Download Mdsta Conference presentation

CHANGING MISCONCEPTIONS
IN PHYSICS AND PHYSICAL
SCIENCE STUDENTS
PRESENTED AT MDSTA
OCTOBER 29TH 2005
LAWRENCE TECHNOLOGICAL UNIVERSITY
Presenters:
Catherine Charnawskas
and
Margaret Milligan
MDSTA PRESENTATION
CHANGING MISCONSEPTIONS IN PHYSICS
AND PHYSICAL SCIENCE
OCTOBER 2005
The following presentation was made by
Catherine Charnawskas
Physics/Physical Science/Math Teacher
Lamphere High School
Madison Heights MI
and
Margaret Milligan
AP Biology/Biology/Physics Teacher
Oak Park High School
Oak Park MI
We would like to thank
Charles Garofali for use of some of his demos and labs. These labs are used with permission
and are taken from his Master’s Thesis from Lawrence Technological University.
You rock Charlie!
- Capturing Light Lab
- How far can you jump on…
- Your weight on other planets.
Some labs are modifications of activities taken from Hands-On Physics
by James Cunningham and Norman Herr
All of the following labs and handouts can be found at
http://www.msu.edu/~milliga9/mdsta
Please feel free to pass on this information with fellow teachers.
For a complete list of Physics/Physical Science Misconceptions presented in the Science Beliefs
Quiz please see the chart at the end of this handout.
2
TABLE OF CONTENTS
Topic
Page number
Website of Common Misconceptions
Newton’s Third Law
Gravity
Law of Universal Gravitation
Newton’s First Law
Circuits
Light and Human Sight
Density and Buoyancy
Chart of Physics/Physical Science
Misconceptions
Interactive Physics and Gravity
Student Handout
Your Weight on Other Planets
Student Handout
How Far can You Jump On…
Student Handout
Story of an SUV Student Handout
Newton’s First Law Student Handout
Newton’s First Law Teacher Answers
Can You Light the Bulb? Student
Handout
Color Notes Student Handout
How Do Astronomers Capture Light?
Student Handout
How Dense are You? Student Handout
Regulation of Buoyancy Student
Handout
Regulation of Buoyancy Teacher
Handout
4
4
5
5
7
8
9
11
13
3
14
16
17
18
21
23
24
26
28
29
31
33
Website of Science Beliefs Quiz:
https://www2.oakland.edu/secure/sbquiz/index.cfm
Question #14
When a book is at rest on a table (not moving), other than the force of gravity,
there are no other forces acting on it.
Answer #14
False
Topic
Newton’s Third Law
Reasoning
Newton’s Third Law states for every action there is an equal and opposite reaction.
We know that there is a force pulling down, called gravity, but most students do not
think of the other force of the table pushing back on the book, the Normal Force.
Demos
Physical Science
This is a good introduction to Newton’s Three Laws. It will cause the students to
have a couple of questions that will be answered as you go through the unit!
Have a book sitting on a table. The students will easily agree that only gravity is
acting on it. But ask the students what will happen if we didn’t have the table.
Students will correctly tell you that the book will fall. Ask them again what forces
are acting on it. They will tell you once again that gravity is acting on it. You can do
this. But then ask the students how a book under only under the influence of
gravity could be still and fall.
At some point a student will say that the table has something to do with it. Usually
they will say that friction from the table will cause it to not move. This is a good
time to explain that friction only happens when something is moving. The book on
the table is not moving.
Physical Science
To allow students to visualize what is happening in terms of equal and opposite
forces try this quick and easy demo. Have two students face each other holding
simple spring scales. Attach the scales to each other and have the students pull on
their scale. Ask the class what is happening? Why does this occur? Try several
different students of different sizes. Can a larger student out pull a smaller
student? Why or Why not?
Physics
As a twist on the above Physical Science demo, we can tie in air resistance with
Newton’s Third Law. Each student will need a textbook and a piece of paper. Have
the students hold the book out in one hand and the piece of paper in the other. As
students hold the two objects, discuss the amount of needed to keep them in place.
Students can also draw free body diagrams after the demonstration. Have
students drop both objects and observe their motion. (Book hits first, paper
floats down to ground).
4
Have the students pick up the book and piece of paper. For this trial, have them
place the paper underneath the book and drop both objects. Have students make
observations as the objects fall. What changed? Some students will say the book
is pushing the paper down rather than gravity is pulling both down with the same
force. Ask students what they could do differently to show both object should fall
to Earth at the same rate.
