Energy Conversion System Gizmos

Kennedy High School (California) - La Palma

Recommended for you

and Solubility KEY" width="115px" />

Comments

Students also viewed

Related documents

Preview text

Student Exploration: Energy Conversion in a System

Directions: Follow the instructions to go through the simulation. Respond to the questions and prompts in the orange boxes.

Vocabulary: energy, gravitational potential energy, heat energy, kinetic energy, law of conservation of energy, specific heat capacity

Prior Knowledge Questions (Do these BEFORE using the Gizmo.) A battery contains stored energy in the form of chemical energy.

1. What are some examples of devices that are powered by batteries?

Some examples include phones, remote controls, and flashlights.

1. What different forms of energy are demonstrated by these devices?

Most of these devices demonstrate kinetic and electrical energy

Gizmo Warm-up Energy constantly changes from one form to another, but in a closed system, the total amount of energy always remains the same. This concept is known formally as the law of conservation of energy.

TheEnergy Conversion in a System Gizmo allows you to observe the law of conservation of energy in action. In the Gizmo, a suspended cylinder has gravitational potential energy. When the cylinder is released, the gravitational potential energy is converted into kinetic energy, which causes the stirrer in the water to spin.

1. What is the initial temperature ( T) of the water? 25 degrees Celsius
2. Click Play ( ). What happens as the cylinder drops?

The temp increases, while the cylinder’s height decreases.

1. What is the final temperature of the water? 29 degrees Celsius
2. Why do you think the temperature of the water increased?

I think that the temp increased due to heat energy as it turned the liquid into gas

Potential energy and height

Get the Gizmo ready: ● Click Reset ( ).

Introduction: The raised cylinder in the Gizmo has gravitational potential energy (GPE) because gravity can cause the cylinder to drop. When the cylinder drops, its kinetic energy is converted into heat energy, which raises the temperature of the water.

Question: How does the cylinder’s initial height affect its gravitational potential energy?

1. Predict: How do you think increasing the cylinder’s height will affect the final temperature of the water?

The higher the cylinder is positioned the more heat it would create

1. Gather data: Make sure the water’s Mass is 1 kg, its Temp is 25 °C, and the cylinder’s Mass is 5 kg. Set the cylinder’s Height to 100 m. (Note: The large height scale used by the Gizmo, while not practical in a real-world experiment, makes it easier to produce observable temperature changes in the water.)

Click Play, and record the water’s final temperature in the table below. Repeat the experiment at each cylinder height to complete the second column in the table.

Cylinder height (m) Final temp. (°C) Change in temp. (°C) CylinderGPE (J) 100 m 26 C 1 C 4900 J 200 m 27 C 2 C 9800 J 500 m 30 C 5 C 24500 J 1,000 m 36 C 11 C 49000 J

1. Calculate: Subtract the water’s initial temperature from its final temperature to complete the third column of the table.

An object’sGPE can be calculated by multiplying its height (h) by its mass (m) and acceleration due to gravity (g): GPE =mgh. On Earth,g = 9 m/s 2. Calculate the cylinder’sGPE for each of the trials you completed and fill in the last column of the table.

1. Analyze: Study the data you collected.

A. How does doubling the height of the cylinder affect itsGPE?

It will increase the number of joules being produced.

B. How does doubling the cylinder’sGPE affect the change in temperature experienced by the water?

It affects the change in temp. by doubling it.

Heat energy and temperature

Get the Gizmo ready: ● Click Reset. ● Select the GRAPH tab and choose the Generated heat option.

Question: What factors affect how much the water’s temperature changes when a given amount of heat energy is added to the water?

1. Form hypotheses: In activity A, you discovered how changing the cylinder’sGPE affects the water’s final temperature. Now consider the following questions:

A. How will changing the water’s initial temperature affect how much the water’s temperature increases when the cylinder is dropped?

The cylinder after the temperature drops

B. How will changing the water’s mass affect how much the water’s temperature increases when the cylinder is dropped?

The temperature will decrease

1. Gather data: Set the cylinder’s Mass to 5 kg and its Height to 500 m. Use the Gizmo to test each of the scenarios listed in the table and record your results in the last three columns. Use the graph to estimate the generated heat.

Water’s initial temp. (°C)

Water’s final temp. (°C)

Change in temp. (°C)

Generated heat (kJ) 1 kg 0 °C 5 5 5. 1 kg 20 °C 25 5 5. 1 kg 40 °C 45 5 5. 0 kg 25 °C 36 11 11. 1 kg 25 °C 30 5 5. 1 kg 25 °C 28 3 3.

1. Explain: Why was the amount of heat generated the same each time?

The pattern that was followed caused the amount generated to be the same each time.

1. Analyze: Use the data you collected to answer the following questions.

A. What was the effect of the initial temperature on the temperature change of the water, and why do you think this happened?

The initial temp determined the final temp along with the mass of the water.

B. What was the effect of doubling the water mass on the temperature change, and why do you think this happened?

The final temp decrease because it got colder

1. Challenge: Not all substances heat up and cool down at the same rate. A substance’s resistance to temperature change is described by its specific heat capacity, or specific heat for short. For example, the specific heat of iron is 0 J/g °C. That means it takes 0 joules of heat energy to increase the temperature of a gram of iron by one degree Celsius.

Specific heat capacity can be calculated using the following equation:q =mc∆T.

In the equation,q represents the amount of heat energy gained or lost (in joules),m is the mass of the substance (in grams),c is the specific heat capacity of the substance (in J/g °C), and ∆T is the temperature change of the substance (in °C).

Click Reset. Set the water Mass to 1 kg (1,000 g). The cylinder should have a Mass of 5 kg and a Height of 500 m.

A. What is the gravitational potential energy of the cylinder? 5kg

B. If no energy is lost, how much heat energy is added to the water? 45 C

C. What is the mass of the water? 1kg

D. What is the temperature change of the water? 5 C

E. What is the specific heat of the water? (Show your work below.) 4/g

c = 24500 j / 1000 x 5 c = 4/g

F. How does the specific heat of water compare to the specific heat of iron?

The specific heat of water compares to the specific heat of iron because they both depend on the mass and temp.