Cat food and soup

Cat food and soup

Pencil and paper
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Working with Students
What do you think?

In your group:

  1. Discuss each of the three ideas in the concept cartoon.
  2. Decide which idea (or ideas) you think is/are correct.
  3. When you have finished the discussion, fill in the chart below.  
a)
   Statement We agree /disagree Our reasons
i)
Li said "I think they will both go the same distance because they are rolling on the same surface."
  
  
ii)
Debra said "I think the can of cat food won't roll as far because it is too heavy."
  
  
iii)
Pania said "I think the can of soup won't go as far because the soup will be rubbing inside the can."
  
  
   
b)
We predict the can of ______________________________ will roll further because ...
 
 
 
 
Task administration: 

[Equipment: For each group: 1 copy of the concept cartoon, 1 can of cat food, and 1 can of soup of the same size (there will be a slight variation in weight)]

  • The concepts involved in this activity are complex, so students should have had many experiences in exploring rolling and friction before they are asked to complete it.
  • The activity is best undertaken in a small group of about three students so they interact with the ideas presented. Present them with the concept cartoon first, then, after they have discussed it, ask them to complete the answer sheet. This can be followed by a whole class discussion.
  • The assessment should always be followed by students planning and carrying out an investigation to test their predictions. A class discussion about each groups' results and the reasons given for these, will give the teacher additional information about the students' understandings of friction.

 

Level:
3
Curriculum info: 
Science, Investigating in science, Physical World
Keywords: 
physics concepts, forces, friction, predictions, group assessment, concept cartoons
Description of task: 
Task: students, in small groups, discuss a concept cartoon about rolling cans, before making a prediction about which will roll further. Assessment focus: making predictions about friction.
Curriculum Links: 
Science capabilities
The capabilities focus is brought about by the conversations you have and the questions you ask.
 
Capability: Gather and interpret data
This resource provides opportunities to discuss 
  • that predicting is not guessing, but applying science understandings to a specific context.
  • describing being about what you see, and explaining being about what your observations make you think.
 
 
Answers/responses: 
     

Statement

Example of student reason for choosing this statement

Concept links and suggestions for follow up activities

a)

i)

Li
"I think they will both go the same distance because they are rolling on the same surface."

 No student in the trial chose this option. If students choose this answer, they may be only considering external friction (rubbing between the outside of the can and the surface). Next step: investigate what is happening inside the cans.

  • Shake water inside a dirty jar to demonstrate the rubbing action of water.
  • Roll identical jars, one full of water, the other full of cotton wool. Observe what is happening inside the jars. Set up fair tests to see which rolls further.

 

  

ii)

Debra
"I think the can of cat food won't roll as far because it is too heavy."

 "See the weight? We think the lighter one will go (further)".

If students choose this answer, they may be considering weight as the most important variable.
Next learning step: investigate rolling light and heavy objects of the same size, for example, large marble, ping pong ball, golf ball.

  

iii)

Pania
"I think the can of soup won't go as far because the soup will be rubbing inside the can."

 Because of the stuff inside rubbing (referring to a previous activity).

If students choose this answer, they may be considering internal friction.
Next learning step: carry out own investigations on how contents affect rolling.

b)

  

Cat food
Less friction occurs inside the can because the contents do not move around.

 

Teaching and learning: 
  •  
Diagnostic and formative information: 
  • This task was trialled with a class of younger students (Years 1 to 3) who had been exposed to the idea of internal friction, and a group of Year 6 students who had not. The younger students were not asked to record their answers.
  • Students in both groups were most likely to consider that weight was the factor that most influenced how far the cans rolled.
  • Check that the reason given matches the statement. One group chose iii) but gave as their reason: "because the soup is heavier and it's harder to roll". Further questioning to unpack the students' reasoning is required.
  • Some of the older students thought that the soup would go further: "the soup would go further because the soup inside will keep rolling". The cotton wool/water activity could be a good follow up investigation.
  • The Year 6 boys in particular enjoyed debating the concept cartoon. More information about their ideas was gained from listening to them talking about the different options than reading their written responses.
Next steps: 
Refer to Marking student responses