Why do molecules change speed?

• Molecules change speed when they are at equilibrium

• Molecules speed up when they get energy from other molecules

• Sample A is hotter then sample B

• Molecules slow down when they give energy to other molecules

Answer explanation

Molecules change speed due to energy transfer. They speed up when they absorb energy from other molecules and slow down when they transfer energy to other molecules, affecting their kinetic energy.

Tags

NGSS.MS-PS1-4

A 65 degree sample makes contact with a 35 degree sample, how will the systems react?

• The red will get hotter along with the black

• The red will get hotter with energy from the black until they are equal

• The black will get colder with energy from red until they equal

• The black will share energy with the red forever

Answer explanation

When a 65 degree sample (red) contacts a 35 degree sample (black), energy transfers from the black to the red until they reach thermal equilibrium, making the red hotter until both are equal.

Tags

NGSS.MS-PS1-4

Why does the transfer of energy between two colliding things stop?

• Molecules stop transferring energy when colliding systems reach equilibrium

• When the two non-colliding things get equally hot molecules make energy

• Molecules make more kinetic energy until it is balanced

• The molecules of a system destroy energy when the system is balanced

Answer explanation

Molecules stop transferring energy when colliding systems reach equilibrium, meaning they have equal energy distribution and temperature, resulting in no net energy transfer between them.

Tags

NGSS.MS-PS3-5

How do air conditioners cool the air?

• Air conditioners cool air by air slowing molecules down.

• Air conditioners cool air by speeding air molecules up.

• Reaching Equilibrium at the same time

• Creating hot air instead of cold air

Answer explanation

Air conditioners cool air by slowing down air molecules, which reduces their energy and temperature. This process effectively lowers the air temperature, making the environment cooler.

Tags

NGSS.MS-PS1-4

Imagine that your Mom just put a frozen Bubba-Burger on the hot grill to sizzle? In energy terms what is happening?

• The Bubba-Burger molecules are transferring energy to the grill

• The Bubba-Burger is at equilibrium with the grill

• The grill molecules are transferring energy to the Bubba-Burger

• The grill is creating energy with the Bubba-Burger

Answer explanation

The grill molecules are transferring energy to the Bubba-Burger, causing it to heat up and cook. This is a process of heat transfer from the hotter grill to the colder burger.

Tags

NGSS.MS-PS1-4

Your family orders a pizza from Dominoes during CoVid19, the driver left the bag open. The pizza is cold. What happened?

• The energy in the molecules of the pizza decreased

• The pizza lost heat molecules

• The cold energy in the molecules of the pizza increased

• The energy in the molecules of the pizza increased

Answer explanation

The pizza became cold because the energy in its molecules decreased as it was exposed to the cooler air outside the bag. This loss of heat energy resulted in a lower temperature for the pizza.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

A 65 degree sample makes contact with a 35 degree sample, at what temperature will the systems be at equilibrium?

• 45

• 30

• 50

• 55

Answer explanation

To find the equilibrium temperature, use the average of the two temperatures: (65 + 35) / 2 = 50. Thus, the systems will be at equilibrium at 50 degrees.

Tags

NGSS.MS-PS1-4

If a 40 and a 90 degree cup of coffee sit out on a 30 degree day, which cup will likely be warmest after 10 minutes?

• The 90 degree cup becasue it transferred energy to the colder air

• The 90 degree cup because it got energy from the colder air

• The 40 degree cup because it got energy from the colder air

• The 40 degree cup because it transferred energy to the colder air

Answer explanation

The 90 degree cup will likely be warmest after 10 minutes because it transfers energy to the colder air more rapidly than the 40 degree cup, which is already closer to the ambient temperature.

Tags

NGSS.MS-PS1-4

When an object gets colder, its molecules move...

• slower

• faster

• the same

• it changes

Answer explanation

When an object gets colder, its molecules lose energy and move slower. This decrease in kinetic energy results in reduced molecular motion, making 'slower' the correct choice.

Tags

NGSS.MS-PS1-4

When two things are in contact, kinetic energy transfers...

• from slow-moving molecules to faster-moving molecules.

• from fast-moving molecules to slower-moving molecules.

• between the two things.

• nowhere and disappears

Answer explanation

When two things are in contact, kinetic energy transfers from fast-moving molecules to slower-moving molecules, as energy naturally flows from areas of higher energy to areas of lower energy.

Tags

NGSS.MS-PS3-5

NGSS.MS-PS3-1