A note to teachers Activity Description In this activity your pupils will review their experiments from the Solar System Science workshop and discuss their results and conclusions in more detail. Pupils will need the worksheets from the Solar System Science workshop which contain their results. The presentation is designed to be teacher-led, with opportunities for group discussion and/or individual work. Learning Objectives • To compare results with other groups in the class • To further link the experiments with the real Solar System Please note… Before you begin this activity, we recommend you familiarise yourself with it. This presentation contains differentiated elements . You are welcome to remove parts, edit or add to this presentation as you see fit, to tailor it to your class. We hope your class finds this activity interesting and useful. Should you have any feedback, please do not hesitate to send it to us. Thanks! - The Jodrell Bank education team Solar System Science After-workshop activity Image credit: NASA/JPL What you did... In the Solar System Science workshop you completed four experiments about different aspects of our Solar System. Image credit: NASA/JPL What we are going to do now... In this activity, we’re going to check our results by comparing them with other groups. Scientists do this all the time, to make sure their results really show what they think they do. We will also learn more about the Solar System as we go! Starter: What’s in the Solar System? 1. stars thethe Solar System have? 2. How 3. 4. 5. Anything Howmany many else? dwarf planets asteroids? Ourdoes Solar planets? in System! Solar System? 1 Star (the Sun) 1 Dwarf planet in here 8 Planets Billions of comets out there? You live here! Plus loads of meteoroids! Click on a hyperlink to find out more! Over 100 million asteroids 4 Dwarf planets here Image credit: NASA (not to scale) But where did the Solar System come from? Watch this video to find out how the Solar System formed… You must be connected to the internet for this video to play. If it is still not playing, click the link below or copy & paste the address into your web browser: http://youtu.be/RT4OO0TFLHw 1: Gravity Experiment • Before we look at your results, let’s think about gravity a little bit… • How would you describe what gravity is? Image credit: NASA Gravity • Gravity is the force that keeps us on the Earth. • Is gravity a pushing force or a pulling force? Gravity is a pulling force that pulls us towards the centre of the Earth. In what direction would gravity be pulling if you were standing at the South pole? Image credit: NASA Image credit: NASA This rocket is leaving Earth. Which answer correctly describes Earth’s gravity acting on the rocket: A, B or C? The answer is... A B Gravity gets weaker the further you get away from a planet, but it does extend out into space! C: Neither! (there’s no gravity in space) • It’s gravity pulling downwards that causes things to have weight. • Weight is a force. • In science what do we measure forces in? In science we measure forces (including weight) in units called Newtons Image credit: NASA Gravity experiment: Taking our readings • In task 1 you measured the weight of six pots using force meters. • If your group had two force meters, you may have needed to choose the correct one to take your readings… Can you think why this is the wrong force meter to use? This force meter reads 1 Newton – the maximum number on the scale This force meter is at its maximum. This means this pot could weigh 1 Newton or it could weigh anything over 1 Newton. It’s impossible to tell! When measuring things, it’s important to choose the right scale! Gravity experiment: Task 1 • Let’s now compare the different groups’ readings from task 1. • Click here to download our Excel file to help. • Questions to consider: – Did every group get exactly the same results? – If not, can you think of any reasons that might make the results different? Scientists always check their results with other scientists to make sure their results agree. Gravity experiment: Task 2 • We then imagined each pot contained the same amount of stuff, but that each one was on a different place in the Solar System. • This caused the pots to have different weights. • Can you remember why being somewhere else in the Solar System makes weight different? • On different planets, the strength of gravity is different. • This means on another planet an object is pulled downwards by a different amount, compared to when it was on Earth. • This means the object will have a different weight. Can of beans on Earth... 4 Newtons Same can of beans on Mars... 1.6 Newtons Image credits: NASA Gravity experiment: Task 2 • In task 2, you matched up each pot with where you thought it was, based on the strength of gravity on those different places. • If you didn’t finish task 2, you can complete it now (so long as you have your results from task 1). Here’s the strength of gravity on the six different places we looked at: Venus Earth Moon Mars 9 10 2 4 Jupiter Neptune 26 11 Task 2 answers... Pot Place A Venus B Earth C Moon D Mars E Jupiter F Neptune • How many agree and disagree? • If you didn’t get it right, is it because you measured a different weight in task 1, or was it a mistake in task 2? 