Have students pick up their book and paper. This time place the paper on top of
the book and drop both objects again. Ask the students what has changed. Why
does this occur? What forces are acting on the book and paper?
Physics
This demo is to help students try to visualize the forces at work using Newton’s
Third Law. Give students two skateboards, two pairs of rollerblades, or two desks
chairs with wheels and ask them to come up with their own demonstration. Once
the students develop and try their demonstration, have them explain what is going
on. Have students draw free body diagrams that show what forces are acting on
the students in the demonstration. This is a good introduction or wrap up
demonstration for Newton’s Third Law.
Questions #15
An astronaut is standing on the moon with a baseball in her/his hand. When the
baseball is released, it will fall to the moon’s surface.
Answer #15
True
Topic
Gravity/Law of Universal Gravitation
Reasoning
The Law of Universal Gravitation states that the gravitational attraction between
two objects is proportional to the masses and inversely proportional to the distance
between the objects. The moon is less massive than the Earth so the gravitational
attraction is less, but still very much real! The ball will fall, but at a much slower
rate.
Demo/Activity
Physics and
Physical Science
(Time: 30 min)
Have the students set up a demo using the Interactive Physics
Software. Have the students change the acceleration due to gravity to match that
of the moon. Then have the students create a ball and have it run. They will see
that the ball does in fact fall, but slowly. See the worksheet and student
instruction at the end of this packet for more information.
You can then have the students use the gravity factors of other planets and see
what happens. Which planets drop the fastest and which drop the slowest.
Demo/Activity
(Time: 30-40 min)
After the students have done the Interactive Physics activity,
you can have the students do some calculations. They can figure their weight on
other planets and how far they would be able to jump on other planets.
5
Demo/Activity
Afterwards, you should show a video clip of the first walk on the Moon. The
students will then see that even though the men need a lot less energy to walk on
the Moon and they often looked like they were going to float away, they would come
back down to the Moon. At this point, some students may ask you about the “myth”
that if you pushed too hard on the Moon you would float away. You could then tie in
a lesson on the escape velocity. You could compare the escape velocity of Earth to
that of the Moon. Discuss with the students how other activities, such as playing
golf, would be different on the Moon and other planets. There are several video
clips available of astronauts doing simple tasks on the Moon.
Physics
Another related misconception is that astronauts are weightless in space. You can
show students the following video clip that is an interesting analogy that being in
space is kind of like being in an elevator!
http://ksnn.larc.nasa.gov/videos_cap.cfm?unit=float#
To help students visualize escape speed and how a satellite is affected by gravity
try the following animation. Students will be able to see what happens as the
amount of force applied to the cannonball increases. The explaination that follows
describes how this fact first described by Newton is how we get the space shuttles
into orbit around the Earth.
http://spaceplace.jpl.nasa.gov/en/kids/orbits1.shtml
Video Clips
Looking for NASA video clips? Go to the NASA website and use the search option.
They have many of the famous clips from the Apollo missions. Below is the direct
link to the famous feather and hammer dropping experiment from Apollo 15.
http://history.nasa.gov/alsj/a15/a15v.1672206.mov
NASA Lunar Feather Drop Home Page:
http://www1.jsc.nasa.gov/er/seh/feather.html
Supplies
Interactive Physics
For a free unlimited demo go to www.interactivephysics.com or visit the Arbor
Scientific Interactive physics Software session today (session 4) for a copy of the
software and more information on the program.
Laptops or Computers
Calculators for the students
Meter Sticks
Video of First Moon Walk
Further Exploration of Forces and Newton’s Second Law – See the Car Mass activity at the end of this
handout.
6
Question #18
A force is needed to change the motion of an object.
Answer #18
True
Topic
Newton’s First Law
Reasoning
Newton’s First Law states that an object in motion will remain
in a constant, straight line motion, and an object at rest will stay at rest, until
acted upon by an outside force.
Demo/Activity
Physical Science
(Time: 10-15 min)
Roll a bowling ball down a hallway, or between the desks. Have
the students change the direction of the bowling ball. Then ask the students what
they did to change the direction of bowling ball. They will say they pushed it.
Remind the students that a push or a pull is a force.
