SNC 3MO LESSONS


Unit 4: Science and Space (21 hours)
This unit develops students’ understanding of the space environment and the effects of micro-gravity on space exploration. Students explore the human and technological benefits, and the limitations, of developing technologies for use in space, or of using existing technologies in space. They also demonstrate safe use of scientific equipment to explore qualitatively the differences in space of various processes and of the behaviour of various materials.
DAY #5

Mass vs. Weight

Mass = the amount of matter in an object
Weight = (based on Newton’s 2nd Law) of an object is equal to the force of gravity acting on an object
Weight = force of gravity (Fg) = mg

[Remember:  9.8 N/kg = 9.8 m2/s2]
Example:
What is the weight of a 5.5kg turkey on Earth?
Fg = mg
= (5.5kg)(9.8 N/kg [down])
= 54 N [down]

Homework:
Practice Questions pg 84 #16(a), 16(c), 17(a), 18
 

Newton’s Law of Universal Gravitation

In 1687 Newton published a paper to describe the relationship the objects have in the solar system.  He called this affect of gravity throughout the universe the law of universal gravitation, which can be written as:

FG = [Gm1m2] ?d2
Where…
FG = force of gravity between 2 objects (N)
G = universal gravitation constant = 6.67 x 10-11 Nm2/kg2
m1= mass of object #1 (kg)
m2 = mass of object #2 (kg)
d = distance (m)
[don’t forget your rules of scientific notation e.g. 1000 = 1.0 x 103)

But, this equation assumes…
(1) At least one of the objects must be very large force of attraction to be noticeable (e.g. Earth and Moon).
(2) Only applies to 2 spheres, whose sizes are much smaller than their separation distance OR to a small object and a very large sphere.
(3) This force diminishes rapidly as the two objects move apart.

Example:
Determine the magnitude of the force of attraction between 2 uniform metal balls, of 4.00kg, used in women’s shot-putting, when the centers are separated by 45cm.
FG = [Gm1m2] ?d2
FG = [(6.67 x 10-11 Nm2/kg2)(4.00kg)(4.00kg)] ? (0.45m)2
=(2.668 x 10-10 Nm2/kg)(4.00kg) ? 0.2025m2
=1.0672 x 10-9 Nm2 ? 0.2025m2 (OR 0.000000001 ? 0.2025)
= 5.27 x 10-9 N
Therefore the attraction between them is extremely small.
 
 

This law can be applied to the Earth, for example the force of gravity on a satellite.

Homework:
Practice Questions pg 143 #8, 9, 11(a)  

Day #6
Circular Orbits

Satellites are objects or bodies that revolve around another body, such as the Moon, which travels around the Earth in an orbit.  All our satellites undergo free falling towards the Earth because of gravity and circular motion.  The Moon never hits the ground because it travels at a constant speed that keeps it at approximately the same distance, called the orbital radius, from the Earth’s centre.

There is a gravitational field surrounding objects in space, and the force of gravity acts on this so we can apply the law of universal gravitation (FG = [Gm1m2] ?d2].
 

ACTIVITY:  Marble in a Cup
*take a styrofoam cup and poke 2 holes in either side
*tie a string through the holes and tie a knot at the top (see diagram below)
*the length of the string from the knot to the end should be 60cm
*place a marble (or small object in it) and swing in a circle
*find the minimum amount of constant speed for the object to stay in the cup
*count how many times the cup makes a circle in 30 seconds
*now fold the 60cm string in half and repeat
*you should get different numbers—explain why
 

Day #7     Artificial Gravity
 

Earth    Elevator    Drop Zone
Weight = mg   (moves slower than gravity)  freefalling (a = 9.8m/s2)
weight < mg    weight = “0”

[apparent weight = the net force exerted on an accelerating object in an noninertial frame of reference]
When people are in space they are “weightless” (apparent weight is zero) because their body is in constant freefall.  Freefall is the motion of a body when only the force of gravity is acting on it.  This condition of constant freefall has been given various names:  zero gravity, microgravity and weightless.

Absence of forces on the human body affects different parts of the body, including:  muscles, bones, body fluids, heart, head, legs and kidneys.

The best way to deal with this is to design spacecrafts that have artificial gravity, where the apparent weight of an object towards the centre is similar to its weight on Earth.  For example, the spacecraft could be constantly rotating, which is similar to swinging a bucket of water in a vertical circle (centripetal & centrifugal forces).
 
The force of swinging the bucket must be greater than the force of gravity or the water will fall out.  The water is considered to be “weightless” at the top of the circle.  As well, astronauts are placed in apparatus that spins in circles to prepare them for the forces they will feel in orbit above the Earth.
 
