Flinker - MTU Mind Trekkers

MIND TREKKERS
Flinker (neutral buoyancy)
Amount of time Demo takes: 2-5 min
# times per hour: 20
Materials
1. Styrofoam peanuts (1/demo)
2. String (1 roll/day)
3. Scissors (3)
4. Masking tape (1 roll/day)
5. Washers (30, reuse!)
6. Wood beads(50, reuse!)
7. Large see-through fish tank or
very clear plastic container
8. Water (to fill tank)
9. Permanent markers (box)
10. Bucket for water
11. Gloves
12. Spoon
Set up instructions:
1. Fill up container with water
2. Spread out supplies on the table for students to access
3. Create a sample flinker and place it in water
4. Remember, a flinker's a flinker because it doesn't float, it doesn't sink, it flinks!
SAFETY!
1. Assist small children with scissors.
2. Clean up any major water spills on the floor in front of demo (if slick surface).
Lesson’s big idea bullet points
Neutral buoyancy: Flinkers ‘flink’ when they achieve neutral buoyancy - a
condition in which a physical body's mass equals the mass it displaces in a
surrounding medium. This offsets the force of gravity that would otherwise
cause the object to sink. An object that has neutral buoyancy will neither sink
nor rise.

Instructional Procedure
1. When students arrive ASK: “Can you make a "flinker" - something that you put in a pitcher
of water that doesn't float on the top or sink to the bottom, but just flinks in the middle of the
water”
2. Tell them, “Your flinker should flink for 10 seconds.”
3. Encourage students to design their own flinker using styrofoam peanuts, string and
washers or wood beads. Allow students to customize their flinker by giving it a face with the
permanent markers.
4. Once the flinker is finished tell the students to test it in the water.
5. If the flinker doesn’t “flink” encourage students to change one thing at a time in their design
until their flinker “flinks.” ASK: “What can you change to make it flink Could you attach
washers or wood beads to your Styrofoam peanut with string Or, could you change the shape of
the Styrofoam”
6. Try to get flinkers to flink for 10+ seconds.
7. If multiple students are around, hold a competition to see whose flinker can flink the longest.
Clean Up
1. Discard used flinkers; collect washers and wood beads for reuse.
2. Make sure all permanent markers are accounted for and returned to container or banded
together.
3. Discard the water and wipe out the container.
4. When completely finished gather all materials listed for this demonstration and make sure
everything is accounted for. If something was used up, broken or damaged, let someone know so
it can get replaced or fixed.
References:
http://pbskids.org/zoom/activities/sci/flinker.html
National Standards
K-4 Content Standard B: Physical Science, Properties of objects and materials
5-8 Content Standard B: Physical Science, Properties and changes of properties in matter
9-12 Content Standard B: Physical Science, Structures and properties of matter, interactions between
energy and matter