You then can have the students give the bowling ball motion. Ask them once again
how they did that. They will tell you it was a force.
Physics and
Physical Science
Students often have a hard time visualizing what we mean when we tell them about
changing or applying forces. A fun way to get students to apply Newton’s First Law
is the Penny and Hoop Demo. Have students set up a soda bottle or flask (the wider
the mouth the better usually) with an embroidery hoop balanced on the opening and
one or two pennies balanced on the hoop directly above the opening of the bottle.
Pose the following challenge to the students: Get the pennies into the bottle
without touching them.
The solution is simple, get the hoop out of the way. Quickly grab the far side of
the embroidery hoop and jerk it out from under the coins. This will momentarily
stretch the hoop horizontally, breaking contact with the stack of coins without
disturbing it. The coins then fall into the bottle. If you grab the near side of the
hoop first, you momentarily stretch the hoop vertically, so that the coins are
tossed into the air - they may or may not land in the flask.
Physics
Physical Science
Many of us have seen the famous Tablecloth Demo where the tablecloth is pulled
out from under a pile of dishes. If possible, make your own tablecloth making sure
that one edge does not have a hem and is smooth. If you do have a tablecloth, the
brown paper towels most school have works well also. Start with one beaker on
your table (or lab bench) and ask the students what they think will happen. Most
know what will happen, but don’t know why. Have them describe the motion of the
objects and ask them how this is an example of Newton’s First Law. If you
successfully demonstrate this with one beaker, begin to add more. Our class
record is eight beakers. If you are leery about student injuries, this can be done
solely by the teacher.
7
Physics
Adding Inertia
Inertia is often taught hand in hand with Newton’s First Law. Students often have
hard time defining inertia because they can not “see” it. This simple lab allows
students to use their knowledge of motion and forces.
Cut out a fourth of an aluminum pie pan. Place a marble or other round object
inside the pie pan and give the marble a quick push so that it travels around the pie
pan. As the marble leaves the pie pan, it will follow a straight line path. See the
accompanying worksheet at the end of this handout for student directions and
applications.
This demonstration works because of the forces working on the system. Gravity is
acting on the marble in a downward direction. The marble feels a constraining
force from the pie pan and is forced to travel in a circular path rather than a
straight line. Newton’s First Law states that an object in motion will remain in
motion unless acted upon by an outside force, and this motion is a straight line
motion. Once we remove the side of the pie pan the marble will once again travel in
a straight line path. Most students will predict the marble will continue is a circle
path.
Questions #19
It is possible to light a flashlight bulb with just one wire and one battery and no
other equipment.
Answer #19
True
Topic
Circuits
Reasoning
All you need to light a flashlight bulb is a closed circuit. You can achieve this by
wrapping the stripped wire around the base of the light bulb and connecting it to
the two ends of the battery. Or you can placed the light bulb on one of the ends of
the battery and then use the wire to connect the other end of the battery to the
light bulb.
Demo/Activity
(Time: 10-15 min)
Actually give the supplies to the students and see what they
come up with. They will eventually work this out. You can then talk about a closed
circuit.
Ask students to find four ways that will light up the bulb and four ways that the
bulb will not light. Have students diagram their findings and develop their own
explanation of what is occurring and what makes a circuit. See student handout at
the end of this packet.
Demo/Activity
(Time: 10 min)
Once the students have learned about closed circuits, you can
actually have the students create a human closed circuit. Have the whole class hold
hands (it is usually best if the students stand in a circle). Insert the circuit ball
into the circle. If the connection is complete, it will light up and make noise. (look
up cost)
8
Physics
Another version of the circuit ball is the chirping Easter chicken. Many stores
carry these simple chickens around Easter time. Once a complete circuit is formed
with the two nodes on the bottom of the chicken, it will begin chirping. This is a
fun demo to use at the beginning of an electricity unit. Hold the chicken in your
hand in different ways and have the students hypothesize why it does or does not
chirp. Often students will eventually ask to hold the chicken and figure out that
electricity has something to do with it. Continue to ask probing questions until
students come up with the idea of “closing” the circuit.
Supplies
D Cell Batteries
D Cell Battery Holders
$1.00 each
#022-19316
www.cynmar.com
Wiring 24g
$14.25
#WW6364124
www.sciencekit.com
Flashlight Bulbs
Circuit Ball
Question #20
We (humans) need light in order to see.
