L3 The Electromagnetic Spectrum PDF

Unit 7: Light and EEI Lesson 3 The Electromagnetic Spectrum LI: To understand that light is part of the Electromagnetic Spectrum. SC: I can understand that Visible light is part of a larger Electromagnetic spectrum that I cannot see. list the different kinds of...

Unit 7: Light and EEI Lesson 3 The Electromagnetic Spectrum LI: To understand that light is part of the Electromagnetic Spectrum. SC: I can understand that Visible light is part of a larger Electromagnetic spectrum that I cannot see. list the different kinds of electromagnetic radiation. understand different kinds of electromagnetic radiation and what they can do.  Warmup Watch a video: Note down any new words or ideas as you listen to it.  What is Electromagnetic Radiation? Electromagnetic radiation is a form of energy. It includes energy sources that we use in our day-to-day life. These include: Microwaves Light X-rays UV rays Radio waves Infrared waves  The Electromagnetic Spectrum The electromagnetic spectrum is the range of frequencies and wavelengths of electromagnetic energy. The largest waves are radio waves that are as tall as buildings and the smallest waves are gamma rays that are smaller than an atom.  Radio Waves Radio waves are most commonly used for communication as they are large and can travel great distances. A radio wave is generated by a transmitter and then detected by a receiver. Devices that use radio waves have an antenna to pick up the wave. The most common uses of radio waves are radio and television.  Microwaves Microwaves are generally between 1mm and 30cm. The most common use of microwaves are in microwave ovens. The wave causes the water molecules in the food to vibrate, this in turn heats the food. Like radio waves, microwaves are also used in communication but on a smaller scale. For example, microwaves are used in RADAR systems. When a microwave is pointed at an object, such as a car, the microwaves are reflected by the metal surface. The device then records the amount of time it takes for the wave to travel back to the receiver.  Infrared We cannot see infrared waves, we can sense the heat that they emit. utilised in various technologies such as night vision glasses, some heaters and infrared cameras, which can detect warmth. Additionally, infrared waves can be used for communication between nearby devices, for instance, TV remotes use infrared to change channels.  Visible Light Visible light is the only part of the electromagnetic spectrum that we can see with our eyes. When light interacts with an object, some of it is reflected. Our eyes in turn are able to detect this part of the wavelength and send a signal to our brains to process. The size of the wave is how the colour of objects are determined, red light has larger wavelengths whereas purple light has shorter wavelengths. When a light ray touches an object, only waves that are reflected from the object reach our eyes, consequently we only see that colour. The Visible Spectrum Light reaching us from the Sun is known as white light. Household lighting and torches are almost always designed to produce white light. By observing a rainbow, you can see that white light consists of many different colours. This set of colours is called the visible spectrum.  Dispersion The colours of the visible spectrum. are usually described as red, orange, yellow, green, blue, indigo and violet. (However, there is no sharp boundary between the colours. They merge into each other which could be separated by passing a narrow beam through a rainbow.) The separation of white light into the spectrum of colours is called dispersion.  Ultraviolet Light The waves of ultraviolet light, also known as UV light, are too small for humans to see, however, animals such as bees have the ability to see these waves. Most UV light is absorbed by the atmosphere and is dangerous to humans in large amounts. For example, overexposure to UV light can cause sunburn and mutate the DNA in skin cells, which can lead to the formation of skin cancers. Wearing sunscreen blocks the UV waves from touching the skin and prevent this from occurring. UV light is also used in sterilisation as it has the ability to kill bacteria.  X-Rays X-rays are so small that they can move through objects easily. The most common use of x-rays is in medical fields for viewing the inside of the body. An x-ray sensitive film is placed behind the patient and the x-rays are passed through the body. Only the shadows of the bones show up on the film as they are more dense than skin and tissue. This technique allows doctors to determine damage to the bones and also to find foreign objects.  Gamma Rays Gamma rays have the smallest wavelength known to man and have incredibly large amounts of energy. They are produced by neutron stars and supernova explosions, while on Earth they are produced by nuclear explosions and lightning. Gamma rays are incredibly dangerous to human life as they are small enough to damage DNA.  Independent Tasks Beginning – Worksheet Q 1 Consolidating – Worksheet Q 2 Extending – Worksheet Q3 L3: The Electromagnetic Spectrum Worksheet Reflection/exit pass List 1 kind of Electromagnetic Radiation and a brief definition. It must be different to the 2 people in front of you.