Miami-Dade County Public Schools
Department of Mathematics and Science
P
roblem-based
A S S
ctivities for
ummer
Science
Grade 7
Student Exploration Guides
July 2014
chool
THE SCHOOL BOARD OF MIAMI-DADE COUNTY, FLORIDA
Ms. Perla Tabares Hantman, Chair
Dr. Lawrence S. Feldman, Vice-Chair
Dr. Dorothy Bendross-Mindingall
Ms. Susie V. Castillo
Mr. Carlos L. Curbelo
Dr. Wilbert “Tee” Holloway
Dr. Martin Karp
Dr. Marta Pérez
Ms. Raquel A. Regalado
Ms. Krisna Maddy
Student Advisor
Mr. Alberto M. Carvalho
Superintendent of Schools
Ms. Maria L. Izquierdo
Chief Academic Officer
Office of Academics and Transformation
Dr. Maria P. de Armas
Assistant Superintendent
Division of Academics
Mr. Cristian Carranza
Administrative Director
Division of Academics
Dr. Ava D. Rosales
Executive Director
Department of Mathematics and Science
Table of Contents
Student Gizmos Exploration Guides
Germination....................................................................................................................... 2
Conduction and Convection .............................................................................................. 5
Energy Conversions .......................................................................................................... 9
Radiation ........................................................................................................................... 12
Basic Prism ....................................................................................................................... 15
Density Laboratory ............................................................................................................ 18
Rock Cycle ........................................................................................................................ 22
Half Life ............................................................................................................................. 25
Natural Selection ............................................................................................................... 27
Food Chain........................................................................................................................ 31
Human Karyotyping ........................................................................................................... 35
Mouse Genetic (One Trait) ................................................................................................ 38
Building DNA ..................................................................................................................... 42
Student Exploration: Germination
Vocabulary: controlled experiment, germination, hypothesis, seed, sprout, variable
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
1. What do you think is needed for a seed grow into a sprout? This is called germination.
_________________________________________________________________________
_________________________________________________________________________
2. In the GizmoTM you can test water, light, and heat. Which factors do you think will affect
seed germination?
_________________________________________________________________________
Gizmo Warm-up: 100% Germination Challenge
How many seeds can you get to sprout? Can you get 20 out of 20 (100%)? Good luck!
1. In the Germination Gizmo, set up the three trays however you like:




Drag a packet of seeds to each tray.
Drag the Daily water slider up or down to set water level.
Click on the light bulbs to turn them on or off.
Click on the coils to set the heat level.
When you’re ready, click Play (
)!
2. After the simulation ends (five “days”), count how many sprouts you have (out of 20) in each
tray. What percent sprouted? Fill in your results in the blanks below.


To find the percent, divide your number of sprouts by 20, and then multiply by 100.
Hint for mental math: Each seed is 1/20th, or 5%, of the whole. (1/20 = .05 = 5%)
Tray 1: ____ /20 = ______%
Tray 2: ____ /20 = ______%
Tray 3: ____ /20 = ______%
3. Click Reset (
) and Clear trays. Try several more tests to see if you can get more seeds
to germinate. What conditions made the most seeds sprout?
Seed type: _____
Daily water: _____ mL
M-DCPS Grade 7 Science Credit Recovery
Heat: __________
% sprouted = ______ %
Page 2 of 45
Get the Gizmo ready:
Activity A:


Water and
germination
Click Reset.
Click Clear pots.
Question: Do seeds need water to germinate?
1. Form a hypothesis: Do seeds need water to germinate? Circle what you think below. This is
your hypothesis.
No, plants need no water.
Yes, plants need some water.
Yes, plants need lots of water.
2. Set up Gizmo: Now you will set up a fair test. A test is fair when all conditions are kept the
same except the one(s) you are testing. In science this is called a controlled experiment.
The condition that changes (or varies) is the variable being tested. Set up the trays like this:

Tray 1: seed A, 0 mL water per day, all 3 lights on, heat low

Tray 2: seed A, 50 mL water per day, all 3 lights on, heat low

Tray 3: seed A, 100 mL water per day, all 3 lights on, heat low
3. Experiment: Time to test your hypothesis. Click Play to start. When the Gizmo stops, count
the number of sprouts in each tray. Record your data below.
Tray
Seed
Amount of
water
Amount of
light
Amount of
heat
Number of sprouts
1
A
0 mL per day
3 lights on
low
_____ /20 = _____ %
2
A
50 mL per day
3 lights on
low
_____ /20 = _____ %
3
A
100 mL per day
3 lights on
low
_____ /20 = _____ %
4. Revise and repeat: What is the ideal amount of water for germination of Seed A? What is
ideal for Seeds B and C? Write your findings below.
Seed A: ______ mL per day
Seed B: ______ mL per day
Seed C: ______ mL per day
5. Draw conclusions: In general, do seeds need water to germinate? Explain.
_________________________________________________________________________
_________________________________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 3 of 45
Get the Gizmo ready:
Activity B:


