Introduction to the topic

Materials are all around us as this is what objects in our world are made of. The clothing you are wearing and the room you are in are all made of materials and these material have different properties. Some properties are decorative such as colour and other properties are structural such as strength and hardness.

Activity: Today we are going to conduct a stress test on some common materials to see how strong they really are. This activity will work best working in pairs or groups of three. The following table is available here as an A4 page which you can print if required.

• Place each side of the material on two tables so that there is a gap in between.
• Pull down on each material using a spring scale placed in the middle of the material.
• Record the distance between the two tables in the 'Distance between' column measured in centimetres.
• Record the force at which the material broke in the 'Force to break' column measured in Newtons.
• If the material bent but would not break, then write "Bent" but still record the distance.
• Compare your findings with other students during this investigation and discuss any differences.

Of the materials that we tested today, were there any that you found did not break? Which ones? Did every group find this same thing? What did these materials have in common? What material did you find broke the most easily? If there were any differences, what do you think caused this? Let’s break it down – what distance did each of the groups that got different results choose? Likely you found that the closer the distance apart the tables were, the harder it was to break the specific material.

Now we are going to watch a video (7:01) about The Three Little Pigs where the importance of the strength of different materials is very clear. You probably all know this story, and now that we have tested our materials, we can see how essential it is to choose the correct materials for the appropriate uses!

Choosing suitable materials

Types and uses of materials

The following video (3:58) provides a great introduction to materials and their properties.

So, from watching the video, who can remember some of the different types of materials that were identified?

When objects are made, there is some thought that goes into what to use to give each object the shape and texture that best fits its use. For example, we would not make a blanket out of metal, because that would not be very comfortable to use.

Introduction to material properties

Material and toys. Each student can make a table of their favourite toys including some information about the materials involved. 

We are going to use our new knowledge of materials to build a puppet friend. Before we start, let’s think of some key features we want in our new friend, and what materials will help us achieve this. Maybe you want your character to be waterproof, or a knight in shining armour, or a superhero. Whatever features you decide will be right for your character, you need to decide what materials will make it achievable. Some material options are listed below.

• Paper bags
• Fabric 
• Googly eyes 
• Cotton balls 
• Aluminium foil  
• Fabric squares 
• Cling wrap

Materials vs. Objects vs. Fasteners
In the past two weeks we have learned all about the different types of materials and how to select which is best to use for each creation. But does anyone know – what is the name of the mechanism used to keep two or more materials together?
A FASTENER! Can anyone think of some examples of fasteners?

Recycling

We are going to begin today by watching this snippet from a Curious George episode. As we watch, pay special attention to all the different creations George makes out of plastic. We will discuss them after the video (4:17)!

Introduction to the design cycle

Processes v cycles

TMI

Think Make Improve

There are several variations of the design process but the one adopted here is TMI (Think, Make, Improve) first proposed by Martinez and Stager in 2013. “Reducing the process to three steps minimises talking and maximises doing” (Martinez & Stager, 2019, p. 54). TMI is an example of the maxim to “make everything as simple as possible but not simpler” which is widely attributed to Albert Einstein. Children are unlikely to forget the three steps in TMI in contrast to existing design models which “may be too wordy or abstract for young learners” (Martinez & Stager, 2019, p. 54).

The following video (6:48) is of Jeff Paulson reading The most magnificent thing by Ashley Spires. It is a light-hearted reminder that design involves multiple attempts and iterations.

More about plastic

As the video mentions, plastic is very durable and has a long-lasting life, which can be both a good and bad thing. This next video will show us a bit more background on plastic and why recycling it when you’re finished is essential.

Activity:
Plastic is a very useful material thanks to its versatile properties (e.g., it can be hard or soft, transparent or opaque, etc.), and its waterproofness. The waterproof property of plastic is what we are going to apply to our activity today.

Everyone is going to receive a plastic bottle, and your task is to cut it into a planter shape. You can decorate the planter however you like, but make sure you cut tiny holes in the bottom of the planter and create a plate-like shape to attach to the bottom of the planter to catch the water that seeps through the holes.

Flexibility

Flexibility can be an important property to consider in engineering to avoid breaking. In addition to large movements caused by natural disasters such as earthquakes, there are also daily factors which need to be accounted for such as contraction and expansion through changes in temperature and movement caused by wind.

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