Download KS2 Simulate Physical Systems Activity: Solar System Simulation

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KS2 Simulate Physical Systems Activity: Solar System Simulation
Recommended year group: Any key stage 2 (Science content from year 5)
Activity duration: 1 hour
Cross-curricular links: Science
Concepts and approaches
Simulation
Abstraction
Programming
Overview
In this activity pupils create a simulation of the Earth orbiting the Sun using Scratch.
Pupils think what the purpose of the simulation is and who the audience is, they then
decide what the most important aspects of the simulation will be, and in so doing
they are abstracting.
Pupil objectives
• I can design a simulation
• I can write a simulation program
• I can debug a simulation program
Introduction (15 mins in a large space)
• Ask pupils what we call it when we ‘model’ or act out a real world or imaginary
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situation or write the word simulation on the board and ask pupils what this word
means. Briefly discuss the word simulation.
In a large space give pupils 5 to 10 minutes to create a physical simulation of the
orbit of the Earth and the Sun. Do not give the pupils very much guidance at this
stage as to what must be included. What is important is for them to start to think
about what to include and exclude from their simulation.
Select one of two of the pupils’ physical simulations that showcase common
themes across the class. As a group discuss what aspects most groups included
and why.
Back in class, ask pupils what are the most important things that they know about
the Sun and Earth and their movements and jot their ideas down as a class list.
(Slide 2).
Pupils might suggest ideas such as:
• Sun is approximately round.
• Earth is approximately round.
• Earth is always approximately the same distance from the Sun.
• Earth rotates around the Sun.
• Earth spins.
• Entire Solar System including Sun moves.
• The Earth and Sun and distances are huge.
• There are other planet between the Earth and the Sun.
• The Moon orbits the Sun.
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•Explain you are going to be creating a simple simulation of the movement of the
Earth around the Sun using Scratch for younger pupils who are learning about
the Solar System. (It is suggested that you do not include the other planets or
Moon at this point.)
Explain that when we create simulations we must decide what is most important to include in our simulation.
Ask pupils what aspects you have listed are essential to the simulation.Can they
explain why these aspects are essential? What would happen if they weren’t
included? Perhaps put a tick next to these ideas.
Ask what aspects will they not include? Why? Perhaps put a cross next to these.
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Designing simulations (10 mins)
•If it is your normal practice introduce the learning objectives. (Slide 3).
•Explore the idea that simulations are not the same as the real thing, they are just
a representation, a model, we simplify reality. e.g. Sun is not really stationary.
Ensure that pupils understand that these simplified rules are the algorithms that
they will use to help them write their program.
When we simplify we are abstracting. You could introduce the word abstraction.
In KS3 pupils are required to design, use and evaluate abstractions, and some
teachers will use this term when describing the models that they create. Abstraction is a very important idea and key skill in computer science.
Ask pupils, in pairs, to create a design for their simulation as an annotated
sketch with rules (algorithms) they are going to include. (Slide 5). If needed,
model a class version first. (A design template is provided should you wish to
use it. Slide 4.)
Ask pupils to note things they are not representing in their model. This will help
them think about their abstraction, what they are including and what they are not
including. For example the scale is not correct. They are not showing the Earth
spinning, or the Sun moving.
Finally ask pupils to think what commands might be useful in their program of
the simulation and to jot these down under their design e.g. move, goto.
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Note: At this point you can either model the specific approach for programming
the orbit that is detailed below or your pupils can move straight on to creating the
simulation. This latter choice might suit classes who have had more experience
programming circular routes or more confident teachers who are comfortable supporting pupils exploring a range of approaches.
Modelling an approach to program an orbit (5 mins)
•Slide 6 shows as a series of images to help you explain the point towards, turn,
move approach, if needed.
Explain that there are many ways to program a sprite to achieve their design.
That is to make an object take a path around something. Explain you are going
to model one particular approach physically and this might help pupils work out
what commands they might use in their program. You will need space to do this
in class.
• Assign a pupil as the Sun and move them to the center of the space.
• Assign a pupil as the Earth and if you have a swivel chair, sit them on it.
• Move the Earth to a start position facing the Sun and explain they are pointing towards the Sun.
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• Turn the Earth 90 degrees anti clockwise
• Move the Earth a very short distance and ask pupils what will happen is we keep going forwards. (Earth will not be in orbit and will fly off.)
• Turn the Earth to point towards the Sun again. (Use the term ‘point to
wards’ as this is the same phrase as a Scratch command.)
• Again turn the Earth 90 degrees anti clockwise
• Move the Earth a short distance. (Use the word ‘turn’ and ‘move’ as you describe what you are doing as these terms match Scratch commands.)
Repeat the three steps a number of times until pupils recognise that they are creating
an orbit of the Sun.
• Point towards the Sun
• Turn 90 degrees anticlockwise
• Move a short distance
Ask children if they can remember what we call it when we do something over and
over again (repeat or loop).
