of the product. This can show up welding defects and other flaws that may have occurred during manufacturing. Some industrial processes need very high temperatures in order to produce materials or products, and radioactive materials can be used to generate these high temperatures as radiation transfers nuclear energy into thermal energy.

The next application of radioactivity is in mining. Underground deposits of oil and gas are often mined so they can be used as fuel. Finding these deposits can often be difficult. However, radioactivity gives us a way of locating. The underground rocks that contain oil and gas deposits also contain radioactive elements. So by detecting the radiation given off by these rocks, radiation detectors can be used to detect oil and gas deposits.

The final application of radioactivity that we’re going to look at is in spacecraft. Radioactive materials can be used to generate the electricity used by spacecraft such as unmanned space probes. Spacecraft such as these use nuclear batteries. Nuclear batteries contain radioactive material. The nuclear radiation given off by this material transfers energy from its atomic nuclei to thermal energy, which is then used to generate electricity. So in terms of the energy transfers involved, nuclear batteries serve a similar purpose to nuclear power plants.

However, nuclear batteries use a very different mechanism to produce electricity. They don’t heat water into steam like a nuclear power plant does, and they also don’t contain any moving parts. Nuclear batteries are much less powerful than nuclear power plants, but they still provide much more energy than normal batteries, and they’re also very reliable. Okay, now that we’ve looked at some of the main applications of radioactivity, let’s have a go at some practice questions.

Which of the following statements correctly describes how the emission of nuclear radiation by decaying atomic nuclei can be used in electricity generation? (A) The energy of the particles and waves emitted as nuclear radiation can be transferred to thermal energy. Or (B) batteries that transfer the chemical energy of the emitted nuclear radiation to electrical energy can be made.

Let’s start by recalling that unstable atomic nuclei can sometimes undergo spontaneous changes known as nuclear decay. And when atomic nuclei decay, they emit particles and waves known as nuclear radiation. Materials which contain unstable nuclei are known as radioactive. And electricity generation is one of the main applications of radioactive materials. This question gives us two statements about how radioactive materials are used to generate electricity.

Now there are two main ways in which we can produce electricity using radioactive materials. The first is in nuclear power plants. In nuclear power plants, the energy of the nuclear radiation given off by radioactive materials is used to boil water. This process transfers energy from nuclear energy in the nuclei of atoms to thermal energy in the water. This causes the water to boil, turning it into steam, and the steam can then be used to turn turbines, which generate electricity.

The other method of using radioactivity to produce electricity is in nuclear batteries. Nuclear batteries contain small amounts of radioactive material. And the radiation given off by this material converts nuclear energy into thermal energy, which is then used to generate electricity. Nuclear batteries are different to nuclear power stations in that they don’t use water and they don’t have any moving parts. However, both nuclear batteries and nuclear power plants involve the transfer of nuclear energy to thermal energy via nuclear radiation. This means that statement (A) is correct. In both nuclear power plants and nuclear batteries, the energy of the particles and waves emitted as nuclear radiation is transferred to thermal energy which is then used to generate electricity.

But what about statement (B)? After all, we know that nuclear batteries use radiation to produce electricity. There’s actually just one word in this statement that makes it incorrect: chemical. Statement (B) says that we can make batteries which transfer the chemical energy of nuclear radiation to electrical energy, but this is incorrect since nuclear radiation does not have chemical energy. So we know that statement (B) is incorrect. And the correct answer is statement (A).

With that answered, let’s look at one more question.

Which of the following are current industrial uses of nuclear radiation? (A) Producing high temperatures, (B) making materials stronger, (C) finding defects in products, (D) forming very small objects from blocks of raw material.

Nuclear radiation, which is emitted by radioactive materials, has many industrial applications. These are applications where it’s used to develop or make products and materials. Let’s take a look at each of these possible answers in turn.

The first suggested industrial use for radiation is in producing high temperatures. We can recall that nuclear radiation transfers energy from the atomic nuclei of radioactive materials to their surroundings. We usually find that this energy is transferred to thermal energy in the surrounding environment. In other words, nuclear radiation can heat things up. For industrial processes that require high temperatures, radioactive materials are sometimes a good way of producing these high temperatures. So option (A) is a current industrial use of nuclear radiation.

Option (B) suggests that radiation can be used to make materials stronger. Now the energy carried by nuclear radiation means that it can change the structure of materials. However, we usually find that nuclear radiation damages or weakens materials. It’s not used to make materials stronger. Option (C) is finding defects in products. Certain types of radiation can pass through materials. So by directing radiation so that it passes through manufactured products and using a detector to pick up the radiation that emerges from the other side, images can be built up which show internal defects in the products, which would otherwise be invisible. So option (C) is another current industrial use of radiation.

Option (D) suggests that radiation can be used to form very small objects from blocks of raw material. Now, as we said, nuclear radiation can sometimes change the structures of materials. However, this can’t really be controlled. And forming very small objects from blocks of raw material is not a current industrial application of nuclear radiation.

With that question answered, let’s now summarize the key points that we’ve looked at in this video. Firstly, we’ve seen that radioactive materials contain unstable atomic nuclei which emit waves and particles known as nuclear radiation. This radiation has many uses, including generating electricity in nuclear power plants, medical uses such as diagnosing and treating illnesses, agricultural uses such as killing insects and producing useful mutations in crops, industrial uses such as finding defects in products and producing high temperatures, uses in mining such as locating underground oil and gas deposits, and generating electricity in spacecraft within nuclear batteries.

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