Thursday, 5/26/11
Warm-up:
1.
What letter comes next? Why?
A, E, F, H, I, K, L, M, N, ___
2. The pennies on the right are lying on a
table. How can you move just one penny and make both a row and a
column of 5 pennies?
Today:
- Test
- Finish Video: Einstein Revealed
- Discussion of science at BHS.
- Begin Einstein's Universe
Homework:
- Test Thursday.
- If you want to improve your rocket flight grade, make new
rockets. Launch them whenever you can (maybe a free block?)
and report your best time aloft to Mr. Stapleton.
- Complete take home portion of test
by this Friday, 5-27. E-mail it to
Mr. S. by Friday.
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Tuesday, 5/24/11
Warm-up:
- What five letter word does every Harvard graduate
pronounce wrong?
- There are three misteaks in
thi sentence. Can you find all of them?
Today:
- Video: Einstein Revealed
Homework:
- Test Thursday.
- If you want to improve your rocket flight grade, make new
rockets. Launch them whenever you can (maybe a free block?)
and report your best time aloft to Mr. Stapleton.
- Complete take home portion of test
by this Friday, 5-27. E-mail it to
Mr. S. by Friday.
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Friday, 5/20/11
Warm-up:
Imagine a speedy baseball is traveling left to right
in front of us. From our perspective, the ball is rotating
counter-clockwise. Will that rotation cause the ball to drop more
quickly or more slowly than if the ball were not rotating at all?
Do you know why?
Today:
- 2nd Rocket launch. See bottom for current standings.
- If you have made four legitimately different rockets, and none
of them have stayed aloft for 14seconds, bring that to Mr.
Stapleton's attention.
Homework:
- Study for test on Thursday
5-26.
- Complete take home portion of test
(Due next Friday 5-27).
Current Rank |
Names |
Block |
Longest
Flight (s) |
1 |
Anna Kate, Sachi |
1 |
23.9 |
2 |
Brooke, Carlos |
2 |
20.53 |
3 |
Colin, David, Sophie |
1 |
20.26 |
4 |
Alyx, Oanh, Joy |
1 |
19.58 |
5 |
My, Hung |
2 |
19.33 |
6 |
Huyen |
2 |
16.83 |
7 |
Zerrin, Lorna |
2 |
14.33 |
8 |
Ana, Clara, Lucia |
2 |
10.69 |
9 |
Tyler, Tomash, Tor |
2 |
9.53 |
10 |
Curtis, Kevin |
2 |
8.61 |
11 |
Blaize, Deniz |
1 |
8.01 |
12 |
Christy, Joy, Merima |
2 |
7.26 |
13 |
Travis |
1 |
6.9 |
14 |
Connor, Grady |
2 |
5.06 |
15 |
Jefferey, Jordan |
1 |
4 |
|
Average |
|
12.988 |
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Wednesday, 5/18/11
Warm-up: Check out the rocket
standings...
Current Rank |
Names |
Block |
Longest
Flight (s) |
Grade |
1 |
Anna Kate, Sachi |
1 |
23.9 |
101.0 |
2 |
Brooke, Carlos |
2 |
20.53 |
100.1 |
3 |
Ana, Clara, Lucia |
2 |
9.41 |
85.4 |
4 |
Blaize, Deniz |
1 |
8.01 |
83.0 |
5 |
Alyx, Oanh, Joy |
1 |
7.96 |
82.6 |
6 |
Huyen |
2 |
7.71 |
80.1 |
7 |
Tyler, Tomasch, Tor |
2 |
6.92 |
72.2 |
8 |
Travis |
1 |
6.9 |
72.0 |
9 |
Christy, Joy, Merima |
2 |
6.6 |
69.0 |
10 |
My, Hung |
2 |
6.6 |
69.0 |
11 |
Colin, David, Sophie |
1 |
5.6 |
59.0 |
12 |
Curtis, Kevin |
2 |
5.39 |
56.9 |
13 |
Jefferey, Jordan |
1 |
4 |
43.0 |
14 |
Zerrin, Lorna |
2 |
0.00001 |
3.0 |
|
Average |
|
8.537858 |
69.73388 |
Today:
- Wrap things up (see last class, below). Do you have
questions about the test review? About other stuff? Here
are some
answers to the practice test.
- Give credit for any completed practice tests.
- Test wooden projectiles (if there are any)
Homework:
- Prepare for the second (and probably final) rocket launch on
Friday. If you want a guaranteed A, this launch should bring
to four your total of "unique rockets created and launched in a good
faith attempt to achieve a 14 second flight." If this applies
to you, be sure to bring it to Mr. Stapleton's attention.