Lighten up!
Click Reset.
Click Clear pots.
Question: Do seeds need light to germinate?
1. Form a hypothesis: Do seeds need light to germinate? Circle your hypothesis.
All seeds need light.
Some seeds need light.
No seeds need light.
2. Set up Gizmo: In the Gizmo, design a controlled experiment using Seed A. Remember that
a controlled experiment keeps everything the same except what is being tested. Fill in the
settings you will use in the table below. (Leave the number of sprouts blank for now.)
Amount of
water
Amount of
light
Amount of
heat
Tray
Seed
Number of sprouts
1
A
_____ /20 = _____ %
2
A
_____ /20 = _____ %
3
A
_____ /20 = _____ %
3. Experiment: Click Play to run your experiment. Record your results in the table above.
4. Analyze: Does seed A need light to germinate? How do you know this?
_________________________________________________________________________
5. Revise and repeat: Run a similar experiment with seeds B and C. Do seeds B and C need
light to germinate? Describe your findings.
_________________________________________________________________________
_________________________________________________________________________
6. Draw conclusions: In general, do seeds need light to germinate? Explain.
_________________________________________________________________________
_________________________________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 4 of 45
Student Exploration: Conduction and Convection
Vocabulary: conduction, conductor, convection, insulator
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
1. Two pots have been sitting on the stove for a while. One pot has a copper handle and the
other has a wooden handle. Which handle would you rather touch? Why?
_________________________________________________________________________
_________________________________________________________________________
2. One of the pots is filled with soup. The soup at the bottom of the pot is warmed by the stove
burner, but how does the soup at the top get hot?
_________________________________________________________________________
_________________________________________________________________________
Gizmo Warm-up
The Conduction and Convection Gizmo™ shows two flasks
of colored water, one blue and one yellow. Select Copper
and Solid chunk from the dropdown lists. (This means the
two flasks are separated by a solid piece of copper, and the
two liquids cannot touch each other.)
1. Use the sliders to make one flask hotter than the other.
Click Play (
). What happens? __________________
_____________________________________________
2. Select the Data tab and look at the graph. What do the blue curve and the yellow curve
represent?
A. The blue curve represents ______________________________________________
B. The yellow curve represents ____________________________________________
3. What is the final temperature of the top flask? ____________ Bottom flask? ____________
M-DCPS Grade 7 Science Credit Recovery
Page 5 of 45
Get the Gizmo ready:
Activity A:
Conduction
 Click Reset (
).
 Set the Initial temperature of the top flask to 95°C
and the bottom flask to 5°C.
Question: Conduction is the transfer of heat from one object to another by direct contact.
Which materials conduct heat most easily?
1. Observe: Run the Gizmo twice – once with a Solid chunk of Copper separating the liquids,
and once with a Solid chunk of Stone. Watch how quickly the temperatures of the liquids
change in both cases. (Note: This solid chunk keeps the liquids from mixing.)
2. Form hypothesis: A conductor allows heat to flow easily, while an insulator resists heat
flow. In general, what kinds of materials do you think are good conductors?
_________________________________________________________________________
3. Predict: Of the six substances in the Gizmo, which ones will allow the fastest temperature
change in the two flasks? ____________________________________________________
4. Experiment: Experiment with all six Solid chunks. For each, click Fast forward (
) and
then, after about 500 seconds, Pause (
). Record the temperature of each flask.
Connection
Initial temp.
(top flask)
Initial temp.
(bottom flask)
Solid copper
95°C
5°C
Solid gold
95°C
5°C
Solid lead
95°C
5°C
Solid stone
95°C
5°C
Solid glass
95°C
5°C
Solid rubber
95°C
5°C
500 sec. temp.
(top flask)
500 sec. temp.
(bottom flask)
5. Analyze: What substances conducted heat the best? _______________________________
How do you know? _________________________________________________________
6. Draw conclusions: What do the best conductors have in common? ____________________
_________________________________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 6 of 45
Get the Gizmo ready:
Activity B:
Convection
 Click Reset.
 Select Glass and Hollow pipe in the dropdowns.
Question: Convection is the transfer of heat by the movement of matter. In what
situations does convection work best?
1. Observe: The Hollow pipe allows the water in each flask to move around and mix. Try
several experiments with different temperatures in the top and bottom flasks.
A. Describe what you see: ________________________________________________
___________________________________________________________________
B. How does the color show when convection (movement of hot water) is taking place?
___________________________________________________________________
2. Form hypothesis: Why do you think the water mixes quickly in some cases, while other
times the water mixes slowly? _________________________________________________
_________________________________________________________________________
3. Experiment: Predict the results of each experiment by writing “fast” or “slow” in the
predictions column. Test your predictions on the Gizmo, and record the actual results.
Initial temperature
(top flask)
Initial temperature
(bottom flask)
95°C
5°C
5°C
95°C
Mixing speed
(predictions)
Mixing speed
(actual results)
4. Analyze: How do the positions of the hot and cold water affect the speed of convection?
_________________________________________________________________________
_________________________________________________________________________
5. Draw conclusions: Does hot water tend to rise or sink? Explain. ______________________
_________________________________________________________________________
_________________________________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 7 of 45
Activity C:
Conduction vs.
convection
Get the Gizmo ready:
 Set the Initial temperatures of the top flask to
30°C and the bottom flask to 70°C.
 Select Gold from the dropdown list.
Question: Which works more quickly, conduction or convection?
1. Observe: Experiment with a Hollow pipe of Gold and a Solid chunk of Gold separating the
flasks. Compare how quickly heat is exchanged.
2. Form hypothesis: Heat can be transferred by conduction or convection.
A. Which process do you think is quicker? ____________________________________
B. Why do you think this is so? ____________________________________________
___________________________________________________________________
3. Experiment: For each of the situations below, record the temperatures after 100 seconds.
Connection
Initial temp.
(top flask)
Initial temp.
(bottom flask)
Solid gold
30°C
70°C
Hollow gold
30°C
70°C
Solid gold
70°C
30°C
Hollow gold
70°C
30°C
100 sec. temp.
(top flask)
100 sec. temp.
(bottom flask)
4. Draw conclusions: Does convection always work more quickly than conduction? Explain
why or why not. ____________________________________________________________
_________________________________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 8 of 45
Student Exploration: Energy Conversions
Vocabulary: chemical energy, electrical current, energy, fossil fuel, global warming,
gravitational potential energy, hydroelectricity, kinetic energy, light, nonrenewable resource,
nuclear energy, renewable resource, sound, thermal energy
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
1. What are sources of electricity? List as many as you can. ___________________________
_________________________________________________________________________
_________________________________________________________________________
2. Where do people and other animals get energy to move around? _____________________
_________________________________________________________________________
3.
Where do plants get energy to live and grow? ____________________________________
_________________________________________________________________________
Gizmo Warm-up
In the Energy Conversions Gizmo™, be sure Information
mode is selected. Click on each of the different items in the
scene and read about each one.
1. Which object converts sunlight into sugars?
__________________________________________
2. Which object converts wind power to electricity?
__________________________________________
3. Which object converts light to electricity? ________________________________________
4. Which object converts electricity to light? ________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 9 of 45
Activity A:
Energy Paths
Get the Gizmo ready:
 Select the Path mode.
Question: Where do we get energy to run, climb, play, and do all the other things we do?
1. Form hypothesis: Where do you think we humans get energy? _______________________
_________________________________________________________________________
2. Create a path: You will now form an energy path to see where our energy comes from.
i. Click on the person and read. Where do people get energy? __________________
ii. Now click on the chicken. Where does the chicken get energy? ________________
iii. Click on the corn. Where does the corn get energy? _________________________
iv. Click on the Sun. How does the Sun get energy? ____________________________
___________________________________________________________________
v. Fill in the energy path below starting with the Sun.
______________
______________
______________
______________
3. Apply: Click Reset and then click on the toaster. Using the Gizmo, create four energy paths
to explain how the toaster could get its energy. (One path will only have three objects.)
i. ______________
______________
______________
______________
ii. ______________
______________
______________
______________
iii. ______________
______________
______________
______________
iv. ______________
______________
______________
______________
4. Analyze: Where does each path begin? _________________________________________
5. Draw conclusions: What would life on Earth be like without the Sun? __________________
_________________________________________________________________________
_________________________________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 10 of 45
M-DCPS Grade 7 Science Credit Recovery
Page 11 of 45
Get the Gizmo ready:
Activity B:
 Click Reset.
 Check that Path mode is still selected.
Energy
Conversions
Question: How is energy changed from one form to another?
1. Classify: Energy is the ability to exert force and cause change. Energy has many forms:

Kinetic energy is energy of motion. All moving things have kinetic energy.
o
Sound is energy of vibrating materials or air molecules.
o
Thermal energy is the energy of tiny moving particles. As an object heats up,
particles move faster and thermal energy increases.

Gravitational potential energy is stored energy that exists based on the position of
an object. The higher an object is, the greater its gravitational potential energy.

Electrical current is energy that comes from moving charged particles.

Light is electromagnetic waves that are visible to the eye.

Chemical energy is energy that is stored in the bonds holding atoms together.