2: Sunlight Experiment Sunlight shines throughout the Solar System, providing planets with light and heat. Image credit: International Astronomical Union (not to scale) Sunlight experiment: Task 1 • In this experiment, we imagined the bulb on the table was the Sun. You measured the brightness of the light from the ‘Sun’ at different distances away from it, using a light meter. • In task 1 you were asked to make a prediction. • What did you predict would happen to the amount of light as you got further from the Sun? Scientists always make a prediction before they do an experiment. It’s not about getting it right or wrong – it’s about making sure they’re testing the right thing! Sunlight experiment: Task 2 Amount of light • Draw a line graph of your results from task 2. The axes below may help you… Graphs help scientists see patterns in their results. Mark the points on your graph, then draw a curve between them! Distance (centimetres) Teachers: You can create a whole class graph using the Excel file! Just click tab 2: Sunlight and enter the data. Sunlight experiment: Task 3 • Does your graph show the brightness going up, going down or staying the same? • Did all groups find the same pattern? • Does your pattern agree with your prediction? Remember – in science, if your results don’t agree with your prediction, it doesn’t mean you’ve gotten it wrong! It just means you found something unexpected! Sunlight experiment: Extra Task • If you had time to do the extra task, you took an extra set of readings and compared them to your first ones. • If you did this, were your second readings exactly the same as your first? • Can you think of a reason why they might be different? In science, results are very rarely exactly the same because experiments are never perfect. That’s why experiments are repeated over and over! More about Sunlight… • Let’s now think about the sunshine in the real Solar System… • Sunlight falling on a planet provides it with heat. • Look at your graph of results, where do you think the hottest planet would be? Where do you think the coldest planet would be? Image credit: NASA/SDO (AIA) The temperature of the planets • This graph shows the average temperature of the planets, compared to how far away they are from the Sun. • Is it the same shape as your graph? • Which is the hottest planet? Which is the coldest planet? • Are these the planets you expected? The temperature of the planets • Here are the average temperatures of the planets in table form… Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune 167˚C 462˚C 16˚ -63˚C -145˚C -168˚C -224˚C -200˚C • Which planet is hottest? Which is coldest? • Are these the planets you expected? • Venus is the hottest planet – even though Mercury is the closest to the Sun! • Uranus is the coldest planet – even though Neptune is the furthest from the Sun! • Let’s find out why… Mercury Mercury is the closest planet to the Sun. This means it gets blasted by the Sun’s light and heat. The temperature on the day-time side can go up to 427˚C! However, Mercury has no atmosphere (no air). Atmosphere around a planet acts like a duvet – trapping in heat. At night, with no atmosphere to keep Mercury’s heat in, the heat zips off into space and Mercury cools down very quickly. On the dark, night-time side of Mercury, temperatures can drop down to a very chilly -173˚C! This makes the average temperature on Mercury about 167˚C. Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington Venus Venus is the second closest planet to the Sun, but it is the hottest. This is because Venus has loads of atmosphere! Venus’ atmosphere is 93 times thicker than Earth’s! The whole planet is covered in a thick layer of clouds – you can’t even see the surface! Venus’ atmosphere is mostly made of carbon dioxide, which is a greenhouse gas – very good at trapping in heat! (the carbon dioxide didn’t come from cars and factories on Venus, but from lots of volcanoes!) All this means that Venus warms up from the heat of the Sun, and stays hot! The temperature on Venus is an even 462˚C! Image Credit: NASA/JPL Uranus and Neptune Uranus is the seventh planet from the Sun, but it is the coldest at -224˚C. Neptune is slightly warmer at -200˚C. This is because, although Neptune gets less light and heat from the Sun, Neptune generates more heat in its core. Neptune actually gives off 2.6 times more heat than it receives from the Sun. At the moment, we don’t know what’s causing that heat! Image Credits: NASA, ESA, and M. Showalter (SETI Institute); NASA/JPL The solar system and water… • Look again at the average temperatures of the planets in the Solar System… Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune 167˚C 462˚C 16˚ -63˚C -145˚C -168˚C -224˚C -200˚C • On what planet could you find liquid water? The only planet in the Solar System where you can have liquid water is Earth. Any closer to the Sun and water boils. Any further away, and it freezes. The area around a star where the temperature is right for liquid water is called the Habitable Zone (or the “Goldilocks Zone” – can you think why it’s called that?). In the habitable zone, living things might be able to survive! (all the living things we know of need liquid water to live) Scientists are currently using telescopes to look for other planets in the habitable zones around other stars. Watch this video about one such