Keeping a bucket of water in a room can potentially increase the room's humidity, but it does not directly increase the room temperature. However, changes in humidity can indirectly affect our perception of temperature.
When water evaporates, it absorbs energy from its surroundings, which can lead to a cooling effect. This is why we feel cool when we sweat on a hot day—evaporation of sweat takes heat away from our bodies. Similarly, if the air in the room is relatively dry, the water in the bucket can evaporate, causing a cooling effect in the immediate vicinity of the bucket.
On the other hand, if the air in the room is already humid, evaporation from the bucket may be minimal, and the cooling effect would be negligible. In this case, the bucket of water would primarily contribute to increasing the room's humidity rather than affecting the temperature.
It's important to note that the overall impact of a bucket of water on the room's temperature and humidity will depend on several factors, including the size of the room, the initial temperature and humidity levels, and the rate of evaporation. Additionally, any cooling effect resulting from evaporation would be localized near the bucket and may not significantly affect the entire room.
If you're looking to cool down a room, more effective methods include using fans, air conditioning, or opening windows to allow for natural ventilation. These methods directly affect the air temperature and can have a broader impact on the overall comfort level in the room.