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Physics of observations around us.

Please help with a brief explanation for each of the following questions

1. If you fill a glass bottle with water and seal it tight and leave it in a hot car on a summer day, it will break (I can testify to this from personal experience!). Likewise, if you fill a glass bottle with water and seal it tight and put it in your freezer, it will break. (This is also why frozen water pipes can break in the winter in cold climates.) What physical principle(s) is/are at work here? Is it the same principle or different ones? Explain.

2. In a room, heaters are best placed on the floor or close to the floor, while in a refrigerator the cooling coils are usually located on the top part of the refrigerator, with the freezer. Is this simply a matter of convenience? It might be -- that way, heaters are kept out of the way, and freezers are located at eye level and within easy reach. Is there a physical principle involved? If so, name it and explain how it applies to room heating and refrigerators.

3. Some common problems that all homeowners face at one time or another include buckling sidewalks due to changes in temperature from summer to winter and cracking caulk in bathtubs due to daily changes in temperature (from running hot water and heating the tub up, then letting it cool down to often 55 to 60 degrees F.). Explain what physical principle(s) is/are at work and how it(they) apply to these situations. Can you name any other examples from everyday life?

Solution Preview

1. Water has its maximum density at 4°C. If you change the temperature, density decreases regardless of the change (increase/decrease). Decrease in density will result in increase in volume which can break bottles if they are sealed tight.

When water freezes at 0°C, at atmospheric pressure, its volume increases by about 9%. This is the reason why bottles break inside a freezer. When the volume increases, there is no ...

Solution Summary

All questions answered with enough explanations. A good reference and guide.