Lesson video

Hello, my name's Mrs. Taylor, and I'm really pleased you can join me here today for our lesson.

Our lesson is "Proportions and scale: polymers and timbers", and this is part of the "Iterative design: nature" unit.

The outcome.

"I can determine and justify the size of my design." And we have five key words.

Specification, justification, proportion, dimensions, and scale.

There are three learning cycles in this lesson.

Design decisions, proportion and size, and scale.

Let's begin.

Design development is about constantly seeking ways to improve designs.

Once a designer has decided which design has the most potential, they will take this idea forward in development and eventually manufacture.

A designer can evaluate their design against their original design specification to help them decide which design to take forward and to justify their design decisions.

Let's have a check.

What can a designer evaluate their design against? Is it A, a design specification? B, an existing product? Or C, someone else's design ideas? Pause the video and have a go.

Fantastic.

Let's check.

That's right.

It's a design specification.

Well done.

The design specification describes what a design must have or do and is dictated by the research gathered.

To justify design decisions is to give a reason or explanation for the decisions.

Aisha has been developing ideas for the design opportunity of making the herbs accessible to wheelchair users.

This is the design specification Aisha wrote, following on from the research she carried out.

The subheading, the specification points, and the justification.

For example, user.

"The herb growing system must be suitable for wheelchair users," and the justification, "this is to ensure the user can use the product safely and efficiently." Materials.

"The materials must be waterproof and suitable for cleaning," and the justification, "the product will need to hold plants, which need watering and therefore must be waterproof." Function, "the system must allow herbs to be grown from seeds and also as plants.

Some users will want to grow herbs from seeds and others will buy plants." And the specification continued.

Aesthetics.

"The system must fit into a modern grey and silver kitchen theme, because the user has a modern grey and silver kitchen." The environment.

"The system must be sustainable.

My user is very conscious about the environment and would prefer not to cause any damage for future generations." And safety.

"The system must be stable and not topple over.

Some plants grow taller than others," is the justification.

Let's have a check.

What is the purpose of a design specification? Is it A, it provides step-by-step instructions for making the design? Or B, it describes what a design must have or do? Or C, it lists personal opinions about the design? Pause the video and have a go.

Wonderful.

Let's check.

That's right, it's B.

It describes what a design must have or do.

Well done.

These are Aisha's most recent design developments.

"I like the curvy shelves idea that goes onto the kitchen work surface, so I'm going to evaluate this against my design specification to see if it meets the points on it." Aisha has completed the table below of whether she thinks she has met the specification points or not met them.

She thinks that it has met the user specification that her herb growing system must be suitable for wheelchair users.

It has not met the specification point "the materials must be waterproof and suitable for cleaning." It has met function, it has not met aesthetics, not met the environment, and not met safety.

By evaluating her design against her design specification, Aisha has justified her decision to take the design forward.

She has also been able to review whether she still needs to make any changes or improvements to her design idea.

"I feel that although this design only meets two of my design specification points, it only needs a few developments to make it meet more of the design specification points.

I will take this idea forward to develop further, as it is one of my favourites." Let's have a quick check.

What is it called when an explanation or reason is given for design decisions? Is it A, estimation? B, observation? Or C, justification? Pause the video and have a go.

Let's check.

That's right, it's C, justification.

Well done.

Aisha has justified and explained why she thinks she has met and not met each point in her design specification.

The herb growing system must be suitable for wheelchair users.

"The design goes on the countertop, so it is more accessible from a wheelchair than the windowsill," is the justification.

The materials must be waterproof and suitable for cleaning, and the justification here is, "I am making my design out of polymer and timber, so we'll need to consider how to make the timber waterproof." The system must allow herbs to be grown from seeds and also as plants.

The justification, "The design can hold small potted seeds as well as larger plants." Evaluation of design ideas against the specification continued.

"The system must fit into a modern grey and silver kitchen theme." The justification, "It is a modern and clean lined design, but I need to consider the colour choices." The system must be sustainable.

"The product will be made out of timber, which is from a sustainable source, but the polymer is not." The system must be stable and not topple over.

The justification here is, "The design has a narrow base, which could result in toppling over." Task A.

Evaluate your chosen design against your design specification to help justify your decision.

And part two, consider how your design still needs to be improved.

You can lay it out similarly to the table below.

Pause the video and have a go.

Fantastic.

Let's have a look at some of the answers you may have come up with.

The specification point, "the herb growing system must be suitable for wheelchair users" was met, and "the design goes on the countertop, so it's far more accessible from a wheelchair than a windowsill," is the justification.

"The materials must be waterproof and suitable for cleaning" was not met.

"I am making my design out of polymer and timber, so we'll need to consider how to make the timber waterproof." The system must allow herbs to be grown from seeds and also as plants.

This was met.

The design can hold small potted seeds as well as larger plants.

Well done.

We now move on to proportion and size.

When designing, it is important to consider proportion, size, and scale of a design.

The proportion of a design refers to the balanced relationship between the different parts of the product.

Altering the proportions of a design can change it aesthetically as well as functionally and ergonomically.

Getting the right proportion and size of a product is important.

Hairbrush one has a very small handle, that will be uncomfortable and difficult to hold, and may result in repeatedly dropping the hairbrush when using it.

