Because it will bust.
That depends on how hot the water is in the cup. Use the thermometer to measure it and see.
When a thermometer bulb containing mercury is placed in hot water, the mercury inside expands, causing the level of mercury to rise. This expansion of mercury is used to measure the increase in temperature accurately.
A thermometer is used to measure the temperature of hot water.
When a thermometer is quickly dipped in hot water, it won't do anything. If you leave the thermometer in the hot water, the temperature shown will read higher. The temperature shown will not exceed the temperature of the water.
The bulb of a clinical thermometer breaks when placed in very hot water because the sudden increase in temperature causes the air inside the bulb to expand rapidly. This rapid expansion of air creates pressure within the bulb, leading to its breakage.
The mercury level in a thermometer placed in a hot tub of water will rise as the temperature of the water increases. This is because the volume of liquid mercury expands with higher temperatures, causing it to climb up the measuring scale in the thermometer.
If you ever want to measure a temperature above 212 degrees, you're better off hanging the thermometer into the air in the oven. Since it's a hot-air oven, you want to measure the air. If it were a hot-water oven, you might prefer to measure water. But even then, what are you gonna do above 212, when the water goes away and all you have in there is steam ??
When a thermometer is placed into something cold, the liquid inside contracts and decreases in volume. This causes the liquid level to decrease, indicating a lower temperature on the scale of the thermometer.
a thermometer
When a thermometer is placed in hot water, the heat causes the liquid inside (mercury in this case) to expand. This expansion initially pushes the mercury down slightly due to increased pressure. However, as the mercury absorbs more heat, it expands further and eventually rises to reflect the higher temperature of the hot water.
Because the hot water heat transfers into the rod.
The liquid in thermometers expands when temperature increases (and contracts when temperature decreases). When it expands, the only place for it to expand 'to' is up the thermometer (into the empty space above it).