Do different materials have a different effect on thermometer? Find the effect of alcohol on an outdoor thermometer.
Things Required:
Outdoor thermometer
Cotton ball
Rubbing alcohol
Directions:
Lil the thermometer on a table undisturbed for three minutes; this will allow it to register the temperature of the room. Blow your breath across the thermometer bulb about 15 times.
This Is What Happens:
The liquid in the thermometer rises.
Directions:
Moisten a cotton ball about the size of a walnut with rubbing alcohol. Spread a thin layer of the wet cotton across the bulb of the thermometer. Blow your breath across the wet cotton about 15 times.
This Is What Happens:
The liquid in the thermometer moved downward.
Science Behind It:
The temperature of one’s breath is about 98.6°F, which is higher than the air temperature in the room. The heat from your breath warmed the liquid in the thermometer and caused it to expand. Expand means that the molecules move farther apart and take up more space, thus the rise of the liquid in the thermometer.
The cooling effect of the alcohol is due to the evaporation of the alcohol around the thermometer bulb. Evaporation occurs when a liquid absorbs enough heat energy to change from a liquid to a gas. The alcohol takes energy away from the liquid in the thermometer bulb when it evaporates, causing the liquid to cool. Liquids contract when cooled. Contract means the molecules get closer together and take up less space; thus the liquid in the thermometer moves down.
