Food in the sun
| Y4 (11/2007) | ||
| a) |
Any or a combination of:
|
The most common response was change of state,
e.g., it would melt.
|
| b) |
Any or a combination of:
|
The most common response was change of quality,
e.g., it would taste like spew.
|
| c) |
Any or a combination of:
|
The most common response was change of state,
e.g., it will disappear.
|
| d) |
Any or a combination of:
|
The most common response was change of quality,
e.g., the sandwich will get dry.
|
Why is learning about change important?
Change and constancy has been described as one of the unifying ideas of science. "Descriptions of change are important for predicting what will happen; analysis of change is essential for understanding what is going on, as well as for predicting what will happen; and control of change is essential for the design of technological systems" (American Association for the Advancement of Science, 1990).
For all four examples, it was very easy for the trial students to describe one change. However, very few attempted to describe more than one change (less than 20% for any of the questions). One example was for milk: it would go warm (describing temperature) and mouldy (change of quality).
| Student response | Likely misconception |
| The milk would "dry up" or "disappear". | They are likely to be thinking about evaporation, but may not have considered that the carton is closed, so could not escape. |
| Nothing (would happen to the water) | Reliance on the appearance only. |
Extending understanding of changes of substances and materials
Ask the class to make a list of all the sorts of changes that they think could happen (to a glass of water, etc.) Carry out investigations and encourage students to describe all the changes they notice. Filling in a chart they have designed with the teacher may help them to identify multiple changes.
- Has it got warmer or cooler?
- Has the texture changed?
- What do you notice about the smell?
- Has the colour changed?
- Has the volume changed? Is there less or more?
- Encourage students to use senses other than just sight.
SAFETY NOTE: Tasting is generally discouraged in science, particularly in this context where food is likely to deteriorate. Inhaling spores from fungi causes an allergic reaction in some people, so discourage students from sniffing anything mouldy.
Document changes over regular intervals. Which changes occur quickly, which ones take more time?
Document changes over regular intervals. Which changes occur quickly, which ones take more time?
Communicating in science
Develop word banks with students to extend their vocabulary for describing the changes they notice. This is particularly important for ESOL students or those with limited vocabulary.
Discuss how labels can add information to pictures and diagrams. Explore examples of labelling of diagrams in science texts for children. A potential resource available in schools is the Connected series. Encourage students to add labels to their own diagrams.
- What can't you tell from your diagram?
- Would a label help to add this information?
- How does the label help other people read the diagram?
For other ARB resources about changes in food use the keyword "food". Use keywords to locate examples of changes in particular foods such as butter, water, or popcorn, or use the free text search.
The following Building Science Concepts books, published by Learning Media for the Ministry of Education, are about changes in food:
Book 15 Where's the water? (2001)
Book 16 Sand, salt, and jelly crystals (2001)
Book 23 Fresh food (2002)
Book 24 Preserving food (2002)
Book 53 Moulds are fungi (2004)
Book 56 Bread (2004)
Book 57 Eggs (2004)
Book 58 Ice (2004)
Ministry of Education (1998). Making better sense of the material world. Wellington: Learning Media.
The following Level 2 exemplar is about material change:
What a mix-up!
ARBs