 

DAY #8 and #9
ACTIVITY:  Egg Drop
*students can use as many straws and tape as they wish
*object is to build a contraption that will allow an egg to “survive” a drop
*cannot tape the egg or tape it into the contraption
*teacher must be able to see if the egg has “survived” after each drop
*the first drop will start at 1m
 

DAY #11

Practice Questions:

Table 8-1 Average Pressures at Various Elevations

Elevation (m)
 Pressure (kPa)

0
 101.3

1500
 85.0

3000
 70.0

5500
 50.0

9000
 30.0

12500
 20.0
 
 
 

(1)               In the CN Tower in Toronto, Ontario, the elevator takes only 60s to rise to the main observation deck, 342m above the ground.  If a person’s eardrums are forced to curve during the ascent, would they curve inward or outward?  Explain. (The curving is what causes the ears to “pop”.)

(2)               A certain weather report indicates that in 6.0h the atmospheric pressure has fallen from 100.7kPa to 100.1kPa.  What prediction can be made about the weather?

(3)               Suppose that at sea level a student is able to suck water up a straw to a height of 110cm.  If the same student tried this experiment with the same straw at the top of a high mountain, would the water rise to a level higher or lower than 110cm?  Explain.

(4)               Both gases and liquids are fluids.  Why is it not possible to use a gas to operate a hydraulic press?

(5)               Based on your past experience, discuss whether the liquids named below have a high or low viscosity.

a.       skim milk

b.      liquid honey

c.       whipping cream

d.      methyl alcohol

(6)               Describe what you think is meant by the following:

1.      As slow as molasses in January (Molasses in the syrup made from sugar cane).

2.      Blood runs thicker than water.

(7)               Common sense tells us that two flags blowing in the wind within close proximity of one another should face the same direction.  However, as you can see in Figure 9-7, this is not always the case.  Here, the wind is blowing from right to left, around the building.  Using a diagram, explain why the flags are facing opposite directions.
 
 
 

(8)               Discuss the types of features used on each of the following types of vehicles to reduce drag (i.e. air resistance or turbulence).

1.      trailer-trucks

2.      spacecraft

3.      motorcycles

4.      trains

(9)               Activity:  Obtain a piece of paper about 10cm by 20cm.  Hold the short edge of the paper above your mouth and blow under the paper to try to lift it.  Now place the piece of paper below your mouth and blow again.  Explain your observations.

(10)           Explain the following statements in terms of Bermoulli’s principle.

1.      As a convertible car with its top up cruises along a highway, the top bulges outward.

2.      A fire in a fireplace draws better when the wind is blowing outside.

 DAY #12                                            
Buoyancy
 
 

Buoyancy is the force that pushes upward on objects in fluids, causing the objects to seem lighter.  For example, weather balloons are help up by the air.
 
 

The pressure (i.e. force) underneath the object is greater than the pressure at the top surface, so the object “floats.”
 
 

Example:
 
 
 
 
 

Example:

The reason why large cargo ships do not sink is because of the shape.  The average density of the air in the ship, the metal, and cargo combination is less than the density of the water, so the ship floats.
 
 

Example:

Fish swim bladders—an organ in the middle of the fish that takes in air and releases air to change the buoyancy of the fish.  Therefore, the fish can change their depths in the water (i.e. float or sink).

 

DAY #13
Design Your Own Buoyancy Lab

* students are given thread, ruler, different size weights, bucket, water

* students must design a lab to test the strength of thread in water vs. air (Hint:  buoyancy of water will push the weights upward, so the weights will feel lighter)

DAY #14-15
Space Video

DAY #16
 

Test your Knowledge…

1)      Name the 1st man on the moon?  Year?

2)      What is the name of the USA space program location & name?

3)      What is the name of the Canadian Space program?

4)      What is the name of the 1st Canadian in space?

5)      What is the name of the 1st Canadian woman in space?

Canadian Space Program
·        John Chapman is considered the “father” of the Canadian space program (a space centre in Quebec is named after him)

·        NAE (National Aeronautical Establishment) of the NRC (National Research Council of Canada) began the Canadarm project in 1974

·        In 1981 was the 1st flight with the Canadarm (made on the 2nd USA shuttle flight)

·        1 year later the Canadian astronaut program was born

·        In 1984 six candidates were named to the Canadian Astronaut Program

·        Dr. Marc Garneau = 1st Canadian astronaut to go into space (Oct 1984--Challenger)

·        Dr. Roberta Bondar = 1st Canadian woman astronaut to go into space (Jan 1992--Discovery)

·        (others include Steave MacLean, Rober Thrisk, Bjarni Tryggvason and Ken Money)

·        1989—formation of CSA (Canadian Space Agency)

·        Currently the Institute for Aerospace Research (under the NRC)

DAY #17
Spaceflight & the Human Body
 

Bones & Muscles

·        muscles attached (by tendons) to the bones in the legs and torso (i.e. mid-section) help keep you upright against gravity

·        both muscles and bones become altered in space because the body no longer requires support

·        BONES

·        (A) lose calcium (mostly from legs & backbone)

