Physics Energy Transformation II Some people need electronic devices called pacemakers to keep their hearts beating in a regular way. But what happens when the batteries go flat? A new pacemaker promises to solve this problem by capturing some of the energy generated by the heart itself. This is a print version of an interactive online lesson. To sign up for the real thing or for curriculum details about the lesson go to www.cosmoslessons.com Introduction: Energy Transformation II Imagine turning your body into a human generator that makes electricity. That’s what scientists have just done with a brand new invention that could make many people’s lives safer and easier. Our hearts never sleep. Whether you're sitting at your desk, walking to the bus, running a marathon or fast asleep, your heart is beating steadily, pumping blood around your body to deliver vital fuel to your cells. But for some people there's a problem. Their hearts sometimes miss a beat. For them the 褅ow of blood is uneven or slow, unable to keep all their organs operating eꀈciently. Fortunately, scientists long ago invented a device called a pacemaker. It's inserted under the skin beside the heart, with metal leads going into the heart itself. It sends regular electrical impulses to the heart muscles to make them contract, so the heart beats in time. This has saved the lives of many, many people, but there is a downside. The pacemaker has to get its power from somewhere, and it comes from batteries. As you know, batteries go 褅at and need changing – every 褅ve to 15 years for pacemakers, meaning another operation. But scientists have recently developed a pacemaker battery that never goes 褅at. It uses the power of the person’s own heart to recharge it. Each heartbeat produces a million times the energy that the tiny battery needs, so it is just a matter of transforming some of that energy into chemical energy in the battery. The device still has to go through rigorous testing, but if it passes, people with pacemakers will never have to have operations to change their batteries again. Read the full Cosmos Magazine article here. 1 Left: A typical pacemaker. Right: A self-powered pacemaker attached to a cow heart. Question 1 Imagine: One of your grandparents has to be 褅tted with a pacemaker and the hospital oㄆers them the opportunity to trial the new self-powered pacemakers. They ask you to help them decide – what advice would you oㄆer and why? 2 Gather: Energy Transformation II 0:00 / 3:51 Credit: All of the energy in the universe is... – George Zaidan and Charles Morton by TED-Ed (YouTube). 3 Question 1 Notes: Use this space to take notes for the video. Note: This is not a question and is optional, but we recommend taking notes – they will help you remember the main points of the video and also help if you need to come back to answer a question or review the lesson. Question 2 Question 3 Recall: Is it possible to remove energy from the things that Recall: We can tell diȾerent types of energy from one have it, so you have pure energy on its own? another by: Yes looking directly at the energy and seeing the diȾerences No gathering the energy in containers and I'm not sure measuring the diȾerences seeing what the diȾerent types of energy do measuring their diȾerent temperatures I'm not sure Question 4 Question 5 Recall: Can the universe ever lose or gain energy? Recall: Name the two types of energy important to chemists and brie尀y explain what they are. Yes, it can gain it but not lose it Yes, it can lose it but not gain it Yes, it can gain it and lose it, at diȾerent times No, the total amount of energy never changes I'm not sure 4 Question 6 Question 7 Recall: When chemical bonds break and reform, energy – Recall: Kinetic energy is the energy related to: as heat and light – is often released. This is possible because: storage molecules contain heat and light stored in stretching them moving chemical potential energy is stored in the way the atoms bond within molecules, and this is mass converted to heat and light bending chemical reactions take in energy from the surroundings and convert it into heat and light I'm not sure heat and light are created from nothing in the reactions I'm not sure Question 8 Describe: How are the temperature and kinetic energy of a group of molecules related? The video clip talks about two diȾerent ways that energy can change: 1. Energy transformation is when one form of energy changes into another form. An example from everyday life is electrical energy coming from a power plant transforming into light (and heat) energy in a light bulb. 2. Energy transfer is when the form of energy stays the same, but it moves from one object to another. For example, on a see-saw, the person at the high end has gravitational potential energy. As they go down this is transferred to the person on the other end. Question 9 Identify: The video includes examples of energy transformation and energy transfer. Identify one example of each and explain what makes it a transformation or transfer. Example Explanation Energy transformation Energy transfer 5 Process: Energy Transformation II 0:00 / 1:08 Credit: Energy Transfer and Eቈciency by Doodle Science (YouTube). NOTE: In the video he talks about energy transfers, when we'd call them transformations, because the type of energy is changing. Sankey diagrams can be used to show both transfers and transformations. Question 1 Notes: Use this space to take notes for the video. Note: This is not a question and is optional, but we recommend taking notes – they will help you remember the main points of the video and also help if you need to come back to answer a question or review the lesson. 6 Question 2 Explain: From what you've learnt from the above clip, deቈne what energy eቈciency is. Use the graphical comparison of light globes below to illustrate your deቈnition with an example. Graphical comparison of energy consumption of diቈerent types of light globes to produce the same brightness. Question 3 Calculate: Using the data in the graphical comparison above, calculate how many times more energy eቈcient a compact ቈuorescent globe is compared to an incandescent globe. Question 4 Infer: Work out the inputs and outputs of the energy transformations in the devices in the table below. Event Energy input Energy output Glowing light globe Electrical Kinetic and heat (depending on the toy it could also have light Wind up toy and sound) Boiling kettle Spinning top Kinetic Climbing stairs Gravitational potential and heat 7 Question 5 Label: The self-powered pacemaker takes a small fraction of kinetic energy from the heart to produce electrical energy. At the same time, the heart continues to transfer kinetic energy to your blood to pump it around your body. Use this information to label the Sankey diagram below. Double-click or tap in the spaces to enter text. Question 6 Draw: Use coloured squares, triangles and text to draw a Sankey diagram that represents the following energy transformations: A device is supplied with 100 joules of electrical energy and it produces 50 joules of kinetic energy, 20 joules of sound energy and 30 joules of heat energy. Note: Each horizontal band represents 10 joules of energy. 8 Project: Energy Transformation II Driving innovation Left: A child 吠lling water cans in the Kisenyi slums, Uganda. Right: An athlete running with a prosthetic leg. As well as the self-powered pacemakers described in the Cosmos Magazine article, John Rogers has designed a range of other inventions. These include skin patches to monitor wound healing, helmets for monitoring head damage to footballers, and soluble circuits to heat-sterilize wounds. Question 1 Imagine: You are a member of Rogers' team and have been asked to develop and present two new device ideas. One device must improve the standard of living in a third world country and the other should address an issue that is important to you. You will need to include: A mind map of initial ideas so that the design process is clear to the team. A storyboard that shows how each device will work. Hint: You may sketch this on paper and then upload a photograph of your sketch below. A list of the energy inputs and outputs of your devices. Hint: A Sankey diagram may help you represent these. 9 Career: Energy Transformation II Dr John Rogers isn’t just satisኸed with knowing how things work. He also wants to create new things that work in diㄆerent ways, like the self-powered pacemaker you read about in this lesson. John has always been fascinated with understanding the world around him. It’s not surprising – his dad has a PhD in physics, and his mum is a well-published poet who wrote many poems about nature and space. An appreciation of the natural world was just part of his childhood. After high school, John went to the University of Texas, where he decided to study both chemistry and physics. John says that chemistry taught him how to “make stuㄆ”, and physics taught him to understand what he made. Nearly 20 years later, John is still busy "making stuㄆ". He's especially interested in combining knowledge from a range of scienti褅c 褅elds to create new technologies that can help society. Not all of John’s time is spent innovating in the lab.