1. Sunken Treasure Project*
Physical Science
Sunken Treasure Project*

2. What title will you choose?
In the realm of ClassCraft, you must discover the treasure that is found in a sunken city
*NOTE: If you are not participating in ClassCraft, feel free to name this SCUBA diving project
You are given a special helmet that allows you to see underwater as well as a special backpack that allows you to breathe underwater for a short time
The time depends on the person and the depth

3. Can’t hold your breath
Your backpack holds the equivalent of 2200 L of air
The average person breathes 1 L of air with each breath
To determine how long your air will last, you must first determine how long it will last above water

4. How long will the air last
To find out how many breathes you take each minute
With a partner, breath normally for one minute and count the number of breathes you take
Do this at least three times and take the average
Multiply the average times 1 L
This tells you the amount of air per minute that you would breathe

5. How long will the air last…you?
Now you need to know how long the air would last ABOVE the water
Divide the amount of air in the tank by YOUR air per minute .
Example: A person breathes an average of 20 breathes per minute
20 x 1 = 20 L of air per minute
2200/ 20 = 110 minutes of air (above water)

6. Freshen up a bit
Above the water, you have one atmosphere of pressure above you
As you dive deeper, there is more and more water pressure adding to the air pressure
The amount depends on the depth and the type of water
In freshwater, every 33 feet of depth equals 1 atm of air
If you dive 33 feet, there is 1 atm of water and 1 atm of air = 2 atm
If you dive 66 feet, there is 2 atm of water and 1 atm of air = 3 atm
In saltwater, the water is heavier (from the salt), so you don’t have to dive as deep to increase the pressure

7. (Not) in the salty air
In saltwater, every 30 feet of depth equals 1 atm of air
If you dive 30 feet, then there is 1 atm of water and 1 atm of air= 2 atm
If you dive 60 feet, then there is 2 atm of water and 1 atm of air = 3 atm

8. How to determine how much pressure for a depth
For any depth, to determine the amount of pressure
Saltwater: depth/30 + 1
Freshwater: depth/33 + 1
This will be important later

9. Planning Factor
The treasure is inside a sunken building inside a sunken city
The city was near the sea when it slid it became submerged.
That means, you should plan for a salt water dive

10. TREASURE MAP
Start Point X

11. How long will it take you to swim?
You determine that your swim speed is 25 feet per minute
You must determine:
How long you will spend at each depth
How much air you will use at each depth
It will take you 2 minutes to pick the lock on the treasure chest OR you can swim with the whole thing at ½ speed
Next, you will need to know some measurements

12. X 20 feet Start Point 60 feet 10 feet 15 feet 30 feet
Horizontal Distances
20 feet
Start Point
60 feet
10 feet
15 feet
30 feet X

13. X Start Point Vertical Distances 10 feet 10 feet 50 feet 20 feet

14. The Plan
You must decide what route that you will take to get to the treasure
Remember, you need to maximize your air supply, so I recommend swimming on the surface for as long as you can
This will not take away from your air supply
Break your dive into stages (0 ft depth, 10 ft depth, 20 ft depth, etc)

15. The Plan, continued
Use your swim speed and the horizontal distances to determine how long you will spend at each depth
When you dive down, use the swim speed again to see how long you will dive
To be safe, use the deepest depth of that stage to figure out air usage
Any difference will be on the way back up
Speaking of, DON’T FORGET about swimming back to the start point!

16. What to turn in
Take the map slide (slide #10) and sketch out your dive route
Label the distance and time for each segment as well as overall time
Show the breathing test that you did with your partner
Number of breathes for each minute and the average number of breathes per minute
The average amount of air per minute
Fill out the data table

17. Data Table Stage Depth (ft) Distance (ft) Time (minutes)
Pressure (atm)
Air Used (L)
Air Remaining (L)
Calculation

18. Data Table
Segment is for each swimming section that you do there AND back
On my example it would appear that I would have 7 segments (3 down, 1 at the bottom, and 3 back up)
However, as I travel through different depths, it would have to be broken up more
ONCE AGAIN, use straight horizontal and vertical distances for easier math
There is a section for Boyle’s Law calculations

19. Boyle’s Law calculation tips
If you compare everything to the surface, it will be easier
P1 = 1 atm
V1 = 2200 L
P2 = Depends on the depth
V2 = this is what you will calculate
Divide V2 by your breathing rate to get the amount of air used.

20. Example sketch
The following slide shows an example of a route that you could take
I don’t recommend it
You would be underwater longer
You will use more air
The math is more challenging (Pythagorean Theorem and all of that)
Once again, I suggest that you use straight horizontal and vertical movements instead of diagonal ones

21. X Start Point 76 feet; 3.04 minutes Total Time: 13.68 minutes

22. WARNING
Don’t forget that the deeper you go, the faster your air will be used
At 60 feet, you are using air 3 times as fast as on the surface
So, if you spend 2 minutes at the bottom, you will use more than 6 minutes of air
Why more? Because it is deeper than 60 feet!

23. ClassCraft rewards
For those of you NOT doing ClassCraft, this is a project grade
For those of you who are participating in ClassCraft, it is STILL a project grade. In addition, the game rewards are:
Up to 1050 XP (based on grade)
Every point over a 70 yields 15 XP
Up to 1000 GP (based on grade)
I will take your percentage grade and multiply this number for your reward

24. Grading
I will be checking your thought processes and ESPECIALLY your Boyle’s Law calculations
Initial breathing calculations: 15%
Copy of treasure map with labeled distances and times for each segment as well as overall time: 25%
Completed data table with all calculations correct: 60%