Tea

Tea

Pencil and paper
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
How to do this task: 

  • Fill a beaker with cold tap water. Then place this beaker on a tripod, which is sitting over a burning candle. (See diagram below). Leave for 2 minutes.
  • Carefully drop a small amount of tea down the side of this beaker.
tea-heatsource.png
 
a)
Write down all your observations for the "movement" of the tea leaves in the water.
 
 
 
 
 
 
 
 
 
b)
On the diagram above, use arrows to draw the path that the tea leaves took once they had reached the bottom of the beaker.
 
c) Explain why the tea leaves moved in this way.

 
 
 
 
 
 
 
 
Task administration: 
[Equipment: Candle; 250 mL beaker; tripod; gauze; tea leaves from a used tea bag.]
Level:
5
Curriculum info: 
Science, Investigating in science, Physical World
Keywords: 
physical inquiry, energy, convection, exploring
Description of task: 
For this practical task students investigate convection currents when tea leaves are placed into a beaker of water that is being heated. They are asked to make observations and to provide an explanation of what they have observed.
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 describing being about what you see, and explaining being about what your observations make you think.
Capability: Interpret representations
This resource provides opportunities to discuss the conventions of  arrows in diagrams and how they clarify the meaning for the reader.
 
 
Science capabilities: 
Gather and interpret data, Interpret representations
Answers/responses: 

a)

There are two main observations required.
i)   The tea that was on the beaker bottom above the candle began to move upwards. Some tea was moving upwards.
ii)  Tea at the surface that was not above the candle (or specific area named) was moving downwards. Some tea was moving downwards.

b)

Draws a path, with an arrow showing tea rising above the candle, and an arrow showing downward movement on the other side of the beaker. (See diagram).

c)

Tea moved upwards because of the warmer water rising.
Tea was moving downwards with the cooler water sinking.