The mineral content of clay also affects the temperature level at which it hardens.

VOA: special.2009.09.09

When the temperature gets above the level you want it to be.

就在当温度超过你想要的温度时

耶鲁公开课 - 生物医学工程探索课程节选

If the temperature drops below a certain level it sends a signal, 'turn on the heat', and that signal stays on until it gets a negative signal to turn off.

如果温度降到一定程度以下时,探测器会发送一个信号,打开加热器,直到加热器再收到关闭的信号,它就会一直开着

耶鲁公开课 - 生物医学工程探索课程节选