vacuum flask

Vacuum flasks usually have silvered walls that help to keep the contents of the flask hot.

Why are the walls silvered?

• to absorb thermal energy from the air around the flask

• to increase the rate of convection inside the flask

• to reduce energy loss to the surroundings by conduction

• to reflect thermal radiation back into the flask

Which of the following is an example of heat transfer by conduction?

• sunlight hitting a floor

• an electric stove heating an iron pan

• a wood stove heating nearby objects

• an electric heater heating air, which rises and is replaced with cooler air

A rise in the temperature inside a kitchen means there is an increase in the

• density of air molecoles

• number of air molecoles

• average size of the air molecoles

• average kinetic energy of air molecules

Which of the following identifies a heat transfer primarily due to radiation?

• from the wall of the pan to the cover

• from the pan to the surface of the water

• from the flame to the bottom of the pan

• from the surface of the water to wall of the pan

The diagram shows a liquid in a stoppered flask. The flask is submerged in hot water. What will happen to the liquid inside of the flask?

• Heat will make the liquid expand inside the flask.

• Gravity will push the liquid up.

• Air bubbles are released.

• Air pressure pulls the liquid up.

What observation can you make about what happened to the snowman?

• It changed from a liquid to a solid
• It changed from a liquid to a gas.
• It changed from a gas to a solid.
• It changed from a solid to a liquid.

When you leave your cold drink outside, the glass may have water drops on it.  This is an example of...

• condensation
• evaporation
• precipitation
• estuary

Tags

NGSS.MS-ESS2-4

NGSS.MS-PS1-4

In the winter, some people heat their homes by burning logs in the fireplace.  How does the heat from the fire get to the other side of the room?

• it travels through the carpet by conduction
• it travels through the air by convection
• it travels through the carpet by radiation
• it travels with the smoke by condensation

Tags

NGSS.MS-PS1-4

On a cold rainy day a baby is touching a cold window.  It feels so cold. Which way is the heat moving moving? 

• Cold is moving from the window to the hand.
• Heat is moving from the hand to the window.
• Heat doesn't move.
• It moves in currents

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Heat transfer in wind.

• conduction
• convection
• radiation