I’m so hot Chill out, man Counting Calories

Going through a phase

I’m not a category

1 1 1 1

2 2 2 2

3 3 3 3

4 4 4 4

5 5 5

I’m So Hot 1

• Heat is what form of energy?

I’m so Hot 1

• Kinetic

I’m So Hot 2

• Heat is measured in what units? (name 2)

I’m so Hot 2

• Calories or Joules

I’m so Hot 3

• If you paint a thermos bottle silver on the outside, what type of heat transfer are you trying to reduce? Why/how?

I’m So Hot 3

• Radiation: to reflect it

I’m So Hot 4

Why is the water cooler at the bottom of the lake in the summer?

What form of heat transfer is related to this?

I’m so Hot 4

• Fluids that are cool are dense and sink to the bottom of their containers. This drives convection

I’m so Hot 5

• Does the pressure of the air in car tires change as you drive? If so, does it go up or down and why would it?

I’m so Hot 5

• Goes up. Friction with road causes heating of air in tires which increases the pressure.

Chill Out, Man 1

• The cold temperature of -200 degrees Celsius equals what on the Kelvin scale?

Chill Out, Man 1

• 73 Kelvin

Chill Out, Man 2

• If you want to freeze 20 mL of water, how many calories do you need to remove from the water if it’s at 0 deg C?

Chill Out, Man 2

• 20 g * 80 cal/g = 1600 cal

Chill Out, Man 3

• A 10 g piece of glass gets cooled from 30 degrees C down to 20 degrees C. Its specific heat is .20 cal/g*degrees C. How much heat was lost by the glass?

Chill Out, Man 3

• 10 g * (-10 °C) * .2 cal/g °C)= - 20 cal

Chill Out, Man 4

• Which would be better to use for cooking a big pot of pasta sauce: A Steel or copper pot?

• Defend your answer.• Hint: You cook it for a long time but don’t

want to burn the bottom of the sauce.

Chill Out, Man 4

• Iron.

Chill Out, Man 5

• Use the word “insulate” to explain why it is so difficult for scientists to make a substance reach absolute zero.

Chill Out, Man 5

Heat always manages to get into the substance. It’s really difficult to insulate heat from getting through to the experiment.

Counting Calories 1

• A chemical reaction takes place in a calorimeter. The following data are obtained:

• Mass of water: 500 g• Initial Temp of water: 30 degrees C• Final Temp of water: 45 degrees C

Counting Calories 1

• 7500 cal

Counting Calories 2

• Where does the word “calorie” come from?

Counting Calories 2

• Scientists originally thought heat was an invisible fluid called “caloric”

Counting Calories 3

• What is the specific heat of water?

Counting Calories 3

• 1 cal/g °c

Counting Calories 4

True or false: A thermometer measures calories.

Counting Calories 4

• False

Counting Calories 5

• A Big Mac with 550 Calories is how many calories?

Counting Calories 5

• 550,000 calories

Going through a phase1

• Gases ________when heated and ______when cooled.

Going through a phase 1

• expand

• contract

Going through a phase 2

• If you skip going from a solid and go straight to a gas, it’s called:___________

• The opposite is called:_________________

Going through a phase 2

• Sublimation• deposition

Going through a phase 3

• The heat you have to add to water at its boiling point in order to get it to turn into a gas is known as _______________

• Its value is: ____________

Going through a phase 3

• Heat of vaporization• 540 cal/gram

Going through a phase 4

• Answer 3 a b c d and e on page 39 in text.

Going through a phase 4

• C• A and B• C has faster molecules, on average• The same• Containers B & C

Simply working it 5

• Scissors 1st

• Hockey Stick 3rd• Wheelbarrow 2nd• Pliers 1st

Energizer Bunny 1

• List which of the five forms of energy are potential

• Then, list which of the five forms of energy are kinetic

Energizer Bunny 1

• Potential: nuclear and chemical• Kinetic: heat, electromagnetic, mechanical

Energizer Bunny 2

• If an object has a mass of 50 kg and is moving at 2 m/s, what is its kinetic energy?

• If the same object is held 3 meters high above the ground what is its gravitational potential energy?

Energizer Bunny 2

• 100 J• 1470 J

Energizer Bunny 3

• After the car is lifted up the first hill, a rollercoaster runs on gravity. If the energy of the coaster is equal to its starting GPE, why must the rest of the hills be lower in height than the first?

Energizer Bunny 3

• Because of the law of conservation of energy, the coaster’s height on successive hills can never be higher than the starting, otherwise, it would be gaining energy.

• In fact, it loses a lot of energy as noise and heat due to friction as it travels: requiring even lower hills later

Energizer Bunny 4

• Describe an energy conversion that involves turning mechanical energy into heat.

Energizer Bunny 4

• Rubbing hands

Energizer Bunny 5

• If a ball is thrown upward into the air at a release height of 2 meters, goes up, then falls back to earth, its speed at its starting height is:

• A) greater than the speed thrown at (because of gravity)

• B)less than the speed thrown at (because of friction

• C) equal to the speed thrown at (just because)

Energizer Bunny 5

• C: KE at that height is equal (what you put into system is what you get out…..energy is conserved.)