Why thermocouple response time is faster than RTD?

Thermocouple sensing only the hot end of a "point", the heat capacity is relatively small;

Resistance thermistor must be attached to the skeleton molding, plus the skeleton after the heat capacity of the relatively large.

The above is only on the traditional industrial assembly thermocouple, RTD.

Now with vacuum coating process production of RTD head only Φ1 × 2mm size, heat capacity has been very small;

And sealed armored thermocouple to the hot end of the complete package but may make the heat capacity increased;

Industrial Φ6mm armored thermocouple, RTD core, the response time is almost no difference.