Grade 7 – Earth & Space Systems

Lesson Summary: Students will create an interactive simulation that demonstrates the particle theory of matter.

Curriculum Expectations: These expectations are intended to highlight the many ways in which this lesson could support

the curriculum. It is neither expected nor necessary for teachers to address all of these expectations at once. Teachers

are encouraged to select the most relevant expectations based on their unique context and intentions for the lesson.

Science & Technology

Mathematics

Language - Writing

Overall Expectations

A2. use coding in investigations and

to model concepts, and assess the

impact of coding and of emerging

technologies on everyday life and in

STEM related fields

A3. demonstrate an understanding of

the practical applications of science

and technology, and of contributions

to science and technology from

people with diverse lived experiences

E2. demonstrate an understanding of

heat as a form of energy that is

associated with the movement of

particles and is essential for many

natural processes within Earth’s

systems

Specific Expectations

A2.1 write and execute code in

investigations and when modelling

concepts, with a focus on planning

and designing programs

A2.2 identify and describe impacts of

coding and of emerging technologies,

such as artificial intelligence systems,

on everyday life, including skilled

trades

A3.3 analyse contributions to science

and technology from various

communities

E2.1 use particle theory to explain

how heat affects the motion of

particles in a solid, a liquid, and a gas

E2.3 use particle theory to explain the

effects of heat on volume in solids,

liquids, and gases, including during

changes of states of matter

Overall Expectations

C3. solve problems and create

computational representations of

mathematical situations using coding

concepts and skills

Specific Expectations

C3.1 solve problems and

create computational

representations of mathematical

situations by writing and executing

code, including code that

involves events influenced by a

defined count and/or subprogram

and other control structures.

C3.2 read and alter existing code,

including code that involves events

influenced by a defined count and/or

subprogram and other control

structures, and describe how changes

to the code affect the outcomes and

the efficiency of the code.

Overall Expectations

1. Generate, gather, and organize

ideas and information to write for an

intended purpose and audience

2. draft and revise their writing, using

a variety of informational, literary,

and graphic forms and stylistic

elements appropriate for the purpose

and audience;

Specific Expectations

1.1 identify the topic, purpose,

audience, and form for writing

1.2 generate ideas about a potential

topic, using a variety of strategies and

resources

1.3 gather information to support

ideas for writing in a variety of ways

and/or from a variety of sources

1.4 sort ideas and information for

their writing in a variety of ways

2.1 write short texts using a variety of

forms

2.3 use words and phrases that will

help convey their meaning as

specifically as possible

2.4 vary sentence structures and

maintain continuity by using joining

words (e.g., and, or) to combine

simple sentences and using words

that indicate time and sequence to

link sentences

3.4 use punctuation to help

communicate their intended

meaning, with a focus on the use of:

quotation marks to indicate direct

speech; commas to mark

grammatical boundaries within

sentences; capital letters and final

punctuation to mark the beginning

and end of sentences

3.8 produce pieces of published work

to meet identified criteria based on

the expectations related to content,

organization, style, use of

conventions, and use of presentation

strategies

Breaking Down the Coding Expectations in Science & Technology:

In the Grade 7 Science & Technology curriculum, there are two coding related expectations:

A2.1 write and execute code in investigations and when modelling concepts, with a focus on planning and

designing programs

A2.2 identify and describe impacts of coding and of emerging technologies, such as artificial intelligence

systems, on everyday life, including skilled trades

To paraphrase these expectations and express them in plainer language, students are being asked to:

• Prior to writing any code, students should plan the structure and logic of how their code will work

• show how coding impacts our lives

Both expectations will be addressed through the project.

Learning Goals: We are learning to write code to create an interactive simulator that demonstrates the particle theory

of matter

Success Criteria:

1. I can effectively plan a program

2. I can use conditionals to create interactions between different sprites

3. I can collect and use input from the user to change the outcome of my program

4. I can use variables to store data, including input from the user

5. I can effectively simulate the behaviour of particles in solid, liquid, and gas states

STEM Profile:

Particle theory helps us understand the interaction between temperature and

states of matter. One great example of this is refrigeration! Refrigerators work by

extracting heat and using it to evaporate a refrigerant (which is a fluid that

undergoes a repeated phase transition from a liquid to a gas and back again) which

then creates a cooling effect.