Answer #20
True
Topic
Light and Sight
Reasoning
Our eyes have rods and cones in them. The rods are sensitive to light and dark.
Cones are sensitive to color. Without light, there is no color and there is no
light/dark.
Demo/Activity
(Time: 30-50 min)
Have the students spend one class period making the
classroom light-free. Use dark paper to cover the windows and the doors.
Students really get into this! Every once in a while, do a “Light Check.” Turn off
the lights and have the students see where light is still coming into the room.
(Time: 10-15 min)
The next day, have the students answer the question:
When you sit in a completely dark room how well will you be able to see?
Most students will tell you that “once your eyes get adjusted you will be able to see
just fine.”
Turn off the lights. Ask the students if they see anything yet. Ask them if they
were right or wrong. Some students will tell you to wait for a few minutes. You can
9
humor them for a while. Eventually turn the lights back on. Have a discussion about
what happened. Make sure to include a discussion on how the eye works.
The website How Stuff Works has a good explanation of how the eye works and
perceives light. On page three of their explanation, there is a simple animation of
what happens inside the eye when light hits the back of the eye.
http://www.howstuffworks.com and search for eye.
Demo/Activity
(Time: 15 min)
Since the room is light free, it is a good time to talk about a
couple of other things dealing with light. One of them is the addition of the colors
of light. All you need for this is colored overheads (red, blue, and green) and either
three overheads or three flashlights. I find the overheads are easier to use. You
can use the diagram (in the following pages) to have the students color what they
see and give names to the colors. To get white when you add all the colors together
is difficult (it may be pink or slightly blue). Make sure that you do a white light
added with a blue light and see what you get. The white should appear whiter. You
can explain that laundry detergents are using this technology to “make whites
whiter.”
Demo/Activity
Do on a Friday!
Astronomers Capture Light Lab. This activity also requires a light free room. Make
sure to open the shutter to get a longer shutter time. We want to take time lapse
pictures. Have the students do the lab. Then talk about what was captured on the
film. Was it the person in the background? Was it is the light and its path? You
can then point out that the only things that were captured on the film were things
that gave off light or reflected light. Students love to do this lab! They really like
to see the pictures they have created! Make sure to go through these before
giving them back to the students as a censor! You could then dive deeper into using
this for astronomy (Hubble Telescope). See the student handout “How
Astronomers Store Light” at the end of this handout.
Supplies
35mm Camera & Tripod
Pen lights and/or Laser Pointers
Black and White Film
Developing the Film
Meteor Photo & Imaging Company
1099 Chicago Rd
Troy, MI 48083
(248) 583-3090
Three Overheads or Flashlights
Colored Overheads
Crayons
10
Question #26
A ball made of solid steel will not float. However, a boat made of steel floats
because the steel is made less dense because of the way it is shaped.
Answer #26
False
Topic
Density/Bouyancy/Displacement
Reasoning
The ship’s hull is displacing water. If the substance replacing the water is less
dense it will float. If it is more dense it will sink. The ship’s hull is filled with air.
The ship’s hull is not filled with steel. You just need to make the hull large enough
to displace enough water to create a buoyant force large enough to hold up the
boat.
Demo/Activity
Using clay, make a ball. Drop it in the water. It will sink to the bottom. Take that
same clay and slow carve out an indent. Put it in the water. The larger the indent
the more likely it will be to float. Let the students continue to do this with the
challenge of how big is the smallest indent for the clay to float.
Physics
Students often do not think of density when viewing objects. They correlate size
of an object to the mass of the object. An easy way to change this misconception
is a simple demo using soda!
Have two cans of soda – one regular and one diet. Have the students observe the
cans and record the volume (listed on the can). Ask the students which can is more
dense. Most students will say they are equally dense since they are the same thing.
Drop both cans into a tank of water – fish tanks work well. The tank must be made
of glass so students can see what happens. The regular soda will sink while the diet
soda floats. Ask the students why this happens. Students will eventually come up
with the explaination that the regular soda is more dense. Take out the cans and
find their mass. Students can then calculate the density of the two types of soda.
Have students bring in several types of soda the next day to determine which soda
is the “most dense”. Further discussion can include what the densities of the sodas
are different (amount and type of sugar used). See student handout at the end of
this handout.
Demo/Activity
Using a 2-L pop bottle, a Fizz-Keeper, and ketchup packets make Cartesian Divers.