Nuclear energy is energy released when atoms split apart or join together.
2. Create path: Create an energy path in the Gizmo, starting at the Sun. For each step of the
path, describe the energy conversion that takes place. The first one is done for you. Discuss
your answers with your classmates and teacher.
Energy Path
Energy conversion
____Sun_____
Nuclear energy is converted to light and thermal energy.
____________
____________
____________
3. On your own: Create at least two more paths on the Gizmo. List the energy conversions that
happen along each path. Record your work on separate paper or in your notebook.
M-DCPS Grade 7 Science Credit Recovery
Page 12 of 45
Student Exploration: Radiation
Vocabulary: filament, infrared, Kelvin scale, radiation
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
1. The Sun is millions of kilometers away. How can heat from the Sun get here? ___________
_________________________________________________________________________
2. If you look inside an electric stove or toaster oven, how can you tell whether it’s turned on?
_________________________________________________________________________
Gizmo Warm-up
In the Radiation Gizmo™, you can focus the light of a superpowerful flashlight upon a kernel of popcorn and see what happens.
The lens, which focuses the light, can be moved to the left or right.
1. The Temperature slider controls the heat of the metal filament
inside the light. Scientists use the Kelvin scale to measure the
temperature of very hot objects. It is like the Celsius scale
except 0 K (absolute zero) is the coldest anything can ever be.
Slowly move the Temperature slider all the way to the right. What happens? ____________
_________________________________________________________________________
The light energy emitted by the flashlight is called radiation.
2. Slide the lens so the distance to the flashlight is 40 cm. Press Play (
). What happens?
_________________________________________________________________________
3. Do you think the kernel will pop if you place cardboard in front of the flashlight? __________
4. Click Reset (
). At the top of the Gizmo, next to Obstacle, select Cardboard. Press
Play. What happens? _______________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 13 of 45
Get the Gizmo ready:
Activity A:
What does the
popping?




Click Reset.
Set Temperature to 1500 K.
Slide the lens so it is 50 cm from the light.
For Obstacle, select None.
Question: How does heat get from the flashlight’s metal filament to the kernel?
1. Observe: Press Play. How long does it take the kernel to pop? _______________________
2. Form hypothesis: Inside the light bulb is a very hot piece of metal, called the filament. It
gives off light because it is so hot. In addition, the glass bulb gets hot and heats the air.
How do you think heat gets from the filament to the kernel? __________________________
_________________________________________________________________________
_________________________________________________________________________
3. Predict: Click Reset and select Cardboard. This blocks all light and some of the hot air.
Based on your hypothesis, how will this affect popping time? Explain. __________________
_________________________________________________________________________
4. Test: Click Play or Fast forward (
). Was your prediction correct? __________________
5. Predict: Click Reset and select Red glass. This lets most of the light through but still blocks
some air. What do you think will happen? Explain. _________________________________
_________________________________________________________________________
6. Test: Click Play or Fast forward. What did you find? _______________________________
7. Draw conclusions: When the popcorn kernel popped, was it because it was heated by light
(radiation) or hot air from the flashlight? Explain how you know this.
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 14 of 45
Get the Gizmo ready:
Activity B:
Out of sight