By changing the proportion of the handle and making it slightly longer for hairbrush two, it is a more balanced product, as well as being more comfortable and easy to hold and use.

Let's have a check.

What is proportion? A, a method for calculating the volume of objects? B, a type of measurement used only in geometry? Or C, a balanced relationship between different parts? Pause the video and have a go.

Let's check.

That's right.

It's C.

A balanced relationship between different parts.

Well done.

Aisha is worried that her design is too big for a kitchen countertop, and will take up too much space.

She's also worried it is not stable enough.

She has decided she needs to alter the proportions and the size of the product.

To do this, she will need to gather some external data to plan her sizes correctly.

What data do you think Aisha needs? Aisha has gathered the following data.

The depth of the average kitchen countertop is 600 to 650 millimetres.

The height of a one litre plant pot is 110 millimetres.

And the diameter of a one litre plant pot is 100 millimetres.

With this data, Aisha can now work out the sizes or dimensions of her product.

The dimensions are the sizes of objects or components.

Dimensions are calculated when designing based on research gathered, such as anthropometric and external data.

Dimensions are commonly represented in millimetres for greater accuracy when manufacturing.

Let's have a check.

What do dimensions describe? Is it A, the weight of an object? B, the size of an object? Or C, the colour of an object? Pause the video and have a go.

Well done.

Let's check.

That's right, it's the size of an object.

Aisha has altered the proportions and size of her product by having less shelves, making the base more stable, making it smaller, adding a hole for the pots to sit in.

And here we can see her developed design idea, including dimensions.

Task B.

Gather any external data you need to work out the proportions and size of your product.

And part two, sketch out your final design with any changes in proportions and include your dimensions in millimetres.

Pause the video.

Fantastic.

Let's have a look at some of the answers you may have come up with.

To gather any external data, you need to work out the proportions and size of the product.

Your answers could include the depth of the average kitchen countertop, the height of a one litre plant pot, and the diameter of a one litre plant pot.

Aisha's gathered this data to make sure the herbs fit into her planter and the planter fits into the planned location.

And part two, here we can see a two-dimensional drawing with dimensions.

"I have drawn a side view of my design in 2D, to show all the dimensions, including the size of the shelves.

I used the data I had gathered about the size of the plant pots to work out each shelf size, and this then helped me work out the overall size of the product.

I have also drawn the idea in 3D so that I can show all of the dimensions that couldn't be seen in the 2D sketch.

I have done my dimensions in millimetres, so I can manufacture it as accurately as possible." And now we move to the third learning cycle, scale.

When drawing final designs or making prototypes, designers often have to work to scale.

Scale is a ratio of full size.

Scale is used in design and prototyping to represent objects at a different size than their actual dimensions.

It helps designers create accurate drawings and prototypes that are easier to work with.

Let's have a check.

What would a designer use to represent objects a different size than their actual dimensions? Is it A, proportion? B, scale? Or C, dimension? Pause the video and have a go.

Wonderful.

Let's check.

That's right, it's scale.

There are standardised scales that are used by designers, engineers, and architects.

These are conventional ratios that are international so that everyone knows how to interpret scale drawings regardless of where they live in the world.

Some common standardised scales in product design are 1:1, 1:2, 2:1, and 1:5.

Designers have to choose the most appropriate scale to use when drawing or making prototypes.

A 1:2 scale means the drawing or model is half the size of the real object.

For example, if a car is four metres long in reality, a 1:2 scale model would be two metres long.

A 2:1 scale means the drawing or model is twice the size of the actual object.

If a phone is 10 centimetres in real life, a 2:1 scale drawing would show it as 20 centimetres.

Let's have a check.

If something is drawn five times smaller than it is, what scale would it be? A, 1:50? B, 5:1? Or C, 1:5? Pause the video and have a go.

Fantastic.

Let's check.

That's right, it's C, 1:5.

Well done.

Prototypes can also be made to scale.

It is not always appropriate to make a full-size prototype, and various factors need to be considered.

Manufacturing space, storage space, cost of materials, time to build, and sustainable use of materials.

Making a prototype in a smaller scale will still allow for the product to be manufactured and tested.

Before making a prototype, designers should ask themselves, do I need to make this prototype full size for it to be effective? Task C, consider and decide on the scale that you will make your final prototype.

Look at your final design and chosen dimensions to help you decide this.

And part two, explain and justify why you decided to use the scale you have.

Pause the video and have a go.

Well done.

Let's look at some of the answers you may have come up with.

"I have drawn my 2D sketch in 1:2 scale, meaning it is half the size of my actual product, so that it could fit onto an A4 piece of paper.

I have also decided to make my prototype 1:2 scale.

I have decided to use 1:2 scale for my final prototype as it will be more efficient with materials, but still suitable for testing." Here we have a summary of our learning today.

A designer can evaluate their design against their original design specification, to help them decide which design to take forward and to justify their design decisions.

The proportion of a design refers to the balanced relationship between different parts of a product.

Altering the proportions of a design can change it aesthetically, as well as functionally and ergonomically.

Scale is used in design and prototyping to represent objects at a different size than their actual dimensions.

Well done and thank you for joining me today.