Question
Our teacher gave us a paper with things he picked and we are suppose to pick one. I picked this one.
1. Which heats faster in a microwae, water, ethanol, or isopropanol? Must compare their heat capacities as well.
I have never done a science fair project and I have no idea how to make this into one. I have tried looking up stuff on the internet on heat capacity of the three above things. Any suggestions on how to go about this?
Answer
If you have a microwave and a thermometer or access to them, this sounds like a science fair project that is pretty readily done by experiment. Water and isopropanol (also known as rubbing alcohol) are easy for a high school student to get, and perhaps your teacher can supply you with some ethanol not suitable for drinking. With the materials in hand, it would be relatively easy to measure their temperatures after subjecting them to microwave pulses. You could subject samples to different length microwave pulses, and see if that affected the relative heating rates. (For example, what happens after a 10-second dose, a 30-second dose, or a one-minute dose?) You could make the samples the same size on the basis of mass (say 200 g) or volume (say 200 mL) or moles.<BR><BR>As for heat capacities, which are sometimes called specific heat, they ought to be easy to find if you ask an actual librarian (as opposed to a virtual one). Heat capacities of many substances are compiled in print handbooks such as the <EM>CRC Handbook of Chemistry and Physics</EM> and even in tables in the back of many chemistry textbooks. There are sources of heat capacity data on the internet, but it is probably easier to use a handbook. (Typing "heat capacity" or "specific heat" into a search engine will turn up definitions rather than tables. You may want to have a look at the NIST Chemistry Web Book athttp://webbook.nist.gov/chemistry/. This is an on-line compilation of lots of thermodynamic data by the US National Institute of Standards and Technology; however, I don't think it is very user-friendly if you don't already know quite a bit about thermodynamics.)<BR>Good luck!<BR>
http://webbook.nist.gov/chemistry/
http://vrd.askvrd.org/services/answerschema.xml
