NOVA: Hunting the Elements
Part 2: Chemistry of Life, Rare Earth Elements, and Radioactivity
Elements of Life
1.
List the six most common elements of life and a common object they are found in.
Element
Symbol
Element Name
Common Object
Percent in the Body
C
Carbon
H
Hydrogen
Water
9.5%
N
Nitrogen
Fertilizer
3.2%
O
Oxygen
Water
65%
P
Phosphorus
Urine
0.4%
S
Sulfur
Charcoal, Graphite
matches, car tire
2. What can happen when excessive trace elements are lost from the body?
You can get muscle cramps
3. Describe a body function or part that utilizes each of these trace elements:
a. Calcium – Bone Strength/Density
b. Iron – Helps carry oxygen in the blood
c. Potassium – nervous system function
d. Zinc – energy metabolism
e. Magnesium – energy metabolism
f. Sodium – nervous system function
18.5%
0.3%
4. What conditions did the earliest bacteria need for energy production?
Extremely Hot Water
5. What do cyanobacteria use for energy production? What do they release as waste?
Cyanobacteria use sunlight and water to produce energy and release oxygen as waste.
6. In the core sample collected from Yellowstone, which layer is the cyanobacteria?
The thin green layer at the top of the sample
Origin of the Elements
7. What is the origin of hydrogen, the smallest element?
Made during the "Big Bang"
8. Describe the process of fusion and how it produces helium.
Process that forces two hydrogen atoms to merge to form one helium atom. (turns mass into energy)
9. What happens when a star runs low on hydrogen fuel?
Stars begin to fuse helium into larger (greater atomic number) elements - up to iron.
10. What is created in supernova explosion?
Elements heavier than iron are created
Silicon and Glass
11. What elements is sand made of?
Silicon & Oxygen
12. What is added to Gorilla Glass to make it stronger than normal glass?
Metals like sodium, potassium, and aluminum are added to the glass.
Rare Earth Elements
13. Where do most of the rare earth elements come from?
98% of Rare Earth elements come from China
14. How are the fifteen rare earth elements chemically similar?
They all have identical outer electron shells
15. What elements are rare earth magnets usually made of?
Iron, boron, and neodymium
16. Why are rare earth elements in such short supply?
Rare Earth elements are hard to separate and new uses are increasing the demand.
17. How do sharks react to rare earth metals?
Sharks are repelled by rare Earth metals
18. Describe the following parts of the lemon shark experiment:
Independent Variable – Material used (metal)
Dependent Variable – Shark's Reaction (repelled or not)
Experimental Group – Samarium (rare earth metal) + tuna
Control Group – Lead (metal) + tuna
Carbon Isotopes
19. What is the difference between the compositions of these carbon isotopes?
Protons
Electrons
Neutrons
Carbon-12
6
6
6
Carbon-13
6
6
7
Carbon-14
6
6
8
20. What happens to Carbon-14 over time?
Carbon-14 breaks down or "decays" into nitrogen when one of it's neutrons turns into a proton and
the atoms loses an electron.
21. Define radioactive half-life:
The time is takes for half of a radioactive element to decay or breakdown
22. Based on carbon dating, how long ago did the tree die?
150 years ago - used to understand climate change
Nuclear Radiation
23. Give the number of subatomic particles in uranium:
a. Protons – 92
b. Neutrons – 146
c. Electrons – 92
24. How is the mousetrap simulation similar to a fission chain reaction?
The mousetraps represented uranium atoms, and the ping-pong balls represented free neutrons
25. What element was used as fuel for the “Little Boy” bomb?
Uranium-235
26. What element was used as fuel for the “Fat Man” bomb?
Plutonium
27. The scientists at Lawrence Livermore Lab have been able to produce 6 new, synthetic elements. Why
isn’t there yet a practical use for these elements?
The atoms are so unstable they decay almost instantly.