Xtreme STEM
DashX

Red Hot Knife vs Ice

Introduction

Today you are going to see what happens when hot meets cold!

Last week you learned how to calculate the energy it takes to change the temperature of something.

Don't forget that any time sometime changes states/phases it also takes a lot of energy!

What do we call the hidden energy it takes to boil a substance
LIQUID ←→ GAS (Vapour)
The of

 

What do we call the hidden energy it takes to melt a substance
LIQUID ←→ SOLID
The of

 

Tries: 0

 

1) Hot Water vs Cold Water

  1. Eye Protection On
  2. Measure 50g of cold water
  3. Measure 50g of hot water
  4. Measure the initial Temperature of cold water: °C
  5. Measure the initial Temperature of hot water: °C
  6. Predict the Temperature of mixed water: °C
  7. Predict the "winner":
  8. Pour them both into a cup
  9. Mix with the themometer for a minute
  10. Measure the final Temperature of mixed water: °C

ΔT = Tfinal - Tinitial
+ Positive = Temperature went up (Gained Heat)
- Negative = Temperature went down (Lost Heat)

How much did the temperature of the cold water change?
ΔTcold = °C

How much did the temperature of the hot water change?
ΔThot = °C

 

Which was the "winner":

What is your theory for why that happened?
Told Mr Dash your theory

 

Tries: 0

2) Hot Water vs Ice

  1. Eye Protection On
  2. Measure 50g of ice
  3. Measure 50g of hot water
  4. Measure the initial Temperature of ice: °C
  5. Measure the initial Temperature of hot water: °C
  6. Predict the Temperature of mixed water: °C
  7. Predict the "winner":
  8. Mix them both in a cup
  9. Mix with the themometer until all ice has melted
  10. Measure the final Temperature of mixed water: °C

ΔT = Tfinal - Tinitial
+ Positive = Temperature went up (Gained Heat)
- Negative = Temperature went down (Lost Heat)

 


How much did the temperature of the ice change?
ΔTice = °C

How much did the temperature of the hot water change?
ΔThot = °C

 

Which was the "winner":

What is your theory for why that happened?
Told Mr Dash your theory

 

Tries: 0

3) Hot Metal vs Water

  1. Eye Protection On
  2. Get a 10¢ coin
  3. Measure the mass of the coin g
  4. Measure 10g of cold water (from the fridge) into a small cup
  5. Measure the initial Temperature of cold water: °C
  6. Temperature of red hot metal: 825C
  7. Predict the Temperature of water: °C
  8. Predict the "winner":
  9. Gloves on
  10. Ask Mr Dash to help you heat a coin until it is red-hot!
  11. Drop the red-hot coin into the cup of water
  12. Mix with the themometer until equilibrium is reached
  13. Measure the final Temperature of the water: °C

 

Which was the "winner":

What is your theory for why that happened?
Told Mr Dash your theory

 

Tries: 0

4) Red Hot Knife vs Ice

  1. Eye Protection On
  2. hot vs coldGet an ice cube
  3. Measure the mass of the ice cube g
  4. Temperature of red hot metal: 825°C
  5. Predict what percentage of the ice you will be able to melt with the red-hot knife: %
  6. Predict the "winner":
  7. Gloves On
  8. Ask Mr Dash to help you heat the knife until it is red-hot!
  9. Now melt as much of the icecube as possible

 

Which was the "winner":

What is your theory for why that happened?
Told Mr Dash your theory

 

Tries: 0

Clean-up

  1. Empty all water and ice into the sink
  2. Remove the coin from the water and return it
  3. Return all equipment
  4. Remove Eye Protection, place in bag, and place in the container

 

Did you tidy everything?

 

Tries: 0

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