How to Make a Thermometer

https://www.wikihow.it/Costruire-un-Termometro

07-08-2024 |
italia |
Acqua |
fai da te |
Termometro |
Contenitore graduato |
Bottiglia di plastica da 500 ml |
Alcol disinfettante |
Cannuccia |
Argilla |
Pennarello indelebile |
Colorante alimentare rosso (facoltativo) |

Traditional thermometers measure temperature using mercury, but you can make a homemade one with just water and disinfectant alcohol.While thermometers like this can't be used to check if you have a fever, they can still measure the temperature of your home.With some simple common materials, you can make a fun science experiment that can help you measure temperature!

Part 1

Part 1 of 2:

Building the Thermometer

Download PDF

1
Mix 75 ml of cold water with 75 ml of disinfectant alcohol. Use a measuring cup to mix these two liquids in equal parts.You can mix the solution in the measuring cup or pour it directly into a 500ml plastic water bottle.^{[1]
X
Research source}
- You can buy disinfectant alcohol at the pharmacy.
- Avoid drinking the mixture once you have made it, as it is not drinkable.
2
To make the solution more visible, you can add a few drops of red food coloring. The dye makes the water more similar to the mercury used in traditional thermometers.Pour 1 or 2 drops into the solution and mix it by stirring.^{[2]
X
Research source}
- This step is optional if you don't have food coloring on hand.
3
Place a straw in the bottle so it doesn't touch the bottom. Use a clear, straight straw so you can see the liquid inside.Insert it into the bottle, fixing it so that it is immersed, but it is important that it reaches just above the bottom.^{[3]
X
Research source}
- If the straw touched the bottom, the water and alcohol solution would not be able to enter it and the thermometer would not work.
4
Seal the bottle by closing the top with clay. Mold the clay over the opening of the bottle, so that no air can pass through.Make sure not to squeeze or cover the hole in the straw, otherwise the thermometer will not work.Once all the clay has been added, the thermometer will be ready for use.^{[4]
X
Research source}
- You can buy clay at DIY and art stores.
- Alternatively, you can drill a hole in the bottle cap with a diameter just large enough to let the straw pass through, then screw it on.Seal all openings with small amounts of clay.
Advertising

Part 2

Part 2 of 2:

Finding Temperatures

Download PDF

Look for the level of solution inside the straw and draw a line on the bottle with a permanent marker.Measure the room temperature with a mercury thermometer to find out the actual temperature.Write it down next to the line on the bottle.^{[5]
X
Research source}
2
Place the bottle in a container of hot water and trace the height of the liquid level. Fill the bottom of a container large enough to hold the thermometer with hot water.Place the thermometer in the water and watch the liquid level inside the straw rise.When the level stops, draw a line on the bottle with a marker and mark the actual temperature of the water.^{[6]
X
Research source}
- The heat causes the air inside the bottle to expand.Since the bottle is hermetically sealed and can only expand through the straw, the water level rises due to this expansion.
- The solution can leak out the top of the straw if the water temperature is too high.
3
Test the thermometer in cold water and mark the temperature on the bottle. Place the bottle in another container with cold tap water.Notice how the level of the solution in the straw progressively drops.When it stabilizes, mark the actual temperature on the bottle.^{[7]
X
Research source}
- The air contracts as it cools, causing the level of the solution inside the straw to drop.
- The mixture inside the thermometer will freeze below freezing and will not work.
Advertising