The Tea Scale
The tea scale is a way to look at the dangers, or lack of with non-ionising treatments. It puts into perspective the kinds of energy these machines are imparting using something more everyday, like tea. Click on the video to learn about the tea scale used for the non-ionising radiation parts of the website.
​
The tea scale below shows the amount of energy or heat you would receive from specific procedures in terms of how many cups of tea you could heat up to boiling with that energy.
How does it work?
This cup shows the range of energies you could receive from the procedures discussed in this website. Blue is the heat received from an average MRI scan, and near the top, pink and orange are the average amounts you can receive from Microwave and Radio frequency ablation respectively.
The energy required to heat a cup of tea can be calculated in the following way:
​
​
​
-
Q is the energy required to change the temperature of a material
-
m is the mass of the material you are dealing with, in our case tea. We will use C = 4.184 kJ/kgK
-
ΔT is the temperature change in either Celsius or Kelvin. For tea we assume an 80°C temperature change. This is because we are starting at room temperature, 20°C, and ending at the boiling point of water, 100°C
​
Putting these values into the equation gives us an energy of Q = 84kJ