Ask pupils to add these steps to their design, perhaps on the back, or besides their
diagram. (Slide 6 provides a reminder of these steps, if needed).
Ask them what they think this set of repeated steps might be (an algorithm).
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Main task: Creating the simulation (20 mins)
•If required, ask a pupil to quickly summarise and demonstrate the main features of
Scratch to the class, e.g. the areas of the programming environment, saving, the different palettes.
If your class has not used the point towards command before you could model how
to use it. However if they are confident to find out how it works, then allow them to
discover for themselves.
Explain to pupils that they will now be given 20 mins to work with their partner to program their simulations in Scratch.
Suggest to pupils they should break their problem down into parts (decompose). Support with ideas as needed e.g. First create a Sun sprite, then the Earth, then get the
Earth to move around the Sun.
To remain focused on the programming elements of this task encourage pupils to
import ready made sprite images rather than spending time on artwork.
If required, demonstrate how to import sprites, or ask a pupil to show how to do this.
Delete the Scratch sprite using right click ‘delete’, then right click on the folder icon to
upload a sprite from a file. Ensure that you have saved the sprite files in a folder accessible to pupils before the lesson.
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Click on the folder to upload a sprite from a file. (Scratch 2.0 and 1.4)
•Provide support to groups that require it during the main task. A ‘Scratch commands
help sheet’ has been provided which includes descriptions of commands which they
might use in their program.
Encourage pupils to experiment with how far the Earth is from the Sun and the value
used in the move command. They may notice that altering the distance moved within
their loop changes the apparent speed of the orbit, but if they increase it too much it
no longer looks like a circular orbit. Explain that an important feature of simulations is to be able to try different scenarios out.
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•If you see pupils doing work from which the rest of the class would benefit ask them to
share their design with the class and explain the code they have used to program it.
If pupils successfully create a simple simulation of the Earth rotating around the Sun,
ask them to undertake the Extension tasks.
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Mini-plenary: reminder to debug as they program
•Ask children why it is important to write a short section of
code, run it, write a little more
code, run it? To check it works as intended. Can pupils recall different approaches to
debugging which they’ve used in the past? The following points appear on slide 7 of the
presentation to support pupils in debugging the programs.
• Identify what the program should do?
• Observe what the program does do?
• Use your knowledge of the Scratch commands to work out where it went wrong.
• Fix it.
Mini-plenary: support and sharing
•Encourage pupils to question each other about how they have implemented their de-
signs in Scratch. If some pupils are struggling to get their programs to work, can other
groups offer advice – perhaps having worked through similar issues themselves?
Following this discussion, pupils should be given the opportunity to adapt, change and
finish programming their simulations.
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Plenary (10 mins)
(Slides 8 – 14 provide questions, examples, images and slide notes to support the plenary.)
•Revisit the objectives of the lesson and ask two of three pairs to demonstrate to the
class how they met the objectives by showing their designs and simulations.
•Discuss what was and was not included in the simulations and how simplification (abstraction) is used to create simulations.
•Discuss what simulations are and where they are used in the wider world and why. En-
sure pupils have understood that simulations help us to investigate dangerous, expensive, unlikely, very large, very small and imaginary scenarios. For example, training for
space missions, training airline pilots, creating building designs for earthquake regions,
researching nuclear energy, investigating changes in climate, creating computer games.
Encourage pupils to evaluate simulations perhaps considering.
• Purpose: Why make a simulation of this scenario, rather than do it in real life? Who is the simulation for? What is it used for?
• Abstraction: What is included or ignored? Why?
• Realism/Fidelity: Is it realistic? Does the same things always happen? How ‘life like’ is the simulation? Is the scenario limited? Why?
• Improvements: What could be changed to make the simulation more useful?
• Opportunity: Could you create a simulation like this? How would you do it?
A number of slides are provided with example simulations, or you may choose to look at
online simulations.
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Optional homework opportunity: For homework perhaps challenge pupils to think of
examples of simulations in the world around them?
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Differentiation
Support: A ‘Scratch commands help sheet’ has also been provided. An additional adult, if
available, may work with a small group of pupils to provide additional support. They may plan
a simulation as a group and work through implementing this in Scratch as a more guided
activity.
Stretch & Challenge: An ‘Extension sheet’ has been provided for pupils who finish the main
task. Examples of code that meet these challenges are shown in the ‘Extension Challenge
Notes’ document.
Assessment opportunities
•Informal, teacher assessment of progress during main task, class discussions and plenary.
•Formal, summative assessment of Scratch projects if required (note however these are
completed in pairs).
•Focus on: What should be included and ignored in the simulation (abstraction).What is a
simulation. What code has been used to create the simulation. Examples of simulation programs and their features in terms of Purpose, Abstraction, Realness/Fidelity, Improvements, Opportunity.
Teaching Notes
Example Simulations
Example simulations have been uploaded to the Barefoot Computing Scratch account in the
Solar System Simulation studio. These can be used to familiarise yourself with how pupils
programs may work.
