Thermal Energy & Heat
What is the total kinetic and potential energy of all the particles in an object?
It's thermal energy
A measure of the average kinetic energy of the particles in a substance.
What two factors determine how much thermal energy two containers of tea have?
mass and temperature
What are the three ways heat can be transferred. Give an example of each.
Conduction: pot touching a stove
Convection: Water in pot transferring heat from warmer molecule to cooler molecule.
Radiation: Sun's transfer of energy to Earth
Explain what a conductor is and give an example.
A conductor is a material that conducts heat well. Ex. Metals like silver.
What is the energy that is transferred from warm to cool objects called?
Heat
In an object, how do particles move when the objects temperature is higher vs lower?
When the objects temperature is higher the particles move faster than when the temperature is lower.
Which has more thermal energy, a cup of water at 39 degrees C or a cup of water at 60 degrees C? Explain.
The cup at 60 degrees, the cups of water have the same mass, but the one at higher temperature has more thermal energy.
Which type of heat transfer occurs in the ocean? Explain.
Convection: because it is a liquid.
Explain what an insulator is and give an example.
An insulator is a material that does not conduct heat well. An example is air or wool.
Does warm ocean water have more thermal energy than the same amount of cool ocean water? Explain.
Yes. The particles in warmer water move more quickly and therefore have more kinetic energy.
A thermometer.
Which has more thermal energy, a bathtub full of water at 39 degrees C or a cup of water at 39 degrees C. Explain.
The bathtub; both have same temperature but because bath has more mass it has more thermal energy (more particles).
If a beach is hotter than the lake water that is it next to, explain how this affects heat transferred by convection in the air.
The air over the beach will heat up more quickly and rise up farther than air over the cooler lake.
How does friction between a bike tires and the ground relate to thermal energy and temperature?
Friction increases the thermal energy, and temperature of both the bike tires and the ground.
Explain how heat is transferred in a glass with tea and ice.
What are the three units temperature can be measured in and which two do we use in science class?
Celsius, Fahrenheit and Kelvin. In science class we use either Celsius or Kelvin.
You have two burritos both with same ingredients. One burrito is 1lb and the other is 2lbs. After microwaving each of them for 1 minutes which will be hotter. Explain.
The 1lb burrito will be hotter. The larger burrito requires more heat to heat it up to the same temperature as the smaller one. So larger one will be cooler.
What is another way of saying that energy can transform?
It can change forms; it can turn into other forms.
Which type of material should be used to keep an airplane warm inside and why?
An insulator because it will prevent heat from transferring to the atmosphere/air.
How does thermal energy relate to temperature during condensation?
The thermal energy of the gas decreases, but it's temperature remains the same initially, so TE will decrease much faster than temperature.
What happens when heat is added to a substance and there is not change in the state of matter? Explain what three things increase.
Kinetic energy of particles increases; temperature increases; thermal energy increases.
What is the minimum value for the Kelvin temperature scale, and what would happen at that temperature?
It is zero, and at zero all the motion of all the particles would stop completely.
Describe the energy transformations involved in heating soup in a microwave. Which method of heat transfer is involved in heating the soup?
The microwave transforms electricity into light energy. The light energy heats the soup via radiation, and the radiation transforms into the thermal energy of the soup.
When an object slows down due to friction, what energy transformation takes place?
Kinetic energy is transformed to thermal energy.