A student wishes to check the upper and the lower fixed points on a Celsius scale thermometer.
She has four beakers P, Q, R and S.
Beaker P contains a mixture of ice and salt.
Beaker Q contains a mixture of ice and water.
Beaker R contains boiling salt solution.
Beaker S contains boiling water.
Which two beakers should she use to check the fixed points?
Wähle eine der folgenden: