Title: Ice
1 Reporter Hsieh, Tsung-Lin
2Question
- A wire with weights attached to each end is
placed across a block of ice. - The wire may pass through the ice without cutting
it. - Investigate the phenomenon.
3Outline
- Experimental setup
- Typical results
- Hypothesis
- Pressure effect
- Weight
- Thermal conductivity
- Curvature
- Other effect
- Summary
4Experimental Setup
Ice
Camera
Weights
5Typical Result
- The wire position is obtained by MATLAB program.
Duration 1 hr
6Pressure Effect
- Ice under the wire tends to melt.
Heat
7Schematic Phase Diagram
Pressure
Liquid
Atmospheric pressure
Ice
Solid
Gas
Temperature
8Schematic Phase Diagram
Pressure
IceWater
Absorbing heat
Cutting
Liquid
Atmospheric pressure
Solid
Gas
Temperature
9Schematic Phase Diagram
Pressure
Releasing heat
Liquid
Atmospheric pressure
Ice
Solid
Gas
Temperature
10Pressure effect
- Weight
- Thermal conductivity
- Curvature
11Speed at Center
- Speed of the center of the wire after it sinks
into the ice.
distance
12Weight
Stainless steel wire 0.4mm
- 3kg 0.11
- 4kg 0.18
- 5kg 0.26
- 6kg 0.30
- 7kg 0.39
- 8kg 0.49
- (cm/min)?
13Weight vs. Speed at Center
Stainless steel wire 0.4mm
Pressure
l
s
g
Temperature
14Mathematical Estimation
- Heat conducting rate
- From Clausius-Clapeyron equation,
- Center speed upper limit
- Pressure effect plays an important role.
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16Material vs. Speed at Center
- Thermal Conductivity
- (W/m-K)?
- Aluminum 235
- Steel 16.3
speed 0.34 cm/min
speed 0.30 cm/min
- Good thermal conductor cuts faster.
17Water Flow Video
18Wire Diameter
- 0.3mm 0.30
- 0.4mm 0.18
- 0.6mm 0.06 (cm/min)?
19Pressure and Curvature
T
T
?
?
r
?
?
d
Cross-section of the Wire
Ice
20Cutting Speed
- After the whole wire sinks into the ice
Pressure effect dominates
External heat input is more significant
Left side
center
21External Heat Effect
- Water melts due to external heat input
- It can solidify again because the temperature
inside the ice is below 00C (-150C -0.60C).
Hot
Cold
External heat
22Summary
- The wire passes through the ice
- Pressure effect
- External heat effect
- The ice regelates (without being cut)
- Pressure releases
- Temperature inside the ice is below 00C
23Thank you for your attention.
24Ambient Temperature
- The speed at center is almost constant.
- Repeatable in different temperature (230C280C).
- Ambient heat can be neglected.
25Weight
- 6kg 0.12
- 4kg 0.06
- 3kg 0.05
- (cm/min)?
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27Temperature inside the Ice
28Time interval 5 min
29Time interval 5 min
30Curvature vs. Speed
- At the Beginning of Cutting
Pressure effect dominates
Left side
center
31Patterns formed on regelated ice
32Problems on the Hypothesis
- Water can be supercooled and it dont have to
follow the phase line. - Of course not, but the final state is, as
observed. - The direction of pressure
- The cross-section shape of the wire
- The surface property (roughness) of the wire
- It takes some time for it to travel along the
phase line. - In our case, it is a good assumption.
- Heat may flow to not only the ice below it.
- There may be water flow.
- My position error? Less than 5
- What about put the ice in 00C?
- Wire moving causes cutting, not only pressing.
- Does your wire has the same diameter after
hanging weights? - PICK UP the main physics
33Speed v.s. Curvature at time 1
- In the middle of the ice, speed is positively
related to the curvature. - The speed is faster at both side because of
external heat.
Fig. Acceleration
Fig. Speed of the whole wire
34Speed v.s. Curvature at time 2
- In the middle of the ice, speed is positively
related to the curvature. - The speed is faster at both side because of
external heat.
Fig. Speed of the whole wire
Fig. Acceleration