:Powders
Trend Task
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Approach:  One to one Level: Year 8
872Kb
Focus: Properties of chemicals 
Resources: Blue pen; teaspoon of powders A, B, C, D, E, F in sample cups labelled A, B, C, D, E, F; instruction card; jug of water; red pen; 2 pairs of tweezers; 2 hand lenses; ruler; 12 ice block sticks; 6 sample cups; 2 eye droppers; team answer sheet; 6 teaspoons; 12 sheets A5 black paper

Questions/instructions:

Preparation: Before team arrives, put a teaspoon of each powder in the appropriately labelled sample cups.

In most homes you will find a lot of different kinds of powders that are used for various purposes. We usually know what the powders are by the labels on their packets or containers. Imagine what it would be like if a whole lot of powders were in the same kind of containers, and they didn’t have name labels.How could you tell them apart?

I have six containers with different powders that are found around most homes, but the labels don’t say what they are. They only say A, B, C, D, E, F.

I want your team to examine the properties of each substance, and to try to decide what it might be. You have hand lenses, tweezers, and water. You can use any methods except one: you must not taste them.


I also want your team to design a chart. On your chart I want you to try to show at least three properties of each substance, and to write down what you think the substance is. You will need to think carefully about how to set out the chart.

Here are your instructions.

Place instructions card in front of students, and read it to them. Allow up to 15 minutes for team activity.

To finish off, I would like you to show me your chart, and tell me what you found. Each person in the team is to have a turn at describing the results.
   



% responses
2003 ('99)
y8
Team work:
Involvement –
all students substantially involved
90 (84)
one student not substantially involved
9 (14)
Division of labour –
students worked together on all samples
39 (26)
informal division of samples within group
52 (70)
deliberate allocation to different students
9 (4)
Reporting results –

all had a turn
94 (92)
one did not have turn
3 (8)
two or more did not have turn
3 (0)
Style of investigating –




highly systematic
19 (7)
quite systematic
34 (33)
somewhat haphazard
39 (48)
very haphazard
8 (12)
produced information in chart form
81 (57)
Substance A –
identified as Ajax
17 (7)
2 or more relevant observations
51 (37)
1 relevant observation
19 (31)
Substance B –

identified as citric drink
99 (54)
2 or more relevant observations
69 (42)
1 relevant observation
13 (27)
Substance C –
identified as flour
75 (93)
2 or more relevant observations
55 (44)
1 relevant observation
18 (31)
Substance D –
identified as washing powder
95 (68)
2 or more relevant observations
61 (44)
1 relevant observation
12 (22)
Substance E –

identified as salt
46 (73)
2 or more relevant observations
55 (40)
1 relevant observation
14 (22)
Substance F –

identified as baking soda
38 (50)
2 or more relevant observations
44 (44)
1 relevant observation
24 (21)
Total score:




20–22
14 (4)
16–19
35 (22)
12–15
21 (20)
8–11
11 (30)
4–7
15 (22)
0–3
4 (2)
Commentary
There are surprising fluctuations between 1999 and 2003, with some substances handled much better in 1999 and others in 2003. Overall, performance was markedly higher in 2003 than in 1999.
 
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