Click Reset.
Slide the lens so it is 60 cm from the light.
Set the Temperature to 2000 K.
Goal: Understand that light is both visible and invisible.
1. Observe: Select Blue glass. How does this affect the light that gets to the corn? _________
_________________________________________________________________________
2. Conjecture: Will the corn pop when you start the simulation? Explain. __________________
_________________________________________________________________________
3. Experiment: Click Fast forward. What happens? _________________________________
4. Draw conclusions: The filament radiates both visible light (orange in this case) and invisible
light (infrared light). Did the blue glass block infrared light? Explain how you can tell.
_________________________________________________________________________
_________________________________________________________________________
5. Run Gizmo: Click Reset. Remove the glass. Click Play. When does the corn pop? _______
6. Analyze: Compare the popping times with and without the blue glass. Is most of the
radiation given off by the filament red or infrared? Explain. ___________________________
_________________________________________________________________________
7. Test: Click Reset. Select Cardboard and then click Fast forward. Does the cardboard block
infrared light? Explain. _______________________________________________________
_________________________________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 15 of 45
Student Exploration: Basic Prism
Vocabulary: angle of incidence, angle of refraction, critical angle, dispersion, index of
refraction, medium, prism, refract, Snell’s law, total internal reflection, visible spectrum,
wavelength
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
A prism is a transparent object that can be used to bend, or refract, light. The photo below
shows what happens when sunlight passes through a prism.
1. What do you see? ________________________________
_______________________________________________
2. What does this indicate about the composition of sunlight?
_______________________________________________
_______________________________________________
Gizmo Warm-up
The Basic Prism Gizmo™ allows you to investigate how
a prism refracts light. The Gizmo shows a laser emitting
a beam of light through a triangular prism.
To begin, check that Single color beam is selected, λ
is 500 nm, n is 1.50, w is 2.0, and the angle (θ) is 0°.
1. What do you notice about the path of light when it passes through the prism? ___________
_________________________________________________________________________
2. Move the λ slider to increase and then to decrease the wavelength of the beam of light.
A. How does this affect the color of the light ray? ______________________________
___________________________________________________________________
B. How does this affect the direction of the light ray? ___________________________
___________________________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 16 of 45
Get the Gizmo ready:
Activity A:
Refraction and
dispersion
 Set λ to 500 nm and n to 1.00.
 Check that w is 2.0 and θ is 0°.
Introduction: When light passes from a vacuum into a medium such as glass, it slows down.
The index of refraction (n) is equal to the ratio of the speed of light in a vacuum to the speed of
light in a medium. The index of refraction of air is very close to 1.00.
Question: What factors affect the refraction of light through a prism?
1. Observe: What do you notice about the beam of light when the n is 1.00? ______________
_________________________________________________________________________
2. Predict: How do you think increasing the index of refraction will change the path of the light?
_________________________________________________________________________
3. Observe: Slowly increase n to 1.50, close to the value for glass. What happens? ________
_________________________________________________________________________
4. Observe: Increase n to 1.53. What happens now? _________________________________
_________________________________________________________________________
In this situation, the light cannot move from the prism into the air. Instead, it reflects off the
surface, a phenomenon called total internal reflection.
5. Gather data: Set n to 1.50. The Gizmo also allows you to change the width of the prism (w),
the angle of the prism (θ), and the wavelength of the light (λ). Describe the effect of each
action listed below. Return the Gizmo to its starting conditions after each trial.
Action
Effect on path of light ray exiting the prism
Decrease w to 1.0.
Increase w to 3.0.
Decrease θ to -30°.
Increase θ to 30°.
Decrease λ to 400 nm.
Increase λ to 700 nm.
(Activity A continued on next page)
M-DCPS Grade 7 Science Credit Recovery
Page 17 of 45
Activity A (continued from previous page)
6. Summarize: Which actions caused the amount of refraction to increase? _______________
_________________________________________________________________________
Which actions caused the amount of refraction to decrease? _________________________
_________________________________________________________________________
7. Think and discuss: Why does widening the prism cause the beam to bend more? If possible,
discuss your answer with your classmates and teacher.
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
8. Observe: Return the Gizmo to its initial settings (n = 1.50, w = 2.0, θ = 0°). Select White
light from the menu at upper left. What happens when white light goes through a prism?
_________________________________________________________________________
_________________________________________________________________________
The band of colors you see is called a visible spectrum. The ability of a prism to separate
white light into a spectrum is called dispersion. (Note: The Gizmo shows the spectrum as a
collection of individual colored beams rather than a continuous band of color that would be
produced by a real prism.)
M-DCPS Grade 7 Science Credit Recovery
Page 18 of 45
Student Exploration: Density Laboratory
Vocabulary: buoyancy, density, graduated cylinder, mass, matter, scale, volume
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
1. Of the objects below, circle the ones you think would float in water.
2. Why do some objects float, while others sink? ____________________________________
_________________________________________________________________________
_________________________________________________________________________
Gizmo Warm-up
The Density Laboratory Gizmo™ allows you to measure a variety of
objects, then drop them in water (or other liquid) to see if they sink or float.
1. An object’s mass is the amount of matter it contains. The mass of an
object can be measured with a calibrated scale like the one shown in
the Gizmo. Drag the first object onto the Scale. (This is object 1.)
What is the mass of object 1? _______________________________
2. An object’s volume is the amount of space it takes up. The volume of
an irregular object can be measured by how much water it displaces in
a graduated cylinder. Place object 1 into the Graduated Cylinder.
What is the volume of object 1? _____________________________
Note: While milliliters (mL) are used to measure liquid volumes, the equivalent unit cubic
centimeters (cm3) are used for solids. Therefore, write the volume of object 1 in cm3.
3. Drag object 1 into the Beaker of Liquid. Does it sink or float? ________________________
M-DCPS Grade 7 Science Credit Recovery
Page 19 of 45
Activity A:
Float or sink?
Get the Gizmo ready:
 Drag object 1 back to the shelf.
 Check that Liquid Density is set to 1.0 g/mL.
Question: How can you predict whether an object will float or sink?
1. Observe: Experiment with the different objects in the Gizmo. Try to determine what the
floating objects have in common and what the sinking objects have in common.
2. Form hypothesis: Compare the floating objects, then do the same for the sinking objects.
i. What do the floating objects have in common? ______________________________
___________________________________________________________________
ii. What do the sinking objects have in common? ______________________________
___________________________________________________________________
3. Collect data: Measure the mass and volume of objects 1 through 12, and record whether
they float or sink in the table below. Leave the last column blank for now.
Object
Mass (g)
Volume (cm3)
Float or sink?
1
2
3
4
5
6
7
8
9
10
11
12
(Activity A continued on next page)
M-DCPS Grade 7 Science Credit Recovery
Page 20 of 45
Activity A (continued from previous page)
4. Analyze: Look carefully for patterns in your data.
i. Does mass alone determine whether an object will float or sink? ________________
Explain: ____________________________________________________________
ii. Does volume alone determine whether an object will float or sink? ______________
Explain: ____________________________________________________________
iii. Compare the mass and volume of each object. What is true of the mass and volume
of all the floating objects? ______________________________________________
iv. What is true of the mass and volume of all the sinking objects? _________________
___________________________________________________________________
5. Calculate: The density of an object is its mass per unit of volume. Dense objects feel very
heavy for their size, while objects with low density feel very light for their size.
To calculate an object’s density, divide its mass by its volume. If mass is measured in grams
and volume in cubic centimeters, the unit of density is grams per cubic centimeter (g/cm 3).
Calculate the density of each object, and record the answers in the last column of your data
table. Label this column “Density (g/cm3).”
6. Analyze: Compare the density of each object to the density of the liquid, 1.0 g/mL. This is