- Study for the test. Test on Tuesday.
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Monday, 5/16/11 Warm-up:
Mr. Stapleton Absent today. No Warm-Up
Today:
- Discuss
Final Project Options
- Clean a row of tables.
- Work time for test review:
in-class portion and Excel take-home portion
- Extra Credit (1% on quarter grade): "whittle" a
projectile that will travel with minimal drag and will stick,
nose-first, in a foam target when fired horizontally a distance of
20 meters.
- Rebuild rocket/parachute. The next launch
will be on Friday.
- Finish/turn in the homework that was due last
class.
Next Class:
- Be prepared to venture out into the rain. Bring necessary
rain gear. We may be launching whittled projectiles that are
brought in.
Homework:
- Finish your projectile. Bring it to next class.
- Read over the test review and be ready to ask questions next
class. The review questions and problems are indicative of the
questions and problems that will appear on the upcoming test (either
Friday or Tuesday, depending on weather and the rocket launch).
Completing the test review for credit is optional.
- Begin working on the Excel take-home test (described on page two
of
Test review)
- If your year average is not likely to be 89.5% or better, begin
working on the final project. Mr. Joppe will allow more time
when he arrives.
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Thursday, 5/12/11 Warm-up:
Suppose you have built a small boat, but it has a
problem. The boat swings quickly back and forth when you paddle.
1. Which way does it turn when you paddle on the
right?
2. How can you fix the boat so it will
"track straight," even if you paddle on one side at a time?
3.Why does your fix work?
Today:
- Turn-in your homework
- Finish building rockets.
- Take materials to alter or repair your rocket at
the launch site.
- Launch rockets and record times.
- Clean up the field; then clean up the room.
Homework:
Reflect on your rocket's performance. Devise a plan for
improving your rocket. You will have work time on Monday.
The next launch day (Wednesday, 5/18) will be short, so do not expect
work time.
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Tuesday, 5/10/11 Warm-up:
A rocket and its parachute have a total mass of 200g.
When fully deployed, the parachute has a circular cross-sectional area
with a radius of 0.4m and a Cd of 0.8. The density of
the ambient air is 1.2kg/m3.
1. Assuming that the parachute is fully
deployed, how long will it take the rocket to fall, vertically, a
distance of 50 meters?
Today:
- Build your rocket. All parts of the rocket
must remain connected during flight. Timing stops when the
first non-water portion of your rocket hits the ground.
- Measure your rocket's mass for use in the
homework calculations. Estimate its cross-sectional area.
Homework:
- Provide a reasonable value for your parachute's Cd.
Where did you find that value?
- Estimate a reasonable estimate of your deployed parachute's
cross-sectional area. Explain how you arrived at that
estimate.
- Use your estimates from 1-3, and the mass that you obtained
during class (or an estimate) to determine your rocket's terminal
velocity after chute deployment.
- Use the
rocket simulator to estimate the height of your rocket
and its time aloft at the moment of parachute release.
Use a rocket Cd of 0.3, and a density of air equaling
1.2kg/m3. This involves guessing how far the
rocket will fall before its parachute is fully deployed.
- Use your previous answers to calculate your rocket's expected
total time aloft.
Rocket
Guidelines
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Friday 5/6/11 Warm-up:
You can turn a potato gun into a rocket engine by
shooting it backward and letting it propel you forward. The force
of thrust will be PA.
Alternatively, you can use a fluid for your
propellant, instead of potato. If a fluid is coming out of the
same pipe with the same pressure, the force of thrust is 2PA (twice the
thrust from an ejected potato). This is true whether the fluid is
air or water.
1. How is it possible that an ejected fluid can
provide twice as much force as an ejected solid? Why does fluidity
matter?
2. Why doesn't it matter whether the
fluid is water or air?
In light of #2, why does the amount of water in your
rocket matter?
3. Explain why a rocket with no water (all air)
will not go very high.
4. Give two reasons why a rocket that is nearly
full of water (very little air) will not go very high.
Today:
- Check potato gun homework problems. Check drag
calculations.
- Shoot potatoes and try to achieve maximum velocity.
- Discuss rockets and parachutes.
- Get a head start on the dowel whittling challenge???
Homework:
- Design a rocket with a parachute and parachute deployment
system. Search the internet for ideas regarding deployment.
- Next Class: bring materials to add a parachute and parachute
deployment system to your rocket (or build an entirely new rocket).