Make sure the students note that there is air in the ketchup packets before they
put them in the bottle. Have the students put the ketchup packets in the bottle
first, then fill with water. Then screw the Fizz-Keeper on top. Have the students
notice that the ketchup packets float. Then use the Fizz-Keeper to create a higher
pressure and decrease the volume of air in the ketchup packets. Have the students
look at the ketchup packets and notice the volume of air is decreased (as pressure
on a gas increases, the volume of that gas decreases – Boyle’s Law). The students
will also see that the ketchup packets have fallen to the bottom. The ketchup
packets are no longer displacing enough water to keep afloat.
11
Cartesian Divers can also be made using a 2-L soda bottle and eye droppers. See
the student handout at the end of the handout for more information.
Demo/Activity
Pennies Activity. Using pennies and film canisters, you will be able to show what
happens to a ship’s hull if there is too much steel in the bottom. As the number of
pennies increase, the buoyant force is less and less able to keep the film canister
afloat.
Supplies
Clay
Empty 2-L Pop Bottles
Ketchup Packets
Fizz-Keepers
Eye Droppers
Pennies
Film Canisters
The following activities and demos deal with densities and you can use them
separately, as an introduction to this unit, or in a unit of their own.
Demo/Activity
Density Cubes. These cubes are the same size and shape. It is a good demo for
calculating density and seeing that even if the objects are the same size and shape,
they can have very different densities.
Demo/Activity
Neutral Buoyancy. The students will need to come up with an alcohol/water mixture
in which oil will seem to float suspended in the mixture. You can then talk about
neutral buoyancy. Neutral Buoyancy is when the buoyant force and the weight are
equal. The object will be able to move around in the liquid substance without sinking
or floating to the top.
Supplies
Density Cubes
$16.25 10-cubes/with case
095-18499
www.cynmar.com
Oil
Rubbing Alcohol
12
Science Beliefs Quiz Physics Questions and Possible Topic
Question
Number
Answer
Question
Topic
14
FALSE
When a book is at rest on a table (not moving), other than the force of gravity,
Newton's 3 Laws
there are no other forces acting on it
Force and Motion
An astronaut is standing on the moon with a baseball in his/her hand.
Gravity
When the baseball is released, it will fall to the moon's surface.
Force and Motion
Force and Motion
Circuits
Electricity
15
TRUE
18
TRUE
19
TRUE
A force is needed to change the motion of an object
It is possible to light a flashlight bulb with just one wire and one
battery and not other equipment.
20
TRUE
We (humans) need light in order to see.
Light
21
FALSE
If you see your head and shoulders in a mirror, with the mirror mounted
Light and Optics
securely and flat against the wall, and you wanted to see even more of
yourself (for example, your belt) you should back straight away from
the mirror.
22
TRUE
The velocity of a radio wave and a visible light wave is the same.
Waves
23
FALSE
The total energy in the universe is constantly changing.
Thermodynamics
24
FALSE
Most things in our universe tend to become more organized and more oderly
Thermodynamics
over time.
25
TRUE
Heat flows from warmer to cooler ones until both reach the same temperature.
Heat
Energy
26
27
28
31
FALSE
TRUE
TRUE
TRUE
A ball made of solid steel with not float. However, a boat made of steel floats
Density
because the steel is made less dense because of the way the boat is
Buoyant force
shaped.
Displacement
Under normal temperature and pressure conditions, all particles, such as
Gas Laws
atoms or molecules, are in constant motion.
Kinetic Energy
A increase in temperature corresponds to an increase in the motion of
Gas Laws
the particles.
Kinetic Energy
Two containers with equal amounts of clear water are at two different
Heat
temperatures. Equal amounts of green dye are added to each container.
The dye will mix with the warmer water
faster.
Kinetic Energy
13
Interactive Physics
Gravity on the Moon
Name:
Date:
How does the gravity of the moon affect how objects fall?
Procedure
1. Open Interactive Physics on your computer. (Click OK if a Pop-up comes up about the trial version)
2. Use the task bar at the left and select the circle. In the whiteboard, click and drag to draw a circle.
Make sure your circle is towards the top of the whiteboard.
