What will I use?

This task is about the physical properties of materials.

MATERIALS

Plastic Metal Wood

Paper Rope Glass

Finish the table by:

Picking the best material from the list to make each object.
Writing down why this material would be best to use.

The first one has been done for you.

Object	What is the best material to make this object?	Why is this the best material to use?
a) Stirring spoon	Wood	Wood takes a long time to heat up, so you won't burn your hand.
b) Window
c) Door key
d) Hammer head
e) Garden hose
f) Rubbish bags

Teaching and learning:

The science concept at the centre of this assessment is (physical) properties of materials, so answers that accurately identified the useful properties were accepted as appropriate. However, you may want to place emphasis on justifying their selection by asking students why the identified property (or properties) is important. This is modelled in the given answer for question a).
Encourage students to give multiple reasons, especially for the hose and rubbish bags. Often when we are choosing a material we have to weigh up the useful and less useful properties. Sometimes there are other non-science considerations, such as cost or availability. Although important, these are not physical properties of the material.

Diagnostic and formative information:

	Common response	Likely source of confusion
	(Bags) are easy to open and hold things. It is easy to carry. The water can get through (the hose).	Students are describing the structure of the item rather than the material it is made from.
b)	Glass keeps the cold out.	Students may think that glass is a good insulator, or only be considering keeping rain and wind out (which other building materials do as well). The fact that sunlight can pass through does have a warming effect, but heat passes to the outside easily as well.
f)	Plastic is disposable/ can be recycled.	A lot of plastic is not readily biodegradable. The fact that it takes a long time to break down is one of the negative aspects of plastic. There may be confusion between recycling and reusing.
f)	Plastic won't rip.	It doesn't rip as paper does when it is wet but will when there are sharp edges. Students are likely to be thinking about how paper loses its strength when wet. An example showing a correct understanding is: Plastic can hold the waste and wet waste won't leak.
e)	Select rope (for the hose)	Students are only considering a similar shape to a hose, rather than the material itself.

Some students described a property of the material that was valid but not the primary reason for choosing it over other materials. For example, some said glass was strong, which is true but not the main reason it is used for windows.

Next steps:

If students have difficulty in identifying properties of materials, a fun activity is to ask them to think of the silliest use they can for that material. They then describe why it would be ridiculous, and the teacher can help students to understand that these reasons relate to its properties. For example, concrete would not make a good parachute, because it is heavy. [Reference: Rosemary Feasey, Scicon Conference (Auckland), 2002.]

Encourage students to consider the range of properties a material has. For example, look at 2 types of rubbish bags (plastic and paper), compare a range of properties of each material by testing, and then make decisions about the best choice based on multiple reasons. Ask them to defend their choices by using evidence from all their tests. Some of the properties they might investigate are:

Strength
Strength when wet
Water resistance
Weight
Stretch
Biodegradability

Plan and carry out investigations into properties of materials. An investigative question stem could be, "What is the best material to use for …?"

Students often don't have the vocabulary to describe properties of materials. Explicit teaching of words such as absorbent, flexible, stretchy, waterproof, flammable, etc, will increase their ability to do so.

		Y6 (08/2006)
Student responses given as: Materials, Justification
a)	Wood Takes a long time to heat up, so won't burn your hand. (given)	answer provided
b)	Glass Transparent	very easy easy
c)	Metal Any one of rigid/ keeps its shape can be melted to mould into shape/ can be cut to shape it is hard/strong	very easy very easy
d)	Metal Any one of it is hard doesn't break easily it is heavy it is hard/strong	very easy easy
e)	Plastic Any one of it is flexible waterproof can be moulded to a tube shape	easy moderate
f)	Plastic Any one of flexible/stretchy light waterproof or Paper Any one of strong biodegradable	very easy moderate

You are here

Resource user links

What will I use?

What will I use?