planet found in 2014… You must be connected to the internet for this video to play. If it is still not playing, click the link below or copy & paste the address into your web browser: http://youtu.be/RlidbLyDnPs 3: Cratering experiment There are lots of places in the Solar System where you can find craters, such as the Moon, Mars, Mercury and even the Earth. This is meteor crater in Arizona, USA! Can you remember what causes craters? Image credit: Shane.torgerson Craters are caused by bits of rock and metal falling from space and crashing into the ground. This NASA animation shows this happening on the Moon… You must be connected to the internet for this video to play. If it is still not playing, click the link below or copy & paste the address into your web browser: http://youtu.be/mDNXAicVHZA When these bits of rock and metal fall to Earth, we can sometimes see them as shooting stars… You must be connected to the internet for this video to play. If it is still not playing, click the link below or copy & paste the address into your web browser: http://youtu.be/v-DmkH7udc4 Should we be worried? • Another name for a shooting star (something falling from space) is a meteor. • Most meteors are completely harmless. They are usually very small (the size of a grain of rice perhaps) and they get so hot as they fall to Earth, that most are completely destroyed! • If any part of the meteor does survive and crashes to the ground, this is called a meteorite. • Most meteorites are also harmless – they usually fall in the sea, or places where there aren’t people. Earth versus Moon • Can you think why the Moon has loads more craters than the Earth, even though we get hit just as often? Image credits: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC and Dave Tyler Earth versus Moon There are three reasons why the Moon has more craters than the Earth… 1. The Moon has no air. This means there’s no friction to burn up the smaller meteors – every meteor hits the ground on the Moon! 2. The Moon has no sea. About 70% of the Earth’s surface is covered by water. Any meteorites landing here wouldn’t make a crater! 3. The Moon has no weathering. When craters are made on the Earth, over a long period of time wind, rain, plants and animals will slowly wear the crater away. Cratering experiment: Task 1 • In this experiment, you dropped balls into a container of sand and measured the size of the crater which was created. We imagined the balls were meteorites and the sand was the surface of a planet. • In task 1 you were asked to choose a small, medium or large ball. Cratering experiment: Task 2 • In task 2 (a) you were asked to make a prediction. • Which height did you predict would leave the biggest crater? • Why did you think that? Remember: predictions are not about getting it right or wrong – they’re to make sure you’re testing the right thing! • Task 2 (b) asked: Why must you keep using the same ball during your test? • The size of the ball might also affect the size of the crater. We only want to test how the height changes the crater size. So, we change only the height and keep everything else the same. This keeps it a fair test. Cratering experiment: Task 3 • Let’s now compare the different groups’ readings from task 3. • You can again use the Excel file to help. Just click tab 3: Cratering and enter the results. Remember: Scientists always check their results with other scientists to make sure their results agree. Cratering experiment: Task 4 • Which height left the biggest crater for your group? • Did all groups find the same thing? • If not – what might have caused a difference? • Looking at the class average results, do all three of the balls show the same pattern? • Do your results agree with your prediction? Remember – if your results don’t agree with your prediction, it doesn’t mean you’ve gotten it wrong! It just means you found something unexpected! 4: Meteorite experiment When meteors land they are meteorites. These are very different from Earth rocks… Where do meteorites come from? • Meteors and meteorites start life floating in space as meteoroids. • Meteoroids usually come from when asteroids crash together, sending out tiny pieces into space. • Meteoroids have been floating in space for a long time – usually billions of years! • This makes them much older and very different from any of the rocks from the Earth… Earth rocks • Rocks on Earth are formed in lots of different ways. • One of the ways is for lava (from volcanoes) to cool down and solidify into rocks. • Did you know that lava is just hot, melted rock? Like ice is to water, rock is to lava! • Lava can make lots of different types of rock, depending on how quickly it cools down. Image credit: Jason Bott, Christopher Berger, Pete Garza Meteorite experiment: Task 1 • In this experiment, you had five rocks. Following a flow chart, you performed a series of tests. The results of the tests allowed you to identify the rocks. 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Venus. but might from ismagnetised, where they got ithot and be burnt as being struck byEarth! lightning! they fell to Congratulations! • We have come to the end of our experiments into the Solar System! • We hoped you enjoyed your experiments, plus we hope you learnt a few new things! Thanks, from everyone at Jodrell Bank!