3. While you have the circle selected (right click) choose World from the top tool bar and then scroll
down and select Gravity. Use the slide bar to change the gravity to that of the Moon. (This is
approximately 1.00m/s2 for this program)
4. Choose Define from the top tool bar and then Vectors and finally choose Gravitational Force.
5. Click run on the top tool bar and observe what happens to your object.
6. Click stop and reset. Change the gravity back to Earth (This is approximately 10.00 m/s2 for this
program)
7. Draw a diagram below that represents the object on the Moon and on the Earth. Make sure to
include the vectors!
14
8. Compare the falling of the object on the Moon and the object on Earth. What did you observe?
9. Use the conversion factors below the calculate the force of gravity on other planets.
Planet
Conversation Factor
Mercury
0.38
Venus
0.86
Mars
0.38
Jupiter
2.87
Saturn
1.32
Uranus
0.93
Neptune
1.23
Eros
0.001
Force of Gravity
(in m/s2)
10. Change the gravity of your circle so that it is equal to each of the above planets. Make observations
of what happens to the object as it falls.
11. On which planets is gravity greater than on Earth?
12. On which planets is gravity less than on Earth?
13. On which planet would it be easiest to slam dunk a basketball?
14. On which planet would it be hardest to slam dunk a basketball?
15. Why is there a change in gravity depending on which planet you are on?
15
Your Weight on Other Planets __________________
Science
Directions
1) Show your work on the back. No work = No credit.
2) Multiply your weight times the conversion factor.

If you would rather not use your weight use 95lbs for your calculations.
Planet
Conversion Factor
Mercury
.37
Venus
.9
The Moon
.17
Mars
.38
Jupiter
2.6
Saturn
1.16
Uranus
.97
Neptune
1.15
Pluto
.05
Your New Weight
Questions - Use the textbooks glossary, the current chapter and the data above.
1) Weight is a measure of __________________________________________________
2) Mass is a measure of ____________________________________________________
3) Which planet has the most gravity? ____________ The least? ________________
4) Which planet is the largest? ______________
5) You will feel weight when you are near another _______________________________
6) A person living on the moon for 1-2 years upon returning to Earth will feel
________________________________________________________________
7) Astronauts on the moon were wearing spacesuits and backpacks that were over 200 Earth
pounds, considering their own weight how were they able to move around so easily?
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
16
How Far Can You Jump On…….
Science
________________
1) Find out how far you can jump (standing jump) on Earth using a meter stick.

Jump 5 times and take the average of the 5 jumps, show your data and work!
Jump #1 = _________cm
Jump #2 = _________cm
Jump #3 = _________cm
Average = ___________cm
Jump #4 = _________cm
Jump #5 = _________cm
Total = ______________
Divide the total by 5 to find the average!
2) In the data chart are the gravity conversion numbers for a number of places in the solar system,
use your jump average to determine how far you could jump on these worlds!
Divide the conversion factor into your Earth Jump Average to determine your New
Jump Distance - cm!!!!
Place Conversion Factor Jump Average (Earth)-cm
New Jump Distance-cm!!
Moon
.17
______________
____________
Mercury
.38
______________
____________
Venus
.86
______________
____________
Mars
.38
______________
____________
Jupiter
2.87
______________
____________
Saturn
1.32
______________
____________
Uranus
.93
______________
____________
Neptune
1.23
______________
____________
Eros
.001
______________
____________
17
Name:
Date:
Class Period:
Story of an SUV
Part I
We are going to figure the mass of Miss Charnawskas’s SUV. The first thing that we need to do
is draw a FBD of all the forces on the SUV.
What causes acceleration? ______________________
What is the equation for force? __________________
With the information about the forces and the acceleration we will be able to calculate the
mass of the SUV. Fill in the chart below:
Force of the first scale: ___________________
Force of the second scale: _________________
Force of the third scale: __________________
Length of the Time Interval: _______________
18
Time Interval
Number
1
2
3
4
5
6
Distance Covered During
the Time Interval
Total Distance Covered
Show your work below and solve for the acceleration of the car. (Hint: It would help to solve
for the final velocity first using the last two time interval readings)
19
Part II
BUT WAIT!!!! We’re not done! What about the other force?
Which force have we calculated? _________________________
Which force do we still need to figure before we can calculate the mass of the SUV?
_________________________
How do you think we will go about doing this? _____________________
The force of friction will equal the thrust force when ________________
What is the total force of the bathroom scales while the SUV is moving at a constant velocity?
