Update your table of
Half Life Lab
1. Place 100 atoms (pennies) into the plastic box all with
the heads up.
2. Shake for 10 seconds
3. Spill pennies on tray and remove the decayed atoms
(represented by tails)
4. Count the number of un-decayed atoms (represented by
the appearance of heads) left on the tray
5. Enter the number of decayed and un-decayed atoms into
6. Put the un-decayed pennies back in the box.
7. Repeat steps 2-5 until all the atoms have decayed
8. Create a line graph to represent your data in Table (# of
un-decayed atoms vs. time)
Lab Analysis Questions
1.What does it mean when we say an atom
2. At the end of each half-life, at
approximately what percentage are the
3. Does the amount of time you shake the
box affect the outcome?
4. Do the number of atoms you start with
affect the outcome? Explain
5. How do scientist use radioactive decay to
date fossils and artifacts? 3
1.You are a historian and discover a long lost scroll.
You run some tests on this scroll and discover that 85%
of the carbon 14 that was originally present has
decayed. Use your graph to estimate how many years
have passed since the scroll was created.
2. Why would it be difficult to date an item that was
1,000,000 years old using this technique?
3. Why would it be difficult to date an item that was only
12 years old using carbon dating?
4. What are 2 ways that this model is an inaccurate way
to describe the decay of radioactive atoms? 4
• An entire species
• NATURAL PART OF
• Estimated that 99.9% of all
species to have ever lived
have become extinct
• Average survival is 2 to 10
Extinction Type How it happens….
Natural Extinction Climate change, rainfall, volcanic
eruption, earthquake, change in
geology, predators/ disease
Mass Extinction Large numbers die out in a short
amount of time (50%) Evidence
includes abundance of fossils in
Asteroid Theory Catastrophic impact with asteroid;
thick clouds blocked out sunlight
Gradual Theory Movement of tectonic plates
causes global climate change due
to volcanic activity blocking out
Us and The “E” Word
• Extinction rate has drastically
• Many believe this is due to human
• We have been directly linked to
habitat destruction, invasion,
pollution, forest burning, overgrazing,
overharvesting, climate change,
What sorts of species are most
vulnerable to extinction?
Review… try not to look!
1. What is it called when an
entire species dies out?
2. What can be dug up from
Antarctica that allows
scientists to examine layers
to give insight into Earth’s
climate through time?
3. What Law do undisturbed
rock layers follow?
Thumbs up T / Thumbs Down F
True or False
4. Radioactive elements are used to
give an Absolute Age of a fossil.
5. Relative age is an exact numerical
age for a fossil.
6. Epochs are the largest amounts of
time on a Geological Time Scale.
7. The Earth is 4.7 Billion years old.
8. Fossils are often found in igneous
What do scientist believe
caused the extinction of
dinosaurs 65 Million years
GLOBAL CLIMATE CHANGE
What is the underlying cause
of all natural species
What percentage of species
that have ever lived on Earth
have become extinct?
Rock Layers vs. Ice Cores
Which of these shows a record of
Earth’s climate and climate
changes over time?
Which of these BEST shows a
record of life and evolution on
How could you explain finding an
abundance of fossils of a species
in one particular rock layer?
Extinction event or ICE AGE
Write test using the
1. What is ______?
2. What is the main
idea of _____?
3. How does ____
compare or contrast
4. What can you infer