Microwave Ovens

Microwave Ovens

Pencil and paper
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Further Resources
This task is about planning and doing an investigation, and collecting and interpreting results.
How to do this task

Hot spots are areas of the microwave oven that heat up more than other areas.
  • Your question to investigate is whether microwave ovens have hot spots
  • Your task is to write a plan to test whether your microwave oven has hot spots. After your teacher has seen your plan, you can carry out your investigation.
  • Equipment that you can use: microwave oven; cups; thermometers; water.
Some things to think about before writing your plan:

  • How many cups will I use?
  • Where will I put the cups inside the microwave oven?
  • How much water will I put in each cup?
  • What will the temperature of the water in the cups be at the start?
  • How long will I leave the cups in the microwave oven for?
  • What power level of the microwave oven will I use?
 
a)
 
My plan (Method):  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Plan checked by the teacher:
 
 
Results
b) Now carry out your plan and record your results in the box below.
 
 
 
 
 
 
 
 
 
 
 
 
 

c)
Write a sentence about what your results tell you about the microwave oven.

 
 
 
 
 
 
 
d) What changes would you make to your plan if you were to carry it out again?

 
 
 
 
 
 
 
e) If you were buying a microwave oven, what quality would you look for if you wanted to cook or heat food evenly?

 
 
 
 
Task administration: 
Equipment:
Microwave oven; cups suitable for use in a microwave oven; water; thermometer(s).
  • This task requires students to determine if a microwave oven heats evenly by investigating whether there are any hot spots inside the microwave oven.
  • Students may need to have explained to them what power level means, i.e., low, medium, or high.
  • Microwave ovens range in size so that the number of cups it may hold will vary. Students may need to be directed to consider this as part of their plan (or when they evaluate their plan).
Level:
4
Curriculum info: 
Science, Investigating in science, Physical World
Keywords: 
energy, microwave ovens, fair testing
Description of task: 
For this practical task students write a plan to find out if a microwave has a 'hot spot'. Students carry out their plan, collect, and interpret results.
Curriculum Links: 
Science capabilities
The capabilities focus is brought about by the conversations you have and the questions you ask.
 
Capability: Gather and gather data
This resource provides opportunities to discuss the methods used in investigations and how the variables make it a fair test e.g., how they will make the data reliable. 
Science capabilities: 
Gather and interpret data
Answers/responses: 
 
 a) Method:

  • Describes at least three different places in the microwave to be tested, e.g., side, middle, and centre.
  • States that each cup will have the same amount of water.
  • States that each cup will have the same initial water temperature.
  • Gives a power level and time for heating.
  • Mentions water temperatures to be recorded before and after.
b)

Results:

  • Has accurately recorded results, i.e., temperatures before and after or temperature increase recorded for each cup used.
  • Some aspect of results is missing or incomplete, e.g., only states final temperature of water.
  • Results have been drawn up in a table.
c) Writes a statement consistent with their results.
d) Student identifies areas of their plan that need re-thinking after they tried it out, e.g., may want to include repeat trials and take an average, try other areas in the microwave, change the power level they used, etc.
e) A microwave that does not have hot spots so that food is cooked/heated evenly no matter where it is put in the microwave.