Have a plan, so that you can finish your rocket before
Thursday. We will be rebuild rockets on Tuesday and
(hopefully) launch on Thursday.
- Regarding your parachute design, you may want to consider
this... According to
sources, a
"real" parachute (a semi-hemispherical shape made
from a number of individual "gores") has a Cd of 1.5,
while a parasheet (a flat circle, used for a parachute) has a Cd
of 0.75. Using your knowledge of drag and your intended
parachute design, you can estimate the terminal velocity of your rocket
after the parachute is fully deployed. Then use this rocket
simulator to estimate the height at which your parachute will
(hopefully) deploy, as well as your rocket's total time aloft.
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Wednesday 5/4/11 Warm-up:
- If you throw a ball straight up into the air,
will it stay in the air longer in the real world or in a vacuum? How could you find the answer to this question?
- We have some pneumatic potato guns that may or
may not be safe. Propose a safe way to find out if they're
going to explode when we pressurize them.
Today:
Homework:
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Monday 5/2/11 Warm-up:
If all of the angles (a-d) are 45 degrees,
and the white line is 141m long, how high is the rocket?
Today:
- Get rockets ready for launch
- Launch Rockets
Homework:
- Finish Excel Spreadsheet (see homework listed for last class)
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Thursday 4/27/11 Warm-up:
If you want to model the effect of drag on a flying
object, you somehow need to incorporate a change of sign into your
model. In the Y dimension, drag is negative on the way up, and
it's positive on the way down. In Excel, you can use a conditional
formula in the form of "= if(_____, then ______, else _____)."
What could you put in the blanks?
Tallest known
tsunami
Today:
- Check Homework
- Build Rockets
- Work on Excel Spreadsheet
Homework:
- Rocket launch next class -- weather permitting. You will
have a little time to finish your rocket before we go out. The
baseball field will probably be wet, and it may be raining a little;
dress appropriately.
- Due next Wednesday (May 4th): (Use this
template to create an Excel file that will graph the trajectory
of an object that is flung in the air. If your spreadsheet is
set up correctly, it should look like the one below. Notice that Y
drag starts out negative and then turns positive as soon as the
velocity becomes negative. To do that, I used a conditional
formula. A conditional formula .." = if(velocity>0,negative
drag, positive drag)" I didn't use the word "velocity;" I
referred to the current velocity cell. I didn't use the words
"positive drag" and "negative drag," I put in the calculations that
would give me drag, and in the case of "negative drag" put a minus
sign in front of the formula.
Object Drag Coefficient (Cd) |
0.3 |
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Object Cross-Sectional Area (m^2) |
0.0043 |
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Terminal Velocity (m/s) |
39.783003 |
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Density of Air (kg/m^3) |
1.2 |
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Mass of Object (kg) |
0.125 |
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Initial Velocity (m/s) |
40 |
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Launch Angle (degrees) |
35 |
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Time Increment (s) |
0.4 |
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time (s) |
Y Velocity (m/s) |
X velocity (m/s) |
Y drag (N) |
X Drag (N) |
Y Net Force (N) |
X Net Force (N) |
Y Acceleration (m/s/s) |
X Acceleration (m/s/s) |
Y position (m) |
X position (m) |
0 |
22.94305745 |
32.76608 |
-0.40742 |
-0.83098 |
-1.6324211 |
-0.83098 |
-13.05936902 |
-6.647830982 |
0 |
0 |
0.4 |
17.71930985 |
30.10695 |
-0.24302 |
-0.70158 |
-1.4680158 |
-0.70158 |
-11.74412665 |
-5.612604658 |
8.132473 |
12.57461 |
0.8 |
13.02165919 |
27.86191 |
-0.13124 |
-0.60085 |
-1.3562422 |
-0.60085 |
-10.84993786 |
-4.806762233 |
14.28067 |
24.16838 |
1.2 |
8.681684044 |
25.9392 |
-0.05834 |
-0.52078 |
-1.2833376 |
-0.52078 |
-10.26670118 |
-4.166239105 |
18.62134 |
34.9286 |
1.6 |
4.575003572 |
24.27271 |
-0.0162 |
-0.45601 |
-1.2412003 |
-0.45601 |
-9.929602632 |
-3.648105371 |
21.27267 |
44.97098 |
2 |
0.603162519 |
22.81346 |
-0.00028 |
-0.40283 |
-1.2252816 |
-0.40283 |