Someone who used this knowledge to his advantage was Frederick McKinley Jones,

a Black American inventor who created mobile refrigeration technology! Our ability

to eat food from across the country (and even across the world!) is completely

dependent on this technology. Even more, the portable cooling units he designed

were especially important during World War II, as they were used to transport

blood, medicine, and food for use at army hospitals and on open battlefields. Throughout his career he received more

than 61 patents, 40 of which had to do with refrigeration technology.

Like Frederick, we will be exploring the particle theory of matter so we can better understand how it shapes the world

around us and can allow us to create amazing new inventions of our own!

Minds On:

1. Students will have different experience levels when it comes to coding.

a) If students have never experienced coding before, please watch the “What is Coding?” video.

b) If students have experienced coding before, have a quick discussion in which students share their definition

of coding. Some responses to look for include:

i. Coding is the language that computers speak

ii. Coding is how we talk to computers or get computers to do what we want

iii. Coding is the instructions that we give to a computer

2. In small groups or as a whole class, brainstorm with students to generate ideas for their simulations that will show

how particles behave and interact in different states of matter. Some sample prompts include:

o What are the differences between pure substances and mixtures?

o What are different kinds of pure substances?

o What are different kinds of mixtures?

o What are the differences between elements and compounds?

Planning Our Project:

Introduce the idea of a flowchart, a type of diagram that shows the sequence of steps involved in performing an

algorithm, with specific symbols used to represent different control structures. The symbols used in a flowchart are:

• Oval - used to show the beginning and end of the program

• Parallelogram - used to represent input or output

• Rectangle - used to show processing (i.e., calculating or manipulating data)

• Diamond - used to show decisions (i.e., conditionals)

• Lines and arrows - used to connect the shapes to show the direction of the steps and to represent loops

• Text and labels - included with shapes, as necessary.

Since every student’s project will be different, so will the flowcharts that they create and the tools or technologies from

which they can choose to create their flowcharts (i.e., pen and paper, dedicated apps and websites for creating

flowcharts). A sample flowchart has been provided below to give a general sense of what the end product may look like.

Creating Our Project:

For this project, teachers may wish to assign a different state of matter to each student or group or to model the creation

of a simulation for one of the three states of matter and then invite students to create a simulation for one of the other

two states of matter of their choice. The sample code for solids, liquids and gases demonstrate how the project might

work for each of the three states of matter. For your reference, Scratch determines where to display sprites and controls

movement using a Cartesian coordinate system, with (0,0) being the center of the screen and it may be helpful to pre-

teach this concept, if it is one with which students are unfamiliar.

Option 1: Gas 
 
Part 1: Set Up 
 
1.  Create a relevant backdrop using the paint editor and add instructions to the backdrop using the text tool, if desired. 
2.  Add a sprite (i.e., the “ball” sprite can serve as a representation of the particles) and delete all the costumes for that 
sprite except for one. Use the paint bucket in the paint editor to set it to a solid colour to make interactions between 
each particle sprite easier to detect.  
3.  In the orange Variables menu, click “Make a Variable”.  
a.  Name the new variable “Temperature” and select the checkbox so that the variable appears on screen.  
b.  When the variable appears on the project preview screen, right click it and select Slider. This will allow the 
user to change the temperature in order to eventually impact the speed at which the particle sprites move.  
c.  You can reposition the variable on screen by clicking and dragging.  
 
Part 2: Basic Particle Settings 
 
1.  In the area for the particle sprite, add the When Green Flag Clicked event block.  
2.  Use the Set () To () block from the variables menu and change it to match with the name of your temperature 
variable. Setting it to a low number (i.e., 10) will make it so that when your code begins. the particles will already 
be in motion.   
3.  Use the Set Size To ()% block to resize the particle sprite (i.e., if using the default ball sprite from Scratch’s pre-
designed sprites, a size of 50%-75% works well).  
 
