Dynamic Planet B/C

[EastStroudsburg13]

Well, I guess they can do that if they make C significantly harder than B. Then, with the difference they could keep the "no resources allowed" a constant. Plus, I guess all teams have to deal with the same rules.

[rocketman1555]

its easy to make C harder just by making the test more in depth

for note sheets i think one is necessary so you have P/S wave travel times, which would be a pain to memorize, and so you can have the scales in front of you, other than that they are pretty useless

[Glacierguy1]

I think that it should be made a rule to provide the S/P wave travel time at every competition and allow teams to bring in their own compass to the competition, so the team that is providing the compasses doesn't have an unfair advantage.

[rocketman1555]

They don't allow teams to bring compasses? I took one to competitions and nobody said anything to me.

[scienceolympiadist]

They usually provide the compasses, and they should be the same for all teams. Although personally, I dislike doing actual trangulation...

[fmtiger124]

I would prefer to bring my own compass--it's easier and sometimes with compasses you have to get used to using a new one. But my mind is blanking on what we did during competition.

[doctor]

for a invitational the the event organizer forgot compasses so we had to improvise
and at states they gave us a compass but didn't really give us any info to find the epicenter
like if you know p travel time and s travel time and s-p interval how would you graph that onto the travel time scale if you dont know the distance b/c the distance is what ur trying to find?

[fmtiger124]

for a invitational the the event organizer forgot compasses so we had to improvise
and at states they gave us a compass but didn't really give us any info to find the epicenter
like if you know p travel time and s travel time and s-p interval how would you graph that onto the travel time scale if you dont know the distance b/c the distance is what ur trying to find?

aren't they not supposed to tell you how?
It was on our sheet but I also remebered from E. Science the previous year.
anyway If you know the amount of time between the s-p waves you go to the y -axis and find that amount (mark it on a sheet of paper).
You then put the distance that you found in between the S and P wave lines--wherever it fits, you look down to the X-axis and see what the reading is--thats the distance to the epicenter.

EDIT: I'm going to see if I can make a diagram
EDIT2: I lied the diagram failed

[andrewwski]

I haven't taken Earth Science since 9th grade, but I'm pretty sure if you know the time of the P and S-waves, you can use a chart to find the distance. Obviously they're NOT going to tell you the distance if that's what they want you to find.

Then if you know the P and S-wave travel times from 3 different seismographic stations, you can use the distances you found to pinpoint the epicenter on a map.

Example:

Here's a P/S wave travel time chart.



Let's say they tell you the P-wave arrived at Seismograph Station A at 10:21:00, and the S-wave arrived at 10:24:20. You use this information to find that the time of arrival between the P and S-waves is 00:03:20, or 3 minutes and 20 seconds, or 3 and one-third minutes. Now, look on your table to see where the vertical distance between the P and S curves is 3 minutes and 20 seconds. You find this occurs at the x-value, or epicenter distance, of 2 x 10^3 km, or 2000 km.

[doctor]

oh
thats how you do it...
thanks thats really helpful since next year's topic is the same as last year