the density of water.
i. What do you notice about the density of the floating objects? ___________________
___________________________________________________________________
ii. What do you notice about the density of the sinking objects? ___________________
___________________________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 21 of 45
Get the Gizmo ready:
Activity B:
Liquid density
 Drag all the objects back onto the shelf.
 Check that the Liquid Density is still 1.0 g/mL.
Question: How does liquid density affect whether objects float or sink?
1. Observe: Place object 1 into the Beaker of Liquid. Slowly move the Liquid Density slider
back and forth. What do you notice? __________________________________________
________________________________________________________________________
2. Form a hypothesis: Buoyancy is the tendency to float. How do you think the liquid density
affects the buoyancy of objects placed in the liquid? _______________________________
_________________________________________________________________________
3. Predict: In the table below, write the density of each object. Then predict whether the object
will float or sink in each of the fluids. Write “Float” or “Sink” in each empty box of the table.
Object
Object density
Liquid density
0.5 g/mL
1.0 g/mL
2.0 g/mL
1
2
3
4
5
4. Test: Test your predictions using the Gizmo. Place a checkmark (\/) next to each correct
prediction, and an “X” next to each incorrect prediction.
5. Draw conclusions: What is the relationship between the object density, the liquid density,
and the tendency of the object to float? __________________________________________
_________________________________________________________________________
_________________________________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 22 of 45
_________________________________________________________________________
Student Exploration: Rock Cycle
Vocabulary: deposition, erosion, extrusive igneous rock, intrusive igneous rock, lava,
lithification, magma, metamorphic rock, rock cycle, sediment, sedimentary rock, soil, weathering
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
1. What happens to hot lava after it erupts from a volcano? _________________________
_________________________________________________________________________
2. How does rock turn into soil? _________________________________________________
_________________________________________________________________________
3. The Mississippi River carries tons of tiny rock fragments called sediments into the Gulf of
Mexico. What do you think will happen to these sediments after a few million years?
_________________________________________________________________________
_________________________________________________________________________
Gizmo Warm-up
Over millions of years, rocks are broken down
and transformed into other rocks. The Rock Cycle
Gizmo™ illustrates the different transformations
that make up the rock cycle. Before exploring
the Gizmo, take a look at the image.
1. What types of rocks are shown? __________
____________________________________
____________________________________
2. Magma is molten (liquid) rock under Earth’s surface. Based on the image, how do you think
magma turns into extrusive igneous rock? ______________________________________
3. Click Extrusive igneous rock button to the right of the image. Were you correct? ________
M-DCPS Grade 7 Science Credit Recovery
Page 23 of 45
Get the Gizmo ready:
Activity:
The rock cycle
 Click Start again.
Question: What is the rock cycle?
1. Observe: A cycle is a path with the same start and end. Create a rock cycle with the Gizmo.
i. Click Magma. How hot is magma? _______________________________________
ii. Click Crystallization (below ground). What kind of rock is formed when magma
cools below the surface? _______________________________________________
iii. Click Exposure and weathering. What forms when rocks break down? __________
iv. Click Erosion and deposition. In what ways are sediments transported? _________
___________________________________________________________________
v. Click Lithification and compaction. (Lithification is hardening into rock.) What
kind of rock is formed from sediments? ____________________________________
vi. Click Increase temp. and pressure. What kind of rock is formed? ______________
vii. Click Melt. What is formed when rocks melt deep underground? ________________
2. Describe: Select the PATH tab. What are the steps in this rock cycle? _________________
_________________________________________________________________________
3. On your own: On the SIMULATION tab, click Start again. In the spaces below, list three
rock cycles. You can start anywhere, but each cycle must begin and end at the same point.
Cycle 1: __________________________________________________________________
_________________________________________________________________________
Cycle 2: __________________________________________________________________
_________________________________________________________________________
Cycle 3: __________________________________________________________________
_________________________________________________________________________
(Activity continued on next page)
M-DCPS Grade 7 Science Credit Recovery
Page 24 of 45
Activity (continued from previous page)
4. Diagram: The image below summarizes the different stations in the rock cycle. Draw an
arrow to represent each possible transition from one rock type to another. Then label each
arrow with the process that occurs, such as “weathering” or “erosion and deposition.”
5. Practice: List the steps that would cause each transformation below.
i. Intrusive igneous rock  sedimentary rock: _____________________________
___________________________________________________________________
ii. Metamorphic rock  sediment: _________________________________________
___________________________________________________________________
iii. Sediment  sedimentary rock: __________________________________________
___________________________________________________________________
iv. Sedimentary rock  sediment: __________________________________________
___________________________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 25 of 45
Student Exploration: Half-life
Get the Gizmo ready:
Activity B:
Measuring half-life
 Click Reset.
 Select Isotope A from the left drop-down menu.
 Check that Theoretical decay is selected.
Introduction: Different isotopes of the same element have the same number of protons but
different numbers of neutrons in the nucleus. Some isotopes are radioactive.
Question: How do we find the half-life of a radioactive isotope?
1. Observe: Select the GRAPH tab, and click Play. Based on the graph, what is your estimate
of the half-life of isotope A? ________________________
2. Measure: Turn on the Half-life probe. Use the probe to measure how long it takes for
exactly one-half of the original radioactive atoms to decay.
What is the exact half-life of isotope A? ________________________
3. Collect data: In the first row of the table below, write how many seconds represent one halflife, two half-lives, and so forth. On the next row, predict the number of radioactive atoms
that will be present at each time. Then use the probe to find the actual values.
Half-life
0
1
2
3
4
5
Time (seconds)
Predicted #
radioactive atoms
Actual #
radioactive atoms
4. Calculate: Calculate the percentage of radioactive atoms that are left after each half-life.
Half-life
0
1
2
3
4
5
Percentage
radioactive atoms
5. Apply: Suppose you found a material in which 12.5% of the original radioactive atoms were
present. If the half-life is 47 years, how old is the material? __________________________
M-DCPS Grade 7 Science Credit Recovery
Page 26 of 45
6. Apply: Use the Gizmo to find the half-life of Isotope B. What is it? ____________________
7. Practice: Click Reset. Select the Mystery half-life from the left menu. In this setting, the
half-life will be different each time you run the simulation. Run at least three trials. In each
trial, measure the half-life using the Half-life probe on the graph.
When you have found the half-life, click the camera icon ( ) to take a snapshot of the
graph and probe. Paste the images into a blank document, and label each image with the
half-life. Print out this document and turn it in with this sheet.
8. Explore: Use the Gizmo to explore whether the number of atoms present affects the half-life
that you measure. Describe your findings below:
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
9. Extend your thinking: The slow decay of radioactive materials can be used to find the age of
rocks, fossils, and archaeological artifacts. In a process called radiometric dating,
scientists measure the proportions of radioactive atoms and daughter atoms in an object to
determine its age. Carbon-14 is a useful isotope because it is found in wood, ash, bone, and
any other organic materials.
You can use the Half-life Gizmo to model the decay of Carbon-14, which has a half-life of
approximately 6,000 years (actual value is 5,730 years). In the Gizmo, select User chooses
half-life and Theoretical decay. Set the Half-life to 6 seconds (to represent 6,000 years)
and the Number of atoms to 100.
Use the Gizmo to estimate the age of each of the objects below. For these questions, each
second in the Gizmo represents 1,000 years.
Description
Age (years)
Egyptian papyrus with 63% of its original carbon-14 atoms
Aboriginal charcoal with 22% of its original carbon-14 atoms.
Mayan headdress with 79% of its original carbon-14 atoms
Neanderthal skull with 3% of its original carbon-14 atoms
M-DCPS Grade 7 Science Credit Recovery
Page 27 of 45
Student Exploration: Natural Selection
Vocabulary: biological evolution, camouflage, Industrial Revolution, lichen, morph, natural
selection, peppered moth
