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

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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

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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.

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. A big part of his job is supervising his PhD students and teaching classes at the University of Illinois. There's also the business end of things – John has to try to sell his technologies to commercial companies and earn research grants to fund the research in his lab.

When he's not at work, John loves spending time with his family.

Question 1

Compose: Write a letter to Dr Rogers telling him about one of your inventions from the previous activity. Make sure to describe your design choices, and what problems you hope the device will solve.

Image Credits

Introduction: self-powered pacemaker, University of Illinois/University of Arizona; Project: 褅lling water, Uganda, Ute Grabowsky/Photothek via Getty Images; Career: Thompson-McClellan/University of Illinois. All other images: iStock and Adobe Stock.

10 Test: Energy Transformation II

Note: There may be more than one correct answer to the multiple-choice questions below.

Question 1 (1 mark) Question 2 (1 mark)

Which of the following statements about energy are true? The total amount of all types of energy in the universe:

You can hold a bunch of energy in your hands is increasing

You can't see energy but you can see what it is decreasing does changes up and down over time Diᦼerent types of energy are diᦼerent in how they make things behave stays the same You can tell diᦼerent types of energy from one I'm not sure another because they have diᦼerent temperatures.

I'm not sure

Question 3 (1 mark) Question 4 (1 mark)

Which of the following is not a type of energy? A stretched rubber band has:

Kinetic potential energy

Heat kinetic energy

Elastic no energy

Fire I'm not sure

Chemical

I'm not sure

11 Question 5 (1 mark) Question 6 (1 mark)

Chemical energy is a form of: Which of the following statements about chemical energy are true? heat It is present in molecules potential energy It is not a type of potential energy kinetic energy It can be converted into other types of energy gravitational energy such as heat and light

I'm not sure None of the above are true

I'm not sure

Question 7 (1 mark) Question 8 (1 mark)

Metal block A has temperature 25°C and metal block B has Air molecules are constantly bouncing oᦼ our skin. On a temperature 55°C. cold day:

The particles in A are moving faster than the our skin molecules have more kinetic energy particles in B than the air molecules

The particles in B are moving faster than the our skin molecules have less kinetic energy particles in A than the air molecules

The particles are moving the same amount in the skin and air molecules have the same both blocks, but B has more heat in it amounts of kinetic energy, but the skin has more heat in it than the air There is more kinetic energy in the particles in A I'm not sure

There is more kinetic energy in the particles in B

I'm not sure

Question 9 (1 mark) Question 10 (1 mark)

On a cold day: Which of the following involve energy transformations?

kinetic energy is transferred from the air to our A hot water bottle warming your feet skin Branches moving in the wind kinetic energy is transferred from our skin to the air A toy wind-up car racing across the ᦜoor skin energy is transformed into air energy A gas heater working

coldness in the air is transformed into coldness I'm not sure in the skin

I'm not sure

12 Question 11 (1 mark) Question 12 (1 mark)

We need energy to move, which we get from food. Which of the following statements are true about Sankey diagrams? Food contains kinetic energy, which our muscles are able to use They show all the energy types involved in an energy transformation Food contains electrical energy which makes our muscles work The thicker the arrow, the more energy it represents Food contains heat energy, which our bodies convert to kinetic energy The information in them can be used to calculate the eᦜciency of an energy Food contains chemical energy, which our transformation bodies convert to kinetic energy The input energy is normally shown on the left I'm not sure and the output energies on the right

I'm not sure

Question 13 (1 mark) Question 14 (1 mark)

A car engine transforms chemical energy stored in fuel A gas water heater transforms almost all of the chemical into kinetic, heat and sound energy. Given that the car’s energy in the gas into heat in the water. Therefore the intended task is to move around, which of these three water heater is very ineᦜcient. output energies could be considered as waste? True – heat is always a waste product of energy Kinetic transformations, so high heat production means low eᦜciency Heat True – the chemical energy in the gas should Sound be transferred to chemical energy in the water False – because in a water heater, heat is a None of the above useful form of output energy

I'm not sure False – high heat output is always a sign of energy eᦜciency

I'm not sure

Question 15 (1 mark) Question 16 (1 mark)

An electric drill converts 2000 J of electrical energy into: Which of the Sankey diagrams below is correct for the drill in the previous question? 400 J of kinetic energy in the turning of the drill bit

800 J of sound in the noise the drill makes A 800 J of heat B What is the energy eᦜciency of the drill? C 100% D 80% I'm not sure 40%

20%

I'm not sure

13 Question 17 (1 mark)

Learning goal 1: Explain the diᦼerence between an energy transfer and an energy transformation.

Question 18 (1 mark)

Learning goal 2: Describe what energy eᦜciency is. What is the formula to calculate it?

Question 19 (1 mark)

Learning goal 3: John, who likes cooking, is looking for an electric beater. He is considering two models and has found the following data for each:

Model A converts every 1000 J of electrical energy into 600 J of kinetic energy, 300 J of heat, and 100 J of sound Model B converts every 1500 J of electrical energy into 800 J of kinetic energy, 400 J of heat, and 300 J of sound

Which model is more eᦜcient? Show your calculations.

Total available marks: 19