_________________________
What is the net forces on the SUV? ________________________
What is the acceleration of the car from part one? _____________
What is the mass of the SUV? ______________________
20
Newton’s First Law
and Inertia
Name:
Date:
Question: How does Newton’s First Law work and what role does Inertia play?
Materials
- Pie Pan
- Marble
Procedure
1. Cut out one fourth of your pie pan so that it looks like the diagram to the right.
Be careful not to distort the rest of your pie pan or cut yourself! Wear work gloves!
2. Place the marble inside the pan as shown. Once the marble is in motion, it will
follow the path around the outer edge of the pie pan.
3. Using the diagram at the below, predict the path of the marble once it leaves the pie pan at location
X. DO THIS BEFORE PUTTING THE MARBLE IN MOTION!!
4. Give the marble a quick push so that it is traveling around the pie pan. Observe the marble as it
travels around the pan and on the diagram below show the actual path of the marble. Answer the postlab questions on the backside.
21
Post-Lab Questions
1. How was Newton’s first law demonstrated in part of this experiment?
2. Describe centripetal force and explain how it keeps the marble moving in a circular path while in the
pan.
3. In what direction does the marble move after leaving the pan? Why
4. Suppose you are swinging a weight on the end of a rope around your head in a counterclockwise
direction. The rope is suddenly cut when the weight is directly in front of you. Where will the weight
travel? Where would you tell your friends watching you not to stand? Draw a diagram that shows what
is happening.
22
Answer Key for Newton’s First Law and Inertia Lab
1. How was Newton’s first law demonstrated in part of this experiment?
Movement of the marble. It started at rest and remained at rest until it was flicked by the
student. This was the addition of an outside force. The marble continued to be in motion until
the force of friction overcame its motion and the marble stopped.
2. Describe centripetal force and explain how it keeps the marble moving in a circular path while in the
pan.
Centripetal force is exerted by the pan on the marble. This is just like when a heavy object is
tied to a string and swung in a circle. In that case, the string exerts the centripetal force on the
heavy object.
3. In what direction does the marble move after leaving the pan? Why
The marble will move in a straight-line path after exiting pie pan. There is no more centripetal
force from the pie pan on the marble. The marble will move in a path perpendicular to the line
from the center of the pan to the edge at which point the marble exited.
4. Suppose you are swinging a weight on the end of a rope around your head in a counterclockwise
direction. The rope is suddenly cut when the weight is directly in front of you. Where will the weight
travel? Where would you tell your friends watching you not to stand? Draw a diagram that shows what
is happening.
Just like the marble and the pan, the weight will move in a path perpendicular to the line from the
center of the person to the point where the rope was cut.
23
Can you light the bulb?
Name:
Date:
Question: How many ways can you light the bulb using only a battery and a piece of wire?
Materials
- Flashlight lightbulb
- Wire
- D battery
Procedure
1. Using the above materials, create four different arrangements in which you are able to light the
lightbulb. Draw your arrangements below and label each part.
Arrangement One
Arrangement Two
Arrangement Three
Arrangement Four
24
2. Now crate four arrangements in which the light bulb does not light, even though all of the materials
were used. Draw your arrangements below and label each part.
Arrangement One
Arrangement Two
Arrangement Three
Arrangement Four
3. Develop your hypothesis that explains what is required to light the bulb.
25
Colors of light
Notes
Primary Colors of Pigments:
____________________
____________________
____________________
Primary Colors of Light:
____________________
____________________
____________________
_______________ + ________________ = ______________
_______________ + ________________ = ______________
_______________ + ________________ = ______________
______________ + ________________ + ______________ =
26
________________
_________
________
____________
____________
________
27
Science
PURPOSE
Lab - How do Astronomers Store Light?
___________________
Discover how astronomers are able to store light from distant stars and galaxies.
MATERIALS
35mm Camera & Tripod
Pen lights and or Laser Pointers
One light tight room (Dark)
Film and or Digital Images
PROCEDURE
1) We will be pointing a pen light or laser pointer at the camera when all the room lights are out, the light will
be left on for different intervals (2 seconds, 5 seconds … ) .
a) The light will be moved to a different position at each interval.
b) Try to keep the light steady (no movement) unless the teacher changes your
directions.
2) Make a sketch in the rectangle of what you think the image will look like if the light is turned on for the
following intervals: 2 seconds, 5 seconds, 10 seconds - the light will be moved to a different position for each
interval.
