Science Force – 3rd Grade – Energized Bobcats
(ANSWER KEY)
Take Your Mind for a Spin
Rattlebacks
1. Press lightly on the end of a blue, red, or yellow rattleback. Which
direction did the rattle move?
LEFT or RIGHT
2. Try each color rattle. Try pressing lightly on each end. Which direction
did the rattlback move each time? LEFT or RIGHT
3. Try to spin the rattle to the right. What happened?
ANSWER: It spins for a second, then rattles, then reverses and spins
counterclockwise.
4. Can you explain what happened?
ANSWER: The Coriolis force of nature – Anything in the Northern
Hemispher (above the equator, top ½ of the Earth) spins, slants, or turns to
the left. Flush your toilet when you go home & see what happens. (Note:
Anything in the Southern Hemisphere spins clockwise.)
Swinging Apparatus
1. What happened when you pulled one of the steel balls away from the
others and let go?
ANSWER: It hit the other balls and one ball on the opposite end swung
out….then hit the others and one ball on the opposite side swung out again.
EXPLANATION: When the 1st ball hit, energy was transferred through
each ball until it reaches the end and then back again until all energy was
used up.
2. What happened when you pulled two of the steel balls away from the
other and let them go?
ANSWER: Same as above except 2 balls swung out.
3. What other experiments did you try?
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4. What happened?
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Science Force – 3rd Grade – Energized Bobcats
Radiometer
Try these experiments!
1. Look carefully at the black and white vanes in the bulb. Are they moving
when the bulb is sitting on the table under the light? A little.
2. Shine the flashlight on the bulb. What happens?
ANSWER: They move faster.
3. Shine two flashlights on the bulb. Is there any change?
ANSWER: They move even faster.
4. Put the bulb under the table (away from the light). What happens to the
vanes? ANSWER: They stop moving.
5. Turn the hair dryer on and direct the heat towards the bulb. What
happens? ANSWER: They move very fast.
6. Blow on the bulb with a drinking straw. What happens?
ANSWER: Nothing. The vanes don’t move.
7. What do you think happens to make the vanes move?
ANSWER: When heat or light energy is applied, the molecules inside
speed up. The black vanes absorb the heat, the white vanes reflect the
heat. The molecules between the vanes go back and forth causing the
vanes to move.
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Science Force – 3rd Grade – Energized Bobcats
(ANSWER KEY)
APOLLO!
SUN PRINTS
Directions:
1. Get 1 piece of sun print paper and place it on top of cardboard blue side
up.
2. Select 2 items from each tray (1, 2 &3) and place on top of blue paper.
3. Carefully sit the cardboard with sunprint paper & items outside on the
deck.
4. When paper turns white, bring inside, carefully remove objects and place
in water.
5. When paper begins to turn back to blue, remove from water, place in
dryer.
PREDICT
1. Which object(s) do you think will make the best picture on the sun print
paper?
RESULT
2. What was your finding? Which object(s) made the best picture?
ANSWER: Any of the solid / opaque materials made the best picture –
button, shell, beans because they block the light. The lens and straws are
translucent or clear and the sun penetrates them, so they do not make as clear
of an imprint.
CONCLUSIONS
What do you think happened when you placed the paper in the sun?
ANSWER: Heat from the sun changed the color of the paper = Chemical
Energy. When it is brought inside and placed in water, it cools and changes
back.
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Science Force – 3rd Grade – Energized Bobcats
(ANSWER KEY)
UV POLICE
Using a UV Meter, hold it up to the window.
1. What amount of UV rays were present?
ANSWER: 1-8 (what is this unit of measure?)
Take the UV meter outside.
2. What amount of UV rays were present outside?
ANSWER:
Can you explain why there is a difference?
ANSWER: The window is made of a material that prevents UV rays.
UV MAGIC
Make a UV bracelet by stringing 4 beads onto a pipe cleaner. Have a friend
secure the bracelet to your wrist.
1. What color are the beads on your bracelet?
2. Go outside. Now what color are your beads?
3. Now, go back inside. Wait 2-3 minutes. What color are your beads?
4. Can you explain?
ANSWER: The beads are made from a chemical that reacts to UV rays.
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Science Force – 3rd Grade – Energized Bobcats
(ANSWER KEY)
Don’t Lose Your Marbles
Experiment #1
Make sure an “object” is placed at the end of each “road”(ruler). Release the marble
from the top of each “road”. PREDICT FIRST!
Predict
2. On which road will the marble move the object the farthest?
Road 1
Road 2
Road 3
Result
3. On which road did the marble move the object the farthest?
Road 1
Road 2
Road 3
ANSWER: Road 3
4. Can you explain why this happened?
ANSWER: The faster something moves, the more kinetic energy it has. When it
hits the yellow car, it will move it further.
Experiment #2
For this experiment, put 3 marbles in the yellow “car” and try the same experiment that
you did in Experiment #1.
Predict
1. What do you think will happen when you put 3 marbles in the yellow car?
a. the car will fall over
b. the car will move farther
c. the car will not move as far
Result
2. What happened when you added 3 marbles to the car?
ANSWER: C
3. Can you explain this?
ANSWER: The greater the mass of an object, the more the kinetic energy will be
absorbed. It will not move as far.
Extension:
Try different marbles that roll down the road. Does it make a difference which marble
you use?
ANSWER: The larger, heavier object will move it farther because it has more energy.
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Science Force – 3rd Grade – Energized Bobcats
Experiment #3
For this experiment you will release the 2 steel balls at exactly the same time and observe
to see which one hits the wooden block FIRST. You must do the experiment 3 times
to make sure the data is correct.
Predict
1. On which steel road A or B, will the steel ball reach the wood block 1st? A
or B
Result
2. On which steel road A or B, did the steel ball reach the wood block 1st?
ANSWER: B
3. Can you explain why this happened?
ANSWER: The incline or curves in the road allow the steel ball to gain momentum and
thus more kinetic energy.
Which is Which?
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Science Force – 3rd Grade – Energized Bobcats
Electrical
Energy
Stored
Energy
Sound
Energy
Chemical
Energy
Heat
Energy
Solar
Energy
Battery
Light Stick
Whistle
Light Stick
Light Stick
Calculator
Flashlight
Granola
Bar
Charcoal
Slinky
Charcoal
Thermometer
Solar Panel
Mallet
Match
Hot Plate
Pencil
Sharpener
Hot Plate
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Wind-up
Car
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Science Force – 3rd Grade – Energized Bobcats
Potato Clock
Experiment with all the electrodes and the potato and oranges to see if you
can make the clock come on. If you get the clock to come on, explain
exactly what you did.
ANSWER: 1 zinc and 1 copper in each potato or orange. Acid in the
potato or orange creates an electrical current. Like a battery, the zinc is
the negative charge and the copper is the positive charge which absorbs
the energy or electrons.
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