Strand I: Energy Transformations

CAPT SCIENCE REVIEW: Strand I: Energy Transformations Essential Question: What is the role of energy in our world?

Multiple Choice Questions

Recreation Center Pool A local recreation center has received funding to build a swimming pool. After construction, the center will be responsible for all costs associated with pool operation. As a result, the center must consider a variety of design options, including pool size, location and heating.

_____1. What happens to water molecules in a pool as they absorb energy? ( D.1)

A. The molecules occupy less volume. B. The molecules begin to move more slowly. C. The kinetic energy of the atoms decreases. D. The rate of collisions between molecules increases.

_____2. Prior to pool construction, engineers use computer models to compare which of several pool designs require the least amount of energy to be heated. What is the dependent variable in the computer models? (DINQ. 5)

A. Pool size B. Pool shape C. Pool location D. Pool temperature

_____3. Where should hot water enter the pool to better heat the water? ( D.2)

A. A B. B C. C D. D

1 _____4. Windmills are used to convert wind energy into a more useful form. In most cases, there are three steps in this process. The energy is in a different form at each step. Which of the following flow charts shows the most likely order of the energy changes? ( D.3.)

A. Wind energy →mechanical energy → solar energy B. Wind energy → thermal energy → mechanical energy C. Wind energy → solar energy → electrical energy D. Wind energy → mechanical energy →electrical energy

______5. To demonstrate static electricity, a teacher takes an inflated rubber balloon and rubs it on his head. The rubber balloon picks up electrons from his hair, which causes his hair to have a(n)……(D.4)

A. Electrical current. B. Net positive charge. C. Net negative charge. D. Buildup of magnetic energy.

In the Kitchen Common kitchen appliances include electric stoves, toasters and blenders. Each appliance uses an energy source and involves energy change to prepare food.

______6. An open pot of water is heated on the stove. As water boils, the molecules ______. (D.1) A. Move slower and closer together. B. Move faster and farther apart. C. Get larger. D. Get smaller.

______7. When in use, the heating element in a toaster glows and gives off heat. This is because atoms within the heating element ______. (D.5)

A. Undergo chemical reactions. B. Are excited by the flow of electrons. C. Gain electrons and increase in temperature. D. Conduct light and heat from the outlet.

2 In the Kitchen (continued)

A group of students carried out the following investigation.

“Our hypothesis is that the greater the wire diameter used in a toaster, the greater the resistance in the wire.”

1. We took a 4-meter length of wire with a diameter of 0.5 millimeters. 2. We attached the wire to a 3-volt battery and measured the current. 3. Knowing the voltage and current, we calculated the resistance in the wire. 4. We repeated the same steps with wires of increased diameter. 5. We organized our data in the table below.

Diameter of Wire Measured Current Calculated Resistance (millimeters) (milliamps) (ohms) 0.5 10 300.0 1.0 40 75.0 1.5 80 37.5 2.0 100 30.0 2.5 250 12.0

______8. To be certain that data in the table are correct, you will have to ______. (D.INQ.7)

A. Go online and seek additional information. B. Ask for your teacher’s opinion. C. Repeat the experiment as described. D. Repeat the experiment with different variables.

_____9. When a bar magnet is cut in half it will (D.6)

A. Lose all its magnetism. B. Lose the magnetism in one half but not the other. C. Become two smaller magnets. D. Produce separate north and south magnets.

_____10. A power company is building a new power plant to provide electricity for several communities. What is a major advantage of using wind energy instead of coal or nuclear power plants? (D.9)

A. Wind is a renewable energy source. B. Wind is consistently available in all locations. C. Windmills reduce the strength of severe storms. D. A single windmill produces more energy than a nuclear power plant.

3 The picture below shows a turbine generator used to produce electricity at a geothermal power plant.

______11. Electricity is produced by using steam to ______. (D.7)

A. Heat the turbine generators B. Spin the turbine generators C. Reduce the friction in the turbine generators D. Reduce the emissions from the turbine generators.

_____12. A log was burned in a fireplace. Which statement is true about the leftover ashes when they are compared to the original unburned log? (D.3)

A. The ashes have more mechanical energy than the unburned log. B. The ashes occupy the same amount of space as the unburned log. C. The ashes have less chemical energy than the unburned log. D. The ashes have the same molecular structure as the unburned log.

_____13. The bulbs in a set of holiday lights are arranged in a series circuit. You remove one bulb from the middle of the string. What result would you expect? (D.4)

A. The other bulbs will continue to light up when plugged in. B. The other bulbs will not light up when plugged in. C. The two bulbs on either side of the bulb will not light up, but the others will. D. Half of the bulbs will light up.

4 Strand I: Open-Ended Questions

Solar Cooker Investigation A student hypothesized that container size will affect the performance of solar cookers in heating water. The student wrote and performed the following procedure to support her claim.

PROCEDURE: 1. Line three identical cardboard boxes with aluminum foil to use as solar cookers. 2. Place the solar cookers outside in direct sunlight. 3. Place a large glass container of water in the center of the first box. 4. Record the initial temperature of the water. 5. Allow the container to sit in the sun for 2 hours, and then check and record the final temperature of the water. 6. Place a medium-sized glass container of water in the center of the second box. 7. Repeat steps 4 and 5. 8. Place a small-sized glass container of water in the center of the last box. 9. Repeat steps 4 and 5.

The chart below shows the student’s data.

Solar Cooker Data Container Temperature (oC) Initial Final Large 39 48 Medium 39 49 Small 39 49

1. Draw a conclusion regarding container size and the effectiveness of solar cookers in heating water, based on the student’s results.

2. Describe two ways the student could have improved her experimental design and/or the validity of her results.

5 Strand I: Open-Ended Questions (continued)

Energy Consumption The graph below shows the energy consumption for coal and natural gas in Connecticut for 40 years.

1. Describe the overall trend for coal or natural gas from 1960-2000.

2. Make a prediction regarding the energy consumption of coal or natural gas for the year 2015.

3. Support your prediction with specific information from the graph.