There are a number of different approaches that can be used to program a sprite so it moves
around a point thereby creating an ‘orbit’’. The approach modelled in this activity is ‘point
towards, turn and move’ as shown below. However some teachers may choose to explore
other approaches to program an orbit, such as ‘planet offset’ or ‘draw a circle’, these approaches are outlined in the ‘Alternate approaches for programming an orbit’ document.
Point towards Sun, turn and move approach to programming a orbit.
To demonstrate this approach to programming an orbit you can use a rotating chair to physically act out pointing towards the Sun, then turn 90 degrees and moving forwards and repeating.
An example of code using a move point towards and turn.
If pupils use this approach it is very easy to add extra planets. The only change that is needed is to change the ‘go to’ variable that sets the initial start point of the planet.
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Concepts and approaches
Simulation
Simulations model real-world or imaginary situations. Simulations can represent
physical or real life scenarios such as an aircraft simulator or population growth.
In this activity pupils create a simple simulation as they model a real-world physical scenario that of the movement of the Earth around the Sun. They physically
simulate the movement and then create an annotated sketch of their model. This
is supplemented as they explore a particular approach to the design to create a
simple algorithm that they then use to help them write the code in Scratch.
Pupils go on to explore the scenario as they write the code, changing aspects of
it such as the distance of the Earth from the Sun. The opportunity to investigate a
scenario is an essential feature of simulations.
A mechanical model of a Solar System is also called an orrery. There are opportunities to look at the history of these early forms of a simulation. (See Slide 11 for an
image of a mechanical orrery.)
Abstraction
In this activity, as pupils model the Earth orbiting the Sun, they identify what is
most important to include in their simulation and consider what they are ignoring.
This process of simplifying the scenario is abstraction. Abstraction helps pupils
manage the complexity of our Solar System so that they can focus on just one
aspect of it and help them explore and learn about it.
Programming
In this activity pupils create a simulation in Scratch. In doing so they use their
knowledge of the Scratch programming language to implement the algorithm they
have created which describes how their simulation will work. Programming is the
process of implementing an algorithm as code.
Curriculum links
Computing: design, write and debug programs that accomplish specific goals,
including controlling or simulating physical systems
Science:
describe the movement of the Earth, and other planets, relative to the Sun in the
Solar System
describe the Sun, Earth and Moon as approximately spherical bodies
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Prior knowledge
Pupils should already have an understanding of algorithms and be familiar with the
programming concepts of: sequence, selection, repetition and variables using the
Scratch programming language.
Ideally, pupils should have already covered the science subject content related to
the movement of the Earth around the Sun. Links to a selection of web resources
related to this subject matter are shown below.
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•The Earth and space http://www.bbc.co.uk/education/topics/zkbbkqt
•Tours of our Solar System http://www.watchknowlearn.org/Category.
aspx?CategoryID=2813
•Planets and our Solar System http://www.nhm.ac.uk/nature-online/space/planets-solar-system/index.html
•http://www.solarsystemscope.com/ or Extreme planet makeover NASA simulation
Resources (downloadable from webpage)
•Space for pupils to act out a model of the movement of Earth around the Sun.
•A space in class to demonstrate a particular approach for programming the
movement of the Earth around the Sun
•A swivel chair (optional)!
•A projector to display Scratch and the activity presentation
•MIT’s Scratch 2.0 or Scratch 1.4 (Please refer to this guide).
•Whiteboards for simulation ideas, paper and pens for pupils’ designs or printed
simulation design template.
Scratch commands & extension task help sheet – up to one per pair of pupils, if
required.
Extension challenge notes – teacher notes on possible solutions.
Planet sprite files
Teacher examples of programs
• Scratch 2.0 online http://scratch.mit.edu/projects/31661996/
• Scratch 2.0 or 1.4 download
Teacher extension example – Adding the Moon.
• Scratch 2.0 online http://scratch.mit.edu/projects/37592666/
• Scratch 2.0 or 1.4 download
Alternate approaches for programming orbits – see teacher notes
Example annotated design
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Related activities
KS1 Introduction to algorithms
KS2 Scratch tinkering
KS2 Viking raid animation
KS2 Use selection in programs – maths quiz
KS2 Scoring system for maths quiz
KS2 Shapes and Crystal Flowers
Taking this further
http://www.timeaglestone.co.uk/computing-in-year-7orbit/
After the lesson: There are cross curricular opportunities to discuss simulations
used in science, history, geography, maths etc. For example, looking at how simulations have been used in the past, such as during World War I mechanical simulations of horses were used to help soldiers learn to ride.
In Science lessons: perhaps look at http://www.solarsystemscope.com/ or Extreme planet makeover NASA simulation or other online Solar System simulations.
Optional trips opportunity: There may also be opportunities to visit science
museums, local businesses or undertake virtual field trips to organisations with
simulators.
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