3) You will working in teams (2), I will give each group specific directions for their light image. Make a sketch
of what you think your image will look like!
28
How dense are you?
Name:
Date:
Question: What would you rather drink – regular or diet soda?
Materials
- one unopened can of regular soda
- one unopened can of diet soda
- fish tank
- water
- scale
Procedure
1. Observe your two cans of soda. Record the volume of both cans below and record your observations.
Volume of regular soda: _____________
Volume of diet soda: ________________
Observations of cans:
2. Fill your fish tank with water to about two inches below the top of the tank.
3. Make a prediction as to what will happen when you place both soda cans into the tank of water.
Prediction:
4. Place both cans into the tank and record your observations.
Observation:
5. Why did the cans act as they did? Write your explanation below.
Explanation:
29
6. Take out both cans and dry them off completely. Find the mass of both cans and record below.
Mass of regular soda: ______________
Mass of diet soda:_____________
7. Calculate the density of each can of soda. Remember that density is equal to the mass of an object
divided by its volume. (d = m/v) Show your work!!!
Density of regular soda: _______________
Density of diet soda: ______________
8. Make changes to your explanation in step 5 now that you know the density of each can.
9. What causes the differences in the two types of soda?
10. Try this with several other types of soda and observe the differences. Which type of soda would
you choose to drink?
30
Regulation of Buoyancy
Name:
Date:
Question: Why doesn’t a fish sink?
Background Info:
If you observe a fish in an aquarium, they appear to maintain their depth effortlessly. But if you were
to put a bowling ball in a fish tank, you would not be able to keep it from sinking. At the same time, if
you put a basketball in a fish tank, you would not be able to keep it from floating. If an object is
suspended in a fluid, there is not net force on that object. The force of gravity pulling the object
towards the center of Earth is countered by an equal and opposite buoyant force (remember Newton?).
Therefore, the condition of weightlessness is also know as neutral buoyancy.
The fish in your aquarium is using this principle. Most fish have a swim bladder – a gas-filled sac located
in the upper portion of their body cavity. The gas in the bladder helps to establish neutral buoyancy by
countering the heavier tissues of the fish. By regulating the amount of gas in the bladder, fish can
regulate their buoyancy and the depth at which they remain while resting.
Materials:
- 2 liter soda bottle
- eye dropper
- permanent marker
Procedure
1. Use your permanent marker to draw a scale on your eyedropper in 5mL increments.
2. Fill your 2 liter soda bottle with water. Leave the cap off the bottle.
3. Fill about one fourth of your eyedropper with water and place it in your soda bottle. Once the
eyedropper is floating with its tip down, seal the top of your bottle and measure the amount of water in
the eyedropper. Record your measurement below.
Initial volume of eyedropper: ______________
4. Gently squeeze the sides of the soda bottle and observe what happens. Write your observation
below.
Observation:
31
5. Record the volume of the water in the eyedropper under the following conditions.
Location of the dropper
Middle of the soda bottle
Volume of water in the dropper
Bottom of the soda bottle
Eyedropper in equilibrium (no
squeezing of the bottle) from
step 3
Post-Lab questions
1. Explain why the “diver” descends when pressure is applied to the system.
2. Is more of less water displaced with the “diver” is on the bottom? Explain?
3. How might a submarine regulate its depth?
4. NASA requires astronauts in training to have experience in a weightless environment. How might
such an environment be simulated here on Earth?
32
Answer Key for Regulation of Buoyancy
1. Explain why the “diver” descends when pressure is applied to the system.
As pressure increase, the volume of air inside the eyedropper decreases (PV = nRT Ideal Gas
Law), reducing the amount of water displaced. Thus, the buoyant force is reduced while the
force of gravity remains constant, and the net downward force upon the eyedropper causes it to
sink.
2. Is more of less water displaced with the “diver” is on the bottom? Explain?
See answer for #1
3. How might a submarine regulate its depth?
Submarienes dive by allowing outside water into ballast anks. By releasing compressed air into
these ballast anks, water is forced out, causing submarines to rise because the buoyant force now
exceeds the submarine’s weight.
4. NASA requires astronauts in training to have experience in a weightless environment. How migh such
an environment be simulated here on Earth?
Using large aquariums and neutral buoyancy suits, astronauts can experience a weightless
environment on Earth.
33