Thermal Energy Q and A Review As a team you will have 60-90 seconds to discuss each question & to decide on an answer. A random team will be chosen to stand up & present their team’s answer to the class. Leaders will be the presenters SO BE READY! : P

Are you Ready Kids?

Which has more thermal energy? Which has a higher temperature? What is the difference between thermal energy and temperature? A pot of boiling water, All the oceans, or a . volcano spewing lava

The oceans have more thermal energy because if you add the kinetic movement/speed of the atoms you would have a greater number. The volcano has a higher temperature. The difference between thermal energy and temperature is that thermal is the TOTAL kinetic energy of atoms and temperature is the AVERAGE kinetic energy of the atoms.

Looking at this picture, which cube has a higher temperature? WHY? A B

Cube B has a higher Temperature because the atoms in the picture are moving faster. A B

Heat can be transferred in 3 ways Heat can be transferred in 3 ways. All 3 are shown in this picture by X, Y, & Z. Pretend the wavy lines are waves coming off of the pot. Describe how this picture is showing all 3 ways heat is transferred and SUPPORT your answer.

X is conduction because the heat element is directly touching the pot. Y is convection because as the water is being heated it rises, and when it moves away from the heat source the water cools and sinks. Z is radiation because heat is coming off the pot in waves.

Explain on a molecular level how the atoms that make up the poker are different in the end that is in the fire than the end in the man’s hand.

The atoms in the metal poker that are in the fire are moving faster (more kinetic energy) than the rest of the poker because they are exposed to more heat. Eventually, the heat will be transferred to the other end. Draw THIS diagram above

Explain why this happens. In this picture a dog is licking a popsicle. Is the heat going from the dog’s tongue to the popsicle? or Is the cold going from the popsicle to the dog’s tongue? Explain why this happens.

The heat goes from the dog’s tongue to the popsicle! WATCH =>

When watching a lava lamp we see the wax sink and float. How is the heat being transferred in this lamp and explain how this is connected to density?

The heat is being transferred through the liquid in the lava lamp by CONVECTION. As heat is being added molecules move faster and spread apart, which makes it less dense. Things that are less dense than the substance around the float. When the liquid moves away from the heat source the molecules slow down and move closer together, which makes it more dense. Things that are more dense than the substance around them sink.

These balloons shrunk down when they were put in the freezer, but when they were taken out they returned to normal size. Why did this happen?

Draw this diagram! When heat is being transferred out of an object (it’s getting colder) atoms slow down this is called THERMAL CONTRACTION

This cup of hot tea has a metal spoon in it This cup of hot tea has a metal spoon in it. The spoon is considerably hotter than the plastic cup. Why is this?

This is because the spoon is made of metal and is therefore a better conductor of heat than the plastic cup.

We have all seen glass thermometers We have all seen glass thermometers. When it gets hot the red substance goes up and when cooled it goes down. The AMOUNT of red substance stays the same so WHY does it look like it changes?

This happens because of THERMAL EXPANSION & CONTRACTION! When you heat a substance the space between the atoms expand (gets bigger) and the atoms move faster. The opposite happens when the substance gets colder.