24 days of kitchen oceanography
Each day a new experiement will be posted here. Reveal what is hidden behind the windows by clicking on the arrows below.
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Thermal expansion
Why is the water level in the straws not the same?
Experiment 24:
We use a small bottle which we fill completely with cold, dyed water. Then we take a clear straw, put it into the bottle, and seal the mouth of the bottle with some playdough. Pressing the playdough down into the bottle will make water rise up into the straw.
We then place the bottle into a water bath with ice cubes and observe the water level in the straw sinking. If we now place the bottle into a water bath with hot water, after a little while we can observe the water level rising. Water expands at higher temperatures! We have now built a thermometer. We also showed how the sea level is influenced by changing temperatures.