WorksheetsEarth Science, Friday Bell Ringer, 12.15.17
Total questions: 10
Worksheet time: 22mins
Name
Class
Date
1.
When an unstable radioactive atom decays, it usually turns into:
a)
a more stable atom
b)
a less stable atom
c)
the exact same atom but with less pure energy
d)
empty space
2.
Radiometric dating is possible because the rates of decay of radioactive isotopes _____.
a)
change over time
b)
change from place to place
c)
are constant
d)
vary widely
3.
The time it takes for 50% of the nuclei in a radioactive sample to decay to its stable isotope is called _____.
a)
the daughter product
b)
geologic time
c)
the half-life
d)
the half-time
4.
You find a rock sample with radioactive atoms present. If 25% of the original radioactive atoms were present, how many half-lives has the rock been around for? (Hint, at Half-Life = 0, you start with 100%)
a)
zero
b)
1
c)
2
d)
3
5.
If the half-life of a radioactive group of atoms is 100 years, then how old is the rock if there have been two half-lives?
a)
25 years
b)
200 years
c)
400 years
d)
800 years
6.
What percent of carbon-14 would be left after 5730 years?
a)
100%
b)
75%
c)
50%
d)
25%
7.
According to the law of superposition, the oldest fossils are found
a)
At the top of the rock layers
b)
Near the bottom of the rock layers
c)
In the middle of the rock layers
d)
Somewhat near the surface
8.
The ________ states that layers of sediment were originally deposited horizontally under the action of gravity.
a)
law of superposition
b)
law of horizontality
c)
uniformitarianism
d)
unconformities
9.
What 2 things make a good index fossil?
a)
Good looks and a great smile
b)
widespread and on Earth of a short time
c)
widespread and on Earth for a long time
d)
only found in Clinton Twp and in every rock layer
10.
Which best describes radiometric dating?
a)
using instruments that detect radioactivity to figure out how old something is
b)
measuring the relative amounts of a radioactive isotope and a daughter product to figure out the age of a sample
c)
measuring how quickly the different radioactive isotopes in a sample decay to figure out the age of the sample
d)
using short-wavelength electromagnetic radiation to determine the age of a sample
100 %
