Solar4Scholars: A simple project on solar heating for pools

What you will need

Know how big the bottles are. Whether they are 2 liters or another size, it doesn't matter, as long as they are the same size and filled to the same level.


  1. Fill the bottles with water.
  2. 2. Set them in three different lighting conditions:
    • one bottle stays in the shade inside the house
    • a second bottle is heated by a lamp or other electricity
    • a third is left out in the sun.

    Note: for the third bottle, be sure to monitor sun conditions: for example, whether it is hot and sunny, variably cloudy or overcast.

  3. 3. Measure each of their temperatures. At the beginning, they should be the same.
  4. 4. Monitor temperature change every hour and keep track of which changes the fastest and the most.
  5. 5. Graph your results:
    • A separate line will represent each bottle in each kind of condition.
    • Each hour will be marked off on the bottom of the graph (and)
    • The temperature will be indicated on the left side of your graph.


This experiment will give you a good indication of solar hot water heating conditions in the area in which you live.

Note that the sun's effectiveness may be affected by seasons or even by daily weather changes and also keep in mind that the light bulb or other form of electric energy costs money from the utility company.

Which bottle of water heated faster?

How much was the difference in temperature from the bottle that was kept in the shade?

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