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
The peppered moth (Biston betularia) is a common moth
found in Europe, Asia, and North America. It is commonly
found in two forms, or morphs: a dark morph and a light,
speckled morph. Birds are a frequent predator of the
peppered moth.
1. Which morph do you think would be easier to see on a
dark tree trunk? _______________________________
2. Which morph do you think would be easier to see on a
light tree trunk? _______________________________
Gizmo Warm-up
The Natural Selection Gizmo™ allows you to play the role of
a bird feeding on peppered moths. The initial population of
40 moths is scattered over 20 tree trunks. Click on moths to
capture them. Click the Next tree button or hit the spacebar
on your keyboard to advance to the next tree.
1. Check that LIGHT TREES is selected. Click Start and
hunt moths for one year.
A. How many dark moths did you capture? _______
B. How many light moths did you capture? _______
How many moths can you find?
C. Camouflage is coloring or patterns that help an organism to blend in with the
background. Which type of moth is better camouflaged on light bark? ____________
2. If a forest contained mostly light-colored trees, which type of moth would you expect to be
most common? ____________________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 28 of 45
Get the Gizmo ready:
Activity A:
 Click Reset.
 Check that the LIGHT TREES tab is selected.
Light trees
Introduction: Before the 19th century in England, the air was very clean. The bark on trees was
usually light in color. Abundant lichens growing on tree trunks also lightened their appearance.
Question: How does the color of a peppered moth affect survival?
1. Predict: Over time, what will to happen to the populations of light and dark moths on light
trees? ____________________________________________________________________
2. Experiment: Click Start and hunt peppered moths on light tree trunks for five years. In each
year, try to capture as many moths as you can. (Hint: Use the spacebar on your keyboard
to advance to the next tree.)
After 5 years, select the TABLE tab and record the percentages of each moth type. (Note:
The table shows current populations of each moth, not the number of captured moths.)
Year
Dark moths
Light moths
0
1
2
3
4
5
3. Analyze: What do your results show? ___________________________________________
_________________________________________________________________________
4. Apply: Which type of moth do you think was more common before the 19th century, when
most trees were light in color? _________________________________________________
5. Extend your thinking: What strategies did you use to hunt for moths? __________________
_________________________________________________________________________
_________________________________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 29 of 45
Get the Gizmo ready:
Activity B:
 Click Reset.
 Select the DARK TREES tab.
Dark trees
Introduction: The 19th century was the time of the Industrial Revolution in England. Most of
the new industries used coal for energy, and the air was polluted with black soot. In forests near
factories, the soot coated trees and killed lichens. As a result, tree trunks became darker.
Question: How did air pollution affect moth populations?
1. Predict: Over time, what will to happen to the populations of light and dark moths on dark
trees? ____________________________________________________________________
2. Experiment: Click Start and hunt peppered moths on dark tree trunks for five years. In each
year, try to capture as many moths as you can. (Hint: You can use the spacebar on your
keyboard to advance to the next tree.)
When you are done, select the TABLE tab and record the percentages of each moth type.
Year
Dark moths
Light moths
0
1
2
3
4
5
3. Analyze: What do your results show? ___________________________________________
_________________________________________________________________________
4. Apply: Which type of moth do you think was more common during the 19th century? Why?
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
(Activity B continued on next page)
M-DCPS Grade 7 Science Credit Recovery
Page 30 of 45
Activity B (continued from previous page)
5. Draw conclusions: Natural selection is the process by which favorable traits tend to
increase in frequency over time. How does this experiment illustrate natural selection?
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
6. Think and discuss: Did the changes you observed in the moth populations result from
individual moths changing colors? Or did they occur because the best-hidden moths
survived and reproduced, passing on their colors to their offspring? Explain your answer.
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 31 of 45
Student Exploration: Food Chain
Vocabulary: consumer, ecosystem, equilibrium, food chain, population, predator, prey,
producer
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
The Food Chain Gizmo™ shows a food chain with hawks, snakes, rabbits, and grass. In this
simulation, the hawks eat snakes, the snakes eat rabbits, and the rabbits eat grass.
1. Producers are organisms that do not need to eat other organisms to obtain energy.
a. Which organism is a producer in this food chain? ____________________________
b. Where does the producer get its energy? __________________________________
2. Consumers must eat other organisms for energy. Which organisms are consumers in this
food chain? _______________________________________________________________
Gizmo Warm-up
The SIMULATION pane of the Gizmo shows the current population,
or number, of each organism in the food chain.
1. What are the current populations of each organism?
Hawks: _____ Snakes: _____ Rabbits: _____ Grass: _____
2. Select the BAR CHART tab, and click Play (
). What do you
notice about each population as time goes by?
_________________________________________________________________________
If populations don’t change very much over time, the ecosystem is in equilibrium.
3. Compare the equilibrium populations of the four organisms. Why do you think populations
decrease at higher levels of the food chain? ______________________________________
_________________________________________________________________________
_________________________________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 32 of 45
Activity A:
Get the Gizmo ready:
 Click Reset (
).
 Check that the BAR CHART tab is selected.
Predator-prey
relationships
Question: Predators are animals that hunt other animals, called prey. How do predator
and prey populations affect one another?
1. Observe: Run the Gizmo with several different starting conditions. You can use the + or –
buttons to add or remove organisms, or you can choose Diseased from the dropdown lists.
2. Form hypothesis: How do you think predator and prey populations affect one another?
_________________________________________________________________________
_________________________________________________________________________
3. Predict: Based on your hypothesis, predict how changing the rabbit population will affect the
other organisms at first. Write “Increase” or “Decrease” next to each “Prediction” in the table.
Change
Grass
Snakes
Hawks
Doubling
rabbit
population
Prediction:
Prediction:
Prediction:
Result:
Result:
Result:
Halving
rabbit
population
Prediction:
Prediction:
Prediction:
Result:
Result:
Result:
4. Test: Add rabbits until the population is about twice as large as it was (200% of balance).
Click Play, and then Pause (
) after approximately ONE month. Next to each “Result”
line in the table, write “Increase” or “Decrease.” Click Reset and then halve the rabbit
population (50% of balance). Record the results for this experiment in the table as well.
i. How did doubling the rabbit population affect the grass, snakes, and hawks at first?
___________________________________________________________________
___________________________________________________________________
ii. How did halving the rabbit population affect the grass, snakes, and hawks at first?
___________________________________________________________________
___________________________________________________________________
(Activity A continued on next page)
M-DCPS Grade 7 Science Credit Recovery
Page 33 of 45
Activity A (continued from previous page)
5. Predict: Predict how changing the snake and hawk populations will affect the other
organisms within the first month. In the tables below, write your predictions.
Change
Grass
Rabbits
Hawks
Doubling
snake
population
Prediction:
Prediction:
Prediction:
Result:
Result:
Result:
Halving
snake
population
Prediction:
Prediction:
Prediction:
Result:
Result:
Result:
Change
Grass
Rabbits
Snakes
Doubling
hawk
population
Prediction:
Prediction:
Prediction:
Result:
Result:
Result:
Halving
hawk
population
Prediction:
Prediction:
Prediction:
Result:
Result:
Result:
6. Test: Click Reset. Try each experiment with the Gizmo. Record each result after one month.
i. How did increasing the snakes affect the grass? ____________________________
Explain why: ________________________________________________________
___________________________________________________________________
ii. How did increasing the hawks affect the rabbits? ____________________________
Explain why: ________________________________________________________
___________________________________________________________________
7. Draw conclusions: In general, what effect did removing prey have on predators? _________
_________________________________________________________________________
What effect did removing predators have on prey? _________________________________
_________________________________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 34 of 45
Activity B:
Long-term
changes
Get the Gizmo ready:
 Click Reset.
 Select the GRAPH tab.
Question: An ecosystem is a group of living things and their physical environment. How