-9.802252681 |
-3.222652268 |
22.30831 |
54.38822 |
2.4 |
-3.317738554 |
21.5244 |
0.00852 |
-0.35859 |
-1.2164803 |
-0.35859 |
-9.731842247 |
-2.868753379 |
21.76539 |
63.25579 |
2.8 |
-7.210475452 |
20.3769 |
0.040241 |
-0.32138 |
-1.184759 |
-0.32138 |
-9.478071999 |
-2.571030837 |
19.65975 |
71.63605 |
3.2 |
-11.00170425 |
19.34849 |
0.093683 |
-0.28976 |
-1.131317 |
-0.28976 |
-9.050535822 |
-2.318062349 |
16.01731 |
79.58113 |
3.6 |
-14.62191858 |
18.42127 |
0.165482 |
-0.26265 |
-1.0595184 |
-0.26265 |
-8.476147286 |
-2.10121195 |
10.89259 |
87.13508 |
4 |
-18.01237749 |
17.58078 |
0.251121 |
-0.23923 |
-0.973879 |
-0.23923 |
-7.791031959 |
-1.91384716 |
4.365729 |
94.33549 |
4.4 |
-21.12879028 |
16.81524 |
0.345534 |
-0.21885 |
-0.8794664 |
-0.21885 |
-7.035731579 |
-1.750802563 |
-3.4625 |
101.2147 |
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Tuesday 4/26/11 Warm-up:
- Describe two fundamentally different ways to make
a rocket's flight stable (no including making it spin).
- Explain how each method works, in terms of CM and
CP.
- List all of the factors that you think might
affect the force of drag (air resistance) acting on a flying object.
Today:
- Intro to drag equation. Drag practice problems.
- Start building rockets.
Video showing how to do the practice problems. If you need a
copy, click the link below, under "homework."
Homework:
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Friday, 4/15/11 Warm-up:
- Have you ever thrown a hammer?
- Have you ever caught a hammer that somebody
threw?
- Why is it especially challenging to catch a thrown hammer?
Today:
Homework:
- Bring your 2-liter bottles and other necessary rocket materials to class on the
Tuesday after break.
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Wednesday, 4/13/11 Warm-up:
Explain how to steer a sled.
Today:
- Return Tests
- Rocket Stability/Steering
Homework:
- Obtain at least two clean 2-liter plastic bottles, and bring
them to class. We will be using them to create water rockets.
The first goal will be to create a 2-liter rocket with the lowest
possible force of drag.
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Monday, 4/11/11 Warm-up:
- What causes lightning?
link
- This morning -- warm front or cold front?
link
- Why does an amber filter appear amber?
Today:
- Test. If you are looking for stuff
to help you study, see last class, below.
- Rocket Stability/Steering
Homework:
None |
Thursday, 4/7/11 Warm-up:
- What sort of pressure center has moved into our
region -- high pressure or low pressure?
-
Suppose
you have cut four wooden Ws out of plywood. The drawings below are
unfinished perspective drawings. How can you complete each drawing
so that the wooden object appears to be observed along the direction
indicated by its associated arrow?
- What's the connection to climate map drawing?
- Why do Northern Hemisphere tornadoes rotate
counter-clockwise?
- Why is it currently a good thing for the people
of Asia that the Earth rotates Eastward?
Today:
- Wrap-up Climate/Weather Stuff. Block 1: finish
reviewing weather/climate questions and finish video.
Block 2: check and review homework.
Monday: Test. Then begin unit on pressure-powered projectiles traveling through the
air
Homework: Study for Monday's test.
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Tuesday, 4/5/11
Warm-up:
- Yesterday, the weather forecast included possible thunderstorms
for some areas. Was that prediction based on an approaching
warm front or an approaching cold front?
- The diagram below shows a river that is flowing to the left.
The depth of the river is the same at all points. At which
point is the current the fastest?
- Why does Mt. Washington have such fast winds?
- Why don't diesel engines need a spark plug? Why do they
sometimes need glow plugs?
http://auto.howstuffworks.com/diesel1.htm
- How is diesel fuel different from gasoline?
Today:
- Wrap-up Climate/Weather Stuff. Block 1: discuss homework;
finish video and weather/climate questions. Block 2: check
homework; complete practice map B; answer weather/climate questions;
review.
Next Class: Begin unit on pressure-powered projectiles traveling through the
air
Homework:
- Blocks 1 and 2: Study for Monday's test. What's on the
test: 1) complete a map showing the major climate features of a
fictitious continent. 2) climate/weather questions
- Block 2: Complete Weather/Climate Questions 1-14.
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