#### Study Guide Review

What happens to thermal energy as you increase the temperature of an object?

The thermal energy increases

What happens to thermal energy when the temperature decreases?

Thermal energy decreases

What happens to thermal when the mass increases?

Thermal energy increases

What about the kinetic energy when you increase the temperature of an object?

It increases too

What happens to the kinetic energy when the temperature decreases?

It decreases too

On a hot day, what happens to the kinetic energy of air molecules? Describe their motion as well.

It increases, The molecules move faster.

What is an independent variable?

The variable that is changed by scientists in an experiment.

What is a dependent variable?

The effect of the independent variable. What you are measuring in the experiment.

What is a constant (control variable)?

What you keep the same in each trial of an experiment.

You want to figure out which brand of microwave popcorn pops the most kernels so you can get the most value for your money. You test different brands of popcorn to see which bag pops the most popcorn kernels.
What is the independent variable?
Brand of mic

When we designed our dog crates what were some problems that you ran into? How could you fix these problems?

Temperature not lowering enough. To fix we designed and made modifications.

When we do iterative testing, why do we only change one element of our designs at a time?

Only change one at a time, so you know what effect that variable had on the experiment. If you change multiple you have no idea what variable actually affected the experiment.

Why is it important to do many trials during the testing of a solution?

Need to have at least 3 trails to show a pattern. You need to show that it happens over and over again to make it true.

Think about our heated bolts lab. We added 2 hot bolts and then added 4 hot bolts, then we added 6. This added different masses to the water and oil. Which one showed the greatest change in temperature? Why?

When we added 6 bolts because the mass was greater. The greater the mass the greater the temperature change.

Thermal Energy transfers from _______________ temperatures to ____________ temperatures.

Hot (higher) and Cold (lower)

What has to happen in order for molecules to transfer thermal energy?

They have to collide with one another.

If you have two cups with the same amount of water sitting in a 25 degree Celsius room. Cup A water temperature is 60 degrees Celsius and Cup B has a water temperature of 5 degrees Celsius.

Which cup has the highest kinetic energy? How do you know
Cup A because it has the highest temperature. The higher the temp the faster the molecules move and the higher the kinetic energy.
The water temperature in cup B will increase/decrease/stay the sam

How can you maximize thermal energy transfer between a cup and air in a room? (Think about your dog crates and how you maximized the thermal energy transfer)

Add a wet paper towel to the cup.
Explain how this method works.
The thermal energy is transferred from the cup to the wet paper towel. The water in the paper towel absorbs the energy. It then evaporates. This transfer of thermal energy causes the tempera

What does the total amount of thermal energy in a system depend on? (3 things!)

The temperature and mass of the objects and surroundings.

If you leave a hot saucepan on a stove that has been turned off. Eventually, over time, the pan, the stove and the air will all be the same temperature. Why is this?

They will reach equilibrium. The amount of energy coming in and going out are eventually equal to one another.

You have two pencils, they have the same type of molecules and the same number of molecules. However, pencil 1 has more thermal energy than pencil 2.

Is the average speed of the molecules in pencil 1 more, less, or the same as pencil 2?
Pencil 1 has faster molecule because it has more thermal energy which means more kinetic energy. So they must be moving faster, if they have the same number of molecule

What is a system boundary?

The barrier between the system and the outside. Ex.: In the can experiment the boundary was the can wall.

What are inputs to a system?

The energy that comes into the system.

What are outputs to a system?

The energy that comes out of the system.

In a closed system, there is no thermal energy entering or leaving. What happens to the temperature?

The temperature will stay the same.

What do we call a system that is in balance? It has an equal exchange of energy? (vocabulary word)

Equilibrium

You have a bunch of ice cubes and some hot water. What do the molecules look like in the ice cubes and in the water? Draw them. Be sure to use a key!!

The ice molecules are close together and just vibrating in place. The water molecules are more spread out and moving fast. Show this by drawing the molecules and then adding medium sized arrows.
You add the ice to the water and let the cup sit for 5 minut