Having a Printable Thermometer at your disposal is a good idea when teaching both the concept of temperature measurement, and the equivalencies between Degrees Celsius and Degrees Fahrenheit. Temperature is only one of the five main areas of measurement your child needs to know in elementary math.
I have one Pdf File containing one large Thermometer, showing both Degrees Celsius and Degrees Fahrenheit measurements.
Click on the image to open the Pdf, to print now.
You can use this printable thermometer as a thermometer chart, when originally teaching the concept of temperature. As your student progresses, it can be used for conversion between Degrees Celsius and Fahrenheit.
When you print off this printable, if you want to use it as a manipulative for your kid, consider printing on strong white card, and cut out the thermometer. Then slip a paper clip over the scale, with the majority of the paper clip behind the thermometer, leaving just one line across the front of the scale.
Then, your child can slide the paper clip up and the scale, to get conversion figures between Degrees Celsius and Fahrenheit.
The best thermometer manipulative is in fact a real thermometer. You most likely have one at home anyway. Fill some containers with different temperatures of water. Have your child measure these amounts and record them. You can turn this into a very basic Data Analysis project for younger kids.
Hopefully you can get exactly what you need here. If there is something very particular you are looking for, please don't hesitate to contact me. I will do what I can to get you it.
And don't forget to check out all the other great printable manipulatives I have available for you here.