·        (B)  loss eventually stops, but they are weak and may break when they return to Earth

·        MUSCLES

·        (A)  atrophy = muscle loses protein & becomes smaller

·        (B)  this happens in space because muscles no longer do any work to support the body (i.e. quickly break down)

·        Prevent by using exercise machines that provide a resistance for the muscles to work against

OTHER EFFECTS:  nausea & disorientation (i.e. “space sickness” because in constant free fall and no gravity for inner ear); headache; loss of appetite; congestion; “puffy head”; “bird legs”; fluid loss (i.e. increased urination)

The heart pumps blood to the head (to go against gravity on Earth).  In space there is no gravity, so the blood accumulates in the head (“puffy head”) and leaves the legs (“bird legs”).  The increased volume in the head causes the body to respond by urination, so the blood volume and red-blood-cell count decreases.  Fluids and exercise help minimize the problem.

Spacesuits = Extravehicular Mobility Unit (EMU) = 12 million US $
 

Details of Activities
Act. 4.1.1 Introduction to End-of-Unit Task (and make reference to Final Assessment Tasks)
Act. 4.1.2 Discussion/research: Review the cost/benefit analysis. Student Activity: conduct a simple cost/benefit analysis. (e.g., car vs. bus)
Act. 4.1.3 Discussion/research: how does it apply to space exploration?
Direct (monetary, communication) vs. Indirect (environment, space age materials, societal implications)
Act. 4.1.4 Begin a cost/benefit analysis of International Space Station with reference to Canadian contributions, and with a view to the components of the End-of-Unit Task
Assessment: Design of cost/benefit analysis (checklist) (Inquiry, Making Connections)

Act.4.2.1 Escaping Gravity: Why are space vehicles launched as close to the equator as possible? Discussion/research
Act.4.2.2 Newton’s Laws of Motion: What stops/starts an object?
Student activity: application of force (e.g., air track)
Qualitative analysis of relationship among force, mass, and acceleration. Action/Reaction (Spring loaded cart activity)
Act. 4.2.3 Newton’s Law of Universal Gravitation: What holds us on the Earth?
Qualitative analysis of: F=Gm1m2/d2
How could we possibly reduce the strength of gravity? (micro-gravity and “weightlessness”)
Act. 4.2.4 Free Fall: What is the effect of elevator motion on the time required for an object to fall a fixed distance? (Student Activity)
Act. 4.2.5 Free Fall: What is the effect of free fall on the shape of a fluid? (Stroboscopic observation of a thin stream of water droplets)
Assessment: Quiz/ laboratory report (Knowledge, Communication)

Act. 4.3.1 Water Free Fall—Continue from 4.2.5
Why did water take on a spherical shape?
Review of chemical bonding types, specifically surface tension.
Act. 4.3.2 Effect of Temperature on Fluids
- observe the resulting viscosity of a shallow container of oil left on dry ice
(Caution: safety concerns)
- time a dropped ball bearing in several graduated cylinders of oil at different temperatures.
- use melting point tubes to examine capillary action of fluids at different temperatures.
Explain how these examples can be applied to an everyday technology.
Act. 4.3.3 Investigation: growth of crystals on Earth.
Space Station Crystallization: compare and contrast crystal growth in micro-gravity and on the Earth (Internet research: NASA).
Act. 4.3.4 Research and brainstorm materials used in the home and for recreation that were developed for use in space.
Act. 4.3.5 Effect of Micro-gravity on robotic arm.
Simulation: How much mass can a string lift in air vs. under water? (Student Activity)
Act. 4.3.6 Limits of Materials
What is the effect of extreme changes in temperature on materials? Demonstration of putting hot glass under cold water. (Caution: safety concerns) Explain how this could be applied to an everyday technology.
Assessment: Oral report on the behaviour of materials in space. (Inquiry, Communication, Knowledge)

Act. 4.4.1 Research/brainstorm the effects of lift-off, long-term habitation in space, re-entry and landing on the human body.
Act. 4.4.2 Activity: “puffy-head, bird’s-legs syndrome”
Act. 4.4.3 Monitoring and Maintaining the Body: What probes are used to monitor human systems? What diets, exercise equipment and exercise regimes are used in space and why? (Newton’s Laws/Universal Gravitation)
Research/brainstorm/reflect/discuss
Act. 4.4.4 Astronaut waste: What happens to human waste? Disposal considerations?
Brainstorm/research/discuss
Assessment: Written report on the effect of space travel on the human body (rubric) (Communication, Making Connections)

Act. 4.5.1 Review and revise the cost/benefit analysis begun in Activity 4.1 in the light of Activities 4.2-4.4. The analysis includes references to the impact of space research and technologies on society, the challenges associated with human survival in space and how they are addressed.
Assessment: Oral report on revised cost/benefit analysis (rubric) (Knowledge, Inquiry, Communications, Making Connections).