Fermi Questions C

[sr243]

Okay, so my partner and I are doing this for the first time next week. Could someone explain how it works to me and suggest what I should do to prepare? I've read stuff on the sites and it just sounds so complex. It have to be easier than my brain is making it...

I can give you some tips to study. You have to believe that you can study for this event or else you wouldn't try to study because it takes time. I could have done better if I had more time to memorize the facts and I asked my partner to do so, but he kinda focused on rocks instead (sorta worth it because we got 4th by 1 point more than 6th). Anyways you need to look up some facts and conversion. I used the base unit of meter and grams. So find important facts like radius of Earth, surface area of Earth, and weight of Earth in scientific notion. Memorize these facts. Then apply them as much as possible to the questions. I will list off some other important ones but you can find more and study more. This helped us improve. I will start off with a few here but you need to study more if you want to do well. Try to remember one significant digit in addition to the number of tens.
Time (seconds to days/years)
Oceans/Lakes size (cubic feet)
Light year (Meters)
Distance to planets(Meters)
Number of sand to make a gram
Population
Units (angstrom, nanometer, metric ton)
Mole (6.02x10^23)

[astroblue]

Does anyone know or have a list of constants to memorize?

[claribassist13]

Unfortunately, there is not great way to prepare for Fermi Questions. You can take practice tests and look up random facts on websites, but there's no way to ensure that you'll know all the material on the test. However, during the test, I would recommend actually thinking about the questions when you form a guess. A lot of people just think, "I don't know the answer, so I'll just guess 3" and then the answer is 10. Break the problem into parts when possible and just keep multiplying the smaller, more manageable parts until you find the answer. If you don't know the answer, just form an educated guess. For example, if the question is, "How many molecules are in a cell?," don't think in the hundreds. Think of all the components of a cell: ribosomes, vacuoles, DNA, and so many other things! You might not be able to determine the answer, but you should at least be able to narrow the range of possibilities to somewhere in the 9-15 range. This is a much better estimate and this sort of very rough, but not uneducated, guessing, will help improve your score immensely.

Thanks for the tips! We are the only group in my school doing it, so we are all on our own... It should be fun though!

[claribassist13]

Okay, so my partner and I are doing this for the first time next week. Could someone explain how it works to me and suggest what I should do to prepare? I've read stuff on the sites and it just sounds so complex. It have to be easier than my brain is making it...

I can give you some tips to study. You have to believe that you can study for this event or else you wouldn't try to study because it takes time. I could have done better if I had more time to memorize the facts and I asked my partner to do so, but he kinda focused on rocks instead (sorta worth it because we got 4th by 1 point more than 6th). Anyways you need to look up some facts and conversion. I used the base unit of meter and grams. So find important facts like radius of Earth, surface area of Earth, and weight of Earth in scientific notion. Memorize these facts. Then apply them as much as possible to the questions. I will list off some other important ones but you can find more and study more. This helped us improve. I will start off with a few here but you need to study more if you want to do well. Try to remember one significant digit in addition to the number of tens.
Time (seconds to days/years)
Oceans/Lakes size (cubic feet)
Light year (Meters)
Distance to planets(Meters)
Number of sand to make a gram
Population
Units (angstrom, nanometer, metric ton)
Mole (6.02x10^23)

That is super helpful! Thanks a ton!

[Schrodingerscat]

The Kansas state test had two interesting E&M physics problems. They were calculating the value of the magnetic field in T and the electric field in V/m where a person were sitting next to a 60W lamp. Anyone know how I could have estimated this?

[astroblue]

Another interesting problem from our regional's test, it's actually not too hard:
If you put 1 cent in a savings account, and it doubles every week, how many pennies will you have at the end of a year?

[Schrodingerscat]

Another interesting problem from our regional's test, it's actually not too hard:
If you put 1 cent in a savings account, and it doubles every week, how many pennies will you have at the end of a year?

That one is some exponential math with a little to memorize. 2^52=10^x, log(2^52)=log(10^x), 52log(2)=xlog(10), 52log(2)=x. If you just remember that log(2) is about 0.3, you can find that x is 15.6, thus your power is 16. However, this is also where the flaw of rounding up at 5 and not sqrt(10) appears, as 10^15.6 is 4*10^15 and would be Fermi answer 15.

[2win]

4 days before competition, I've been thrown in. So... besides lots of constants to be memorized, what else should be on my list of things to do?

[Phenylethylamine]

4 days before competition, I've been thrown in. So... besides lots of constants to be memorized, what else should be on my list of things to do?

Get used to the idea of what is reasonable.

For example: if your final answer is supposed to be the mass of the moon in kg, and you're getting 2 or 3, is it really reasonable that the moon's mass would be the same order of magnitude as that of a human or a car? If you're trying to calculate the number of cells and the number of atoms in the human body, and you're getting that the answer for atoms is only one more than the answer for cells, is it really reasonable that each cell in the human body only contains ten atoms?

Don't just put down numbers blindly because your calculation turned them out; try to think, "Okay, what else would that be the size of, and is it reasonable that these two things could be about the same size?"

[nejanimb]

If anyone wants a practice test, I wrote the test for the Virginia State tournament, and I've gotten permission to release it.

http://cl.ly/3X2w3b3W0v042q0T3v2r

Let me know what y'all think. Hope it helps in your preparation.