You will need to pour hot water into the metal tube. This should only be done with gloves on to avoid burning your hands.
The length of the tube is $L=50.0~\textrm{cm}$, the outer diameter of the tube is $D=12~\textrm{mm}$, the density of water is $\rho=1.00~\textrm{g}/\textrm{cm}^3$, and the specific heat capacity of water is $c=4.2~\textrm{J}/(\textrm{g}\cdot^\circ\textrm{C})$. The metal part of the tube conducts heat very well. One half of it is wrapped with black electrical tape of thickness $d_b=0.68~\textrm{mm}$, and the other half is wrapped with white painter's tape of thickness $d_w=0.38~\textrm{mm}$.
Attention! You must not wet the painter's tape. You mustn't remove rubber cork from the thermometer!
We will study the cooling of water in a tube with non-uniform thermal insulation. The cooling dynamics is governed by two phenomena:
To denote quantities related to the painter's tape, we will use the subscript «$w$», and to denote quantities related to the electrical tape, we will use the subscript «$b$».
B1 2.00 Measure the dependence of the temperature inside the tube $T_\text{in}$ and on the surface of electrical tape $T_b$ on time $t$. Record at least 10 data points.
The measurements begin by pouring $20~\textrm{ml}$ of hot water into the tube. When you do this, the first portions poured in will eventually cool down, as heat is lost to warming up the entire system. Before taking measurements, vigorously mix the water inside the tube to achieve a uniform temperature, ensure that the tube is sealed with corks on both ends!
To secure the thermometer without a casing on the surface of the electrical tape, fasten it with a rubber band. During cooling, the tube should be placed on clips to minimize heat exchange with the table.