Stage 3 Forces and Magnetism Comprehension Why We Need Magnetism - Comprehension.pdf

STAGE 3 Unit focus: Forces And Magnetism Text focus: Information Text Why We Need Magnetism Magnetism is really important to us as humans. Many modern inventions rely on magnets to ope...

STAGE 3 Unit focus: Forces And Magnetism Text focus: Information Text Why We Need Magnetism Magnetism is really important to us as humans. Many modern inventions rely on magnets to operate correctly. Even simple things like a fridge door use magnets to stay closed. Without them, your fridge wouldn’t be as efficient and food would spoil. Cars and many important buildings use magnets to lock the doors. These would all be very insecure without magnetism. It isn’t just modern inventions that mean humans needs magnetism. We have been relying on it since we first evolved. Space is filled with radiation and harmful particles. Most of these are emi ed from the sun and carried on solar winds. If these particles or radiation were to hit humans, they would wipe us out very quickly. Luckily, there is an area of the Earth’s atmosphere called the magnetosphere. The magnetosphere is created by the Earth’s magnetic field. It deflects most of these harmful particles and the radiation back into space. Sometimes, these particles become trapped in the atmosphere and react with the gases. When this happens, they produce lots of light. It is this that creates the auroras, which you might know as the Northern or Southern Lights. That’s not all. The Ancient Chinese and Greeks knew about magnetism from stones called “lodestones”. These rocks are highly magnetic, possibly after being struck by lightning. The Ancient Chinese realised that they could rub a metal needle against one and it would become magnetic itself, and always point to the north. They used this to help them navigate. This was the earliest form of compass. In 1820, a scientist named Hans Christian Oersted was experimenting with electricity. He passed a current through a wire and realised that it made a compass needle that he’d left lying around next to it move. This was the first time that anybody had realised electricity and magnetism were linked. Oersted’s discovery led to the invention of electromagnets. These are devices that use electricity to make a material magnetic. This was the first time that A magnets could be switched on and off. They are the technology behind ding ro Rea und all resources ©2022 Literacy Shed e um C u r r ic ul Th http://www.literacyshedplus.com many locks. When they are turned on, the locks are pulled into position by the magnet. When they are turned off, the lock is pulled back and can be opened. Animals make even more use of magnetism. Humans have been racing pigeons for centuries. They are released a long way from home, and the winner is the one that makes it back the quickest. For a long time we had no idea how they did this. Scientists now know that they can sense the Earth’s magnetic field and follow it. They can do this because they have small magnetic particles in their skulls. Salmon and bees can also use the Earth’s magnetic field to help them navigate. VOCABULARY FOCUS 1. If we “rely” on something, what does it mean? 2. If something is “efficient”, what does it mean? 3. Which part of the word magnetosphere tells the reader what shape it is? 4. When you navigate, you work out which way to __________ 5. Write an antonym for “linked” in this context. VIPERS QUESTIONS S How do electromagnets help to keep cars secure? R What type of stones did the Ancient Chinese use to magnetise needles? R Which animals have magnetic particles in their skull according to the text? I Why might Oersted have been considered lucky? P What else might we use electromagnets for? all resources ©2022 Literacy Shed http://www.literacyshedplus.com