LAB 24
NOT SURE WHiCH 0NE iS LAB 24~BUH` WHATVER...
problem:how does variations in particle size affect rate at which particles settle through quiet water?
materials:plastic column, water, 3 different particles(rocks pebbles, and sand)
procedures:
1)fill a plastic column 3/4 of the way with h20.
2) drop a pinch of particles that vary in size into plastic column separately.
3)record the time it takes for particles to settle in water.
[PART B]
1) repeat steps one from part A
2) drop 20 to 50 mililiters of the same varied particles that are mixed together into plastic column.
3)record time for each to settle and draw how they`ve settled in.
conclusion:
--1 what effect does grain size have on the rate at which particles settle? (remember you determined time)
--2 when materials made up of particles having varied sizes and densities are dropped into quiet water, in what pattern do they generally settle out?
--3 what is the distribution of particle sizes in layers of sediment that have been deposited in quiet water?
--4 sediment is deposited into a lake from a tributary stream. describe probable distribution of grain sizes from the mouth of the stream all the way out into the lake..explain!
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LAB 23
problem :how can you determine the absolute age of rock layers?
materials: a plastic cup & 100 pennies
procedures:
1-place all pennies in the plastic cup
2-shake pennies & randomly drop some out of the cup
3-record your results in data chart
4-repeat steps 2-3 until you have 100% decayed objects. (should be about 8 trials)
conclusion:
1- what kind of objects would not be useable in this investigation?why? explain
2-what effect if any does the way in which you shake the plastic cup have upon the number of objects that decay?
3-what effect, if any, does the number of shake per trial have on the number of objects that decay?
4-according to the graph, what is the half line(number of trials for the objects to decay) for this model?
5-convert graphaxis for trial number to a time scale by letting 1 trial equal to 1,ooo years. what is the half line for the substance in years?
6- what happens to the percent decaying with succeding trials?why?
7-would changing the amount of not decayed materials originally present affect rate of decay? would it affect half-line? explain.
8-in what ways is the model of decay in this investigation similiar to radioactive decay in nature? in what ways is it different?
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