Make Your Own Thermometer

In 1593, the Italian astronomer Galileo invented the first thermometer, called the sensor, but it was not highly accurate. It was developed in 1641—alcohol was used as an indicator. In 1714, Daniel Gabriel Fahrenheit invented the mercury thermometer which is still used today. The concept of thermometers is based on the scientific principle which denotes that the changeable physical properties of some substances—such as the volume of liquid and resistance—change with temperature.

Type of Activity: Physics

Materials Needed: 

1. One plastic bottle
2. Cold water
3. Natural color
4. Hot water
5. Two straws (one straw)
6. One deep glass bowl
7. Clay
8. Cardboard (12 x 5 cm)
9. One coloring pen
10. One ruler.

Target Group: 12 years old

Duration: 45 minutes

Steps of the Experiment:

1. Fill the bottle with water, then add drops of the natural color.
2. Put a piece of clay around the top of the straw.
3. Insert the straw in the bottle while pressing on the clay to block the bottle opening. Make sure that the surface of the water in the straw is higher than that in the bottle.
4. Put the bottle in one bowl filled with cold water, then place it in the other plate filled with hot water.
5. Fix the upper part of the straw to a piece of cardboard by making two cuts in it.
6. Use the ruler and the coloring pen to add scale markings on the cardboard.
7. Observe and register the readings of the scale with each placement.

The water in the straw rises when it is placed in hot water, and declines when placed in cold water.

As the temperature changes, the volume of liquid changes.



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