do ecosystems react to major disturbances?
1. Observe: Kill off most of the hawks using the – button, and then click Play. Observe the
GRAPH for about 12 months, and then click Pause. What happens?
_________________________________________________________________________
_________________________________________________________________________
2. Analyze: Explain why you think the population of each organism changed the way it did.
(Use extra paper if necessary.)
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
3. Experiment: Click Reset. Try making other changes to the ecosystem. Use the + or –
buttons, or choose Diseased from the dropdown lists. Click Play and observe for at least 12
months. Record what happens on another sheet of paper or in your notes.
4. Summarize: Give at least one example of each of the following:
i. A major disturbance that the ecosystem was able to recover completely from.
___________________________________________________________________
ii. A major disturbance that caused the ecosystem to stabilize at a new equilibrium.
___________________________________________________________________
iii. A major disturbance that caused the ecosystem to completely collapse.
___________________________________________________________________
iv. (Challenge) A major disturbance that almost caused a total collapse, but that the
ecosystem was able to recover from eventually.
___________________________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 35 of 45
Student Exploration: Human Karyotyping
Vocabulary: autosome, chromosomal disorder, chromosome, genome, karyotype, sex
chromosome
Prior Knowledge Question (Do this BEFORE using the Gizmo.)
A chromosome is a rod-shaped structure made of coils of DNA. Most human cells have 23
pairs of chromosomes.
1. Why do you think humans have two sets of 23 chromosomes? (Hint: Where did each set
come from?) ______________________________________________________________
_________________________________________________________________________
2. How do you think different people’s chromosomes would compare? ___________________
_________________________________________________________________________
Gizmo Warm-up
Scientists use karyotypes to study the chromosomes in a cell. A
karyotype is a picture showing a cell’s chromosomes grouped
together in pairs.
In the Human Karyotyping Gizmo™, you will make karyotypes
for five individuals. Take a look at the SIMULATION pane. Use
the arrows to click through the numbered list of chromosomes at
the bottom right of the pane.
1. How does the appearance of the chromosomes change as
you move through the list? __________________________
________________________________________________
_________________________________________________
2. Examine the chromosomes labeled x and y. How do these two chromosomes compare?
______________________________________________________________________
______________________________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 36 of 45
Activity A:
Get the Gizmo ready:
Male and female
 Click Reset.
karyotypes
Question: How are male karyotypes different from female karyotypes?
8. Compare: In the SIMULATION pane, make sure Subject A is selected. Click on and drag
one of subject A’s chromosomes to the area labeled Identify. Use the arrows to compare
the chromosome you picked with chromosomes 1 through 22 and also with X and Y.
Which chromosome did you select? ____________________________________________
9. Create: Drag the chromosome to the appropriate position on the KARYOTYPING pane.
Then select another chromosome, identify it, and place it on the karyotype.
When you have identified and placed all of the chromosomes, click the camera ( ) to take
a snapshot of the karyotype. Paste the snapshot into a document, and label it “Subject A.”
10. Count: Chromosomes 1 through 22 are called autosomes. Examine the karyotype you have
created. How many total autosomes do human cells have? __________________________
11. Draw conclusions: Look at chromosome pair 23. These chromosomes are known as sex
chromosomes because they determine the sex of an individual. Females have two copies
of the X chromosome. Males have one X chromosome and one Y chromosome.
Examine the karyotype. Is subject A a male or female? _____________________________
How do you know? _________________________________________________________
Click the DIAGNOSIS tab to check your answer.
12. Analyze: Select Subject B from the SIMULATION pane. Complete subject B’s karyotype.
Take a snapshot of the completed karyotype, paste it into your document, and label it.
Examine the karyotype. Is Subject B a male or female? _____________________________
How do you know? _________________________________________________________
Click the DIAGNOSIS tab to check your answer.
6. Think and discuss: On the SIMULATION pane, compare the X and Y chromosomes. Which
chromosome do you think has more DNA? Explain. ________________________________
_________________________________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 37 of 45
Activity B:
Chromosomal
disorders
Get the Gizmo ready:
 Click Reset.
Question: How can you use a karyotype to diagnose a disease?
1. Compare: Select Subject C from the SIMULATION pane. Identify each of subject C’s
chromosomes, and place them on the KARYOTYPING pane. Once you have completed the
karyotype, take a snapshot of it. Paste the snapshot into a document. Label it “Subject C.”
How does subject C’s karyotype differ from a normal karyotype?
_________________________________________________________________________
2. Diagnose: A chromosomal disorder occurs when a person’s cells do not have the correct
number of chromosomes. The table below lists three common chromosomal disorders.
Disorder
Description
Down
syndrome
Extra
chromosome 21
Klinefelter
syndrome
Extra X in male
(XXY)
Turner
syndrome
Single X in
female (XO)
Subject
Symptoms
Use the table to determine which disorder subject C has. Record your diagnosis in the third
column of the table, and then click on the DIAGNOSIS tab to check your answer.
Summarize the information on the DIAGNOSIS tab in the fourth column of the table.
3. Repeat: Complete the karyotypes for Subject D and Subject E. Determine which disorder
each subject has, and use the information from the Gizmo’s DIAGNOSIS tab to complete
the table. Be sure to keep snapshots of both karyotypes.
(Activity B continued on next page)
M-DCPS Grade 7 Science Credit Recovery
Page 38 of 45
Activity B (continued from previous page)
4. Generalize: Another chromosomal disorder, called Edward’s syndrome, occurs when a
person’s cells have three copies of chromosome 18. People who have Edward’s syndrome
are severely mentally retarded and their skeletons are malformed. Most people with
Edward’s syndrome die in infancy.
Use the above information about Edward’s syndrome and the descriptions of Down
syndrome, Klinefelter syndrome, and Turner syndrome in the table on the previous page to
compare these four different chromosomal disorders.
A. Which type of chromosomal disorders seems to have the greatest affect on a
person’s health—disorders involving autosomes or sex chromosomes?
___________________________________________________________________
B. Why do you think this might be the case? __________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
5. Extend your thinking: Klinefelter syndrome only affects males, and Turner syndrome only
affects females. Examine the karyotypes of the subjects you diagnosed with Klinefelter
syndrome and Turner syndrome.
A. How do you think sex is determined in a person with a chromosomal disorder
involving the sex chromosomes? _________________________________________
___________________________________________________________________
B. Individuals with a genetic disorder called trisomy X have three X chromosomes.
(These individuals are normal and do not have any particular symptoms.)
What sex would a person with trisomy X be? _______________________________
6. Summarize: The genome of an organism is its total genetic material. What aspects of the
genome can and cannot be determined through karyotyping?
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 39 of 45
Student Exploration: Mouse Genetics (One Trait)
Vocabulary: allele, DNA, dominant allele, gene, genotype, heredity, heterozygous,
homozygous, hybrid, inheritance, phenotype, Punnett square, recessive allele, trait
Prior Knowledge Questions (Do these BEFORE using
the Gizmo.)
1. The image shows a single litter of kittens. How are they
similar to one another? _________________________
____________________________________________
2. How do they differ from one another? ___________________________________________
3. What do you think their parents looked like? ______________________________________
_________________________________________________________________________
Gizmo Warm-up
Heredity is the passage of genetic information from parents to
offspring. The rules of inheritance were discovered in the 19th
century by Gregor Mendel. With the Mouse Genetics (One Trait)
Gizmo™, you will study how one trait, or feature, is inherited.
1. Drag two black mice into the Parent 1 and Parent 2 boxes.
Click Breed several times. What do the offspring look like?
_________________________________________________
The appearance of each mouse is also called its phenotype.
2. Click Clear, and drag two white mice into the parent boxes. Click Breed several times. What
is the phenotype of the offspring now? __________________________________________
3. Do you think mouse offspring will always look like their parents? ______________________
Explain: __________________________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 40 of 45
Activity A:
Patterns of
inheritance
Get the Gizmo ready:
 Click Clear.
 Drag a black mouse and a white mouse into the
parent boxes, but don’t click Breed yet.