Part 3: Interactions Between Particles 
 
1.  Add a Forever loop from the control menu. Inside of the forever loop add the If on Edge, Bounce block to keep 
particles within the limits of the screen.  
2.  Still inside of the forever loop, add an If () Then block combined with a Touching Color ()? block from the sensing 
menu. Click on the pre-loaded colour and use the colour picker to select the exact shade of the particle sprite you 
have created to ensure 100% accuracy.  
3.  Inside of the If () Then block, add the following blocks, which will make it so that when two particles bump into each 
other, they turn in opposite directions and bounce away, creating the effect of an interaction: 
a.  Add the Turn () Degrees block and combine it with a Pick Random () to () block. Set the numbers to be 
between 150 – 210. The direction of the turn does not matter.  
b.  Add the Move () Steps block and set it to approximately 10. You can play around with the number to see 
what impact  that has  on your code,  but a  lower number (i.e.,  anywhere  from 5 to 15)  will make  the 
movement more realistic.  
 
Part 4: Respond to Temperature Changes 
 
1.  Outside of the If () Then block but still inside of the Forever loop from part 3, add a Move () Steps block and insert 
a () / () operator block.  
2.  Set the first blank space of the () / () block to the round block with your temperature variable name from the 
variables menu.  Set the second blank space to a value such as 10. This will make it so that as the temperature 
variable is increased or decreased with the slider, the movement of the particle sprites will speed up or slow down 
accordingly.  
 
Part 5: Create Many Particles 
 
1.  Each particle sprite will have the exact same code. As a result, you can just duplicate the sprite you have already 
created in order to make as many particles as you desire. To create a duplicate, right click on the icon of the sprite 
in the sprite pane and select “Duplicate.” Remember that if you make any changes in a particle sprite you will need 
to replicate those changes in all the other sprites.  
 
 
 
 
 

Option 2: Solid

Part 1: Set Up

1. Create a relevant backdrop using the paint editor and add instructions to the backdrop using the text tool, if desired.

2. Add a sprite (i.e., the “ball” sprite can serve as a representation of the particles) and delete all the costumes for that

sprite except for one. Use the paint bucket in the paint editor to set it to a solid colour to make interactions between

each particle sprite easier to detect.

3. Create two versions of this sprite with different colours so you can visually tell the difference and be sure to name

them clearly. For the remainder of this lesson, they will be referred to as the “red particle” and “black particle” (but

you can choose any colour).

4. In the orange Variables menu, click “Make a Variable”.

a. Name the new variable “Temperature” and select the checkbox so that the variable appears on screen.

b. When the variable appears on the project preview screen, right click it and select Slider. This will allow the

user to change the temperature in order to eventually impact the speed at which the particle sprites move.

c. You can reposition the variable on screen by clicking and dragging.

Part 2: Create the Container Sprite

1. Use the paint editor to design a sprite to be some kind of fully enclosed shape (i.e., a box). The shape should be an

outline only with no fill colour and the recommended pen size for the line thickness is approximately 10. No code

is needed in this sprite.

Part 3: Settings for Red Particle

1. In the area for the particle sprite, add the When Green Flag Clicked event block.

2. Use the Set () To () block from the variables menu and change it to match with the name of your temperature

variable. Setting it to a low number (i.e., 10) will make it so that when your code begins. the particles will already

be in motion.

3. Use the Set Size To ()% block to resize the particle sprite such that approximately 10 – 12 particles can fit within the

container sprite (i.e., if using the default ball sprite from Scratch’s pre-designed sprites, a size of 50%-75% works

well).

4. Use a Forever loop and add the following blocks inside to create the effect of the particles vibrating back and forth:

a. Add a Change X by () block combined with a () / () operator block and set the first blank space of th