Molecular Motion
Definition of Molecular Motion
the constant, random movement of individual molecules within a substance, driven by their kinetic energy
As coffee warms up, the ___________ of the particles _________________.
A. kinetic energy
B. decreases
C. increases
D. potential energy
As coffee warms up, the kinetic energy of the particles increases.
Definition of thermal energy
The TOTAL energy of all moving particles in an object.
The transfer of heat through direct contact (touching) between objects
Conduction
A hot air balloon rises because of this heat transfer process
Convection
If the temperature of boil water increases, the _____________ of the particles in the water also increases.
A. kinetic energy
B. potential energy
C. thermal energy
kinetic energy
A winter animal shelter should do which of the following?
A. Allow lots of energy to transfer out of the shelter
B. Prevent energy from transferring out of the shelter
Prevent energy from transferring out of the shelter
Heat energy flows in this direction between objects
WARM TO COOL
Heat transfer through fluids like air or water involves this process.
Convection
What allows us to feel the warmth of a campfire from a distance
radiation
What happens to the temperature and particles of 65 degrees water if thermal energy is removed?
The temperature decreases, and the particles move more slowly.
Which would be a more effective lining for an animal shelter? And why?
Blankets vs. crumpled newspaper
Blankets are a more effective linking because they reduce energy transfer
This form of energy transfer does not involve direct contact. It transfers through electromagnetic waves.
radiation
Name two common insulators that slow heat transfer
Included but not limited to (foam, wood, or plastic)
Why does a black car feel hotter than a white car when left in the sun?
Black surfaces absorb more heat from sunlight, while white surfaces reflect most of the light, keeping them cooler.
How is molecular movement related to pressure?
Increase in molecular movement leads to an increase in FORCE which results in increased pressure.
A metal spoon is left in a pot of boiling water on the stove. After a few minutes, the handle of the spoon becomes too hot to touch. Explain what type of heat transfer is responsible for this and why the heat moves to the handle.
The heat is transferred from the hot water to the spoon's handle through direct contact between the metal molecules, which conduct heat efficiently.
When dough is heated in the oven, it rises and becomes puffier. How does thermal energy affect the dough, and what happens to its potential energy as it rises?
Thermal energy heats the dough, making the gases inside it expand, causing the dough to rise. As it rises, its potential energy increases because it is getting higher off the surface.
What happens to an object if thermal energy is removed.
Discuss molecular motion and temperature.
Molecules slow down, temperature decreases
In a cold environment, a house with thick insulation stays warmer inside than a house with thin walls and no insulation. Explain how insulation helps prevent heat loss.
Insulation traps air, which is a poor conductor of heat, and prevents warm air inside the house from escaping. It also slows down convection by limiting air movement through the walls.
When a metal rod is heated at one end, the other end eventually becomes warm. Explain what happens to the molecules in the metal and how this transfer of energy leads to the warming of the entire rod.
As the metal rod is heated, the molecules at the hot end move faster and collide with adjacent molecules, transferring their energy. This process continues along the rod, causing the molecules in the cooler parts of the rod to speed up, warming the entire rod.
A student just got done making a pot of hot cocoa. They want the cocoa to cool down as quickly as possible so they can drink it right away. What material should their mug be made out of so that it cools down quickly?
Metal
What is the relationship between thermal energy, kinetic energy and temperature within a substance?
Taking away thermal energy will decrease kinetic energy and the temperature will decrease.
Adding thermal energy will increase kinetic energy and the temperature will increase.
What do you call a blanket in an outdoor animal shelter? How might an animal increase the lining of their outdoor animal shelter?
Insulator ; Open ended
During winter, animals like polar bears stay warm because their fur traps air close to their bodies. How does this help reduce heat loss?
The trapped air acts as an insulator because air is a poor conductor of heat, keeping the animal’s body heat from escaping.