Question: What patterns are shown by offspring traits?
1. Predict: What do you think the offspring of a black mouse and a white mouse will look like?
_________________________________________________________________________
2. Observe: Click Breed several times. What do you see? _____________________________
3. Observe: Drag two offspring into the Holding Cages. These mice are called hybrids
because their parents had different traits. Click Clear, and then breed the two hybrids.
What do you see now? ______________________________________________________
4. Experiment: Turn on Show statistics. Click Breed until there are 100 offspring.
How many offspring were black? ________
How many were white? ________
5. Explore: Try other combinations of mouse parents. Write the results of each experiment in
your notes. When you have finished, answer the following questions. (Note: You can refer to
the parents as “pure black,” “pure white,” or “hybrid.”)
i. Which parent combination(s) yield only white offspring? _______________________
___________________________________________________________________
ii. Which parent combination(s) yield only black offspring? _______________________
___________________________________________________________________
iii. Which parent combination(s) yield a mixture of black and white offspring? ________
___________________________________________________________________
6. Challenge: Based on experiments similar to these, Gregor Mendel devised a theory of
inheritance. Use your own observations to come up with your own explanation of how a trait
such as fur color is passed down from parents to offspring.
Write your explanation down on an extra sheet of paper and attach it to this worksheet. If
possible, discuss your theory with your classmates and teacher.
M-DCPS Grade 7 Science Credit Recovery
Page 41 of 45
Get the Gizmo ready:
Activity B:
Genetics basics
 Click Clear.
 Drag a black mouse and a white mouse into the
parent boxes.
Introduction: Inherited traits are encoded on a molecule called DNA (deoxyribonucleic acid).
Genes are segments of DNA that control a particular trait. Most genes have several different
versions, or alleles. The genotype is the allele combination an organism has.
Question: How do alleles determine fur color?
1. Observe: Turn on Show genotype. Move your cursor over a mouse to see its genotype.
i. What is the genotype of the black parent? _______
White parent? _______
These mice are homozygous for fur color, meaning both alleles are the same.
ii. Click Breed. What is the genotype of the offspring mice? _______
These mice are heterozygous for fur color, meaning the alleles are different.
2. Analyze: Dominant alleles are always expressed when present. Recessive alleles are not
expressed when the dominant allele is also present. Look at the two alleles for fur color.
i. Which allele is dominant, and which fur color does it produce? _________________
ii. Which allele is recessive, and which fur color does it produce? _________________
3. Predict: Place two of the Ff offspring into the Holding Cages. Click Clear, and then place
them into the parent boxes.
i. Which allele(s) could the offspring inherit from parent 1? ______________________
ii. Which allele(s) could the offspring inherit from parent 2? ______________________
iii. What are the possible genotypes of the offspring? ___________________________
___________________________________________________________________
4. Experiment: Click Breed several times, and look at the genotypes of the offspring. Did you
find all the predicted genotypes? Explain.
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 42 of 45
Student Exploration: Building DNA
Vocabulary: double helix, DNA, enzyme, mutation, nitrogenous base, nucleoside, nucleotide,
replication
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
DNA is an incredible molecule that forms the basis of life on Earth. DNA molecules contain
instructions for building every living organism on Earth, from the tiniest bacterium to a massive
blue whale. DNA also has the ability to replicate, or make copies of itself. This allows living
things to grow and reproduce.
1. Look at the DNA molecule shown at right. What does it look like?
_______________________________________________________
This shape is called a double helix.
2. Based on this picture, how do you think a DNA molecule makes a
copy of itself? (Hint: Look at the bottom two “rungs” of the ladder.)
_______________________________________________________
_______________________________________________________
Gizmo Warm-up
The Building DNA Gizmo™ allows you to construct a DNA
molecule and go through the process of DNA replication.
Examine the components that make up a DNA molecule.
1. What are the two DNA components shown in the Gizmo?
________________________________________________
2. A nucleoside has two parts: a pentagonal sugar
(deoxyribose) and a nitrogenous base (in color). When a
nucleoside is joined to a phosphate, it is called a nucleotide.
How many different nitrogenous bases do you see? ________________________________
Note: The names of these nitrogenous bases are adenine (red), cytosine (yellow), guanine
(blue), and thymine (green).
M-DCPS Grade 7 Science Credit Recovery
Page 43 of 45
Activity A:
Build a DNA
molecule
Get the Gizmo ready:
 If necessary, click Reset to start the building
process.
Question: What is the structure of DNA?
Left side
1. Build: Follow the steps given in the Gizmo to
construct a molecule of DNA. (Note: For simplicity,
this DNA molecule is shown in two dimensions,
without the twist.)
Stop when the hint reads: “The DNA molecule is
complete.” In the spaces at right, list the sequence
of nitrogenous bases on the left-hand side of the
DNA molecule and the right-hand side.
Right side
_____________ _____________
_____________ _____________
_____________ _____________
_____________ _____________
_____________ _____________
_____________ _____________
2. Take a picture: Click the camera ( ) at upper right
to take a snapshot of your DNA molecule. Open a
blank word-processing document, and select
paste. Label this image “Original DNA molecule.”
M-DCPS Grade 7 Science Credit Recovery
_____________ _____________
_____________ _____________
Page 44 of 45
3. Explain: Describe the structure of the DNA molecule you made.
i. What makes up the sides of the DNA molecule? ____________________________
ii. What makes up the “rungs” of the DNA molecule? ___________________________
4. Fill in: Write the name of the nitrogenous base that joins to each of the bases below:
Adenine (A) joins to _______________
Thymine (T) joins to _______________
Cytosine (C) joins to _______________
Guanine (G) joins to _______________
5. Practice: The left side of a DNA molecule is shown. Draw a
complementary right side of the molecule.
6. Challenge: This DNA strand consists of eight pairs of nitrogenous
bases. How many different sequences of eight bases can you
make? Explain how you found your answer.
____________________________________________________
____________________________________________________
M-DCPS Grade 7 Science Credit Recovery
Page 45 of 45
Non-Discrimination Policy
The School Board of Miami-Dade County, Florida adheres to a policy of nondiscrimination in employment and
educational programs/activities and strives affirmatively to provide equal opportunity for all as required by:
Title VI of the Civil Rights Act of 1964 - prohibits discrimination on the basis of race, color, religion, or
national origin.
Title VII of the Civil Rights Act of 1964 as amended - prohibits discrimination in employment on the basis of
race, color, religion, gender, or national origin.
Title IX of the Education Amendments of 1972 - prohibits discrimination on the basis of gender.
Age Discrimination in Employment Act of 1967 (ADEA) as amended - prohibits discrimination on the basis
of age with respect to individuals who are at least 40.
The Equal Pay Act of 1963 as amended - prohibits gender discrimination in payment of wages to women and
men performing substantially equal work in the same establishment.
Section 504 of the Rehabilitation Act of 1973 - prohibits discrimination against the disabled.
Americans with Disabilities Act of 1990 (ADA) - prohibits discrimination against individuals with disabilities
in employment, public service, public accommodations and telecommunications.
The Family and Medical Leave Act of 1993 (FMLA) - requires covered employers to provide up to 12 weeks
of unpaid, job-protected leave to "eligible" employees for certain family and medical reasons.
The Pregnancy Discrimination Act of 1978 - prohibits discrimination in employment on the basis of
pregnancy, childbirth, or related medical conditions.
Florida Educational Equity Act (FEEA) - prohibits discrimination on the basis of race, gender, national origin,
marital status, or handicap against a student or employee.
Florida Civil Rights Act of 1992 - secures for all individuals within the state freedom from discrimination
because of race, color, religion, sex, national origin, age, handicap, or marital status.
Title II of the Genetic Information Nondiscrimination Act of 2008 (GINA) - Prohibits discrimination against
employees or applicants because of genetic information.
Veterans are provided re-employment rights in accordance with P.L. 93-508 (Federal Law) and Section 295.07
(Florida Statutes), which stipulate categorical preferences for employment.
In Addition:
School Board Policies 1362, 3362, 4362, and 5517 - Prohibit harassment and/or discrimination against
students, employees, or applicants on the basis of sex, race, color, ethnic or national origin, religion, marital
status, disability, genetic information, age, political beliefs, sexual orientation, gender, gender identification,
social and family background, linguistic preference, pregnancy, and any other legally prohibited basis.
Retaliation for engaging in a protected activity is also prohibited.
Revised: (05-12)