Grade 7 Physical Pretest

Transcription

1 Grade 7 Physical Pretest Select the best answer to each question. 1. Energy from the sun arrives as electromagnetic radiation with a wide range of wavelengths and frequencies. Of the four wave types listed, which has the lowest frequency? A. x-ray waves B. infrared waves C. ultraviolet waves D. visible light waves 2. The diagram below represents waves from the electromagnetic spectrum. Assume that the diagram above shows infrared radiation. How would a diagram showing X-rays be different? A. The distance indicated by D would be longer. B. The distance indicated by C would be shorter. C. The point represented by A would not be present. D. The point represented by B would be at the top of each wave. 3. Infrared and ultraviolet light are both part of the electromagnetic spectrum. How is infrared light different from ultraviolet light? A. Only ultraviolet light comes from the Sun. B. Only ultraviolet light travels at the speed of light. C. Infrared light has a higher frequency than ultraviolet light. D. Infrared light has longer wavelengths than ultraviolet light. 4. Red light waves and yellow light waves travel through air and strike the surface of glass. Only the yellow light waves travel through the glass as shown in the figure below.

2 Which of these phrases best describes what the glass does? A. reflects red light B. absorbs yellow light C. transmits red light D. transmits yellow light 5. As Miguel walked farther from the soccer field after the evening game, the lights from the field got dimmer. What causes a beam of light to get dimmer the farther it travels through the air? A. absorption B. reflection C. refraction D. scattering 6. Tyler observed that light can be reflected, absorbed, and refracted. What causes the refraction of light? A. Light waves travel extremely fast. B. Light waves move at different speeds through different materials. C. Light waves can have different wavelengths and different frequencies. D. Light waves maintain the same speed as they travel through a different material. 7. In which of these situations would light slow down? A. from glass to air B. from ice to water C. from plastic to air D. from a vacuum to air 8. The pitch of a sound wave depends on its frequency. A high frequency results in a high pitch, while a low frequency results in a low pitch. The diagram below shows the frequency of a sound wave.

3 How should this diagram be changed to show that the wave has a higher pitch? A. Eliminate half the dots in the diagram. B. Move the areas labeled N and M closer to each other. C. Make the entire diagram look like the areas labeled N and M. D. Move the areas labeled N and M farther apart from each other. 9. Kalinda hates the sound of her alarm clock in the morning. What would be the best way for Kalinda not to hear the sound even if the alarm clock is ringing? A. Put the alarm clock in a jar, and put it in her closet. B. Put the alarm clock in a jar, fill it with cotton, and seal it. C. Put the alarm clock in a jar, remove all the air from it, and seal it. D. Put the alarm clock in a sealed jar and cover it with a hand towel. 10. As part of a lab experiment, Tasha drops a metal cube into a beaker of water, as shown in the figure below. After energy in the form of heat transfers between the substances, what is the final temperature of the water? A. The final temperature is 25 C because there is more water than metal. B. The final temperature is 50 C because the metal warms the water to the temperature of the metal. C. The final temperature is between 25 C and 50 C because energy is transferred from the metal to the water. D. The final temperature is between 25 C and 50 C because most of the thermal energy is lost to the air around the substances. 11. The water in Mario s swimming pool absorbs energy as heat during the day. Which of the following would the water in the pool be most likely to do? A. condense B. evaporate C. freeze D. melt

4 12. During the summer, Chang takes a glass of milk from the refrigerator and places it on the kitchen counter. Over time, energy as heat is transferred to the milk from the air. Which change would most likely occur? A. The temperature of the milk will increase. B. The temperature of the milk will decrease. C. The milk will change from a liquid to a gas. D. The milk will change from a liquid to a solid. 13. Ms. Lewis is a chemist mixing two solutions together. A chemical reaction takes place, and the solution becomes warm. Which statement best describes what has happened? A. Energy has been created in the form of thermal energy. B. Energy has been transformed from one form to another. C. More energy has been created than has been destroyed. D. The chemical energy of the solution has been destroyed. 14. During a science experiment, students compress four springs and then release them. In which position would the greatest conversion of elastic energy to kinetic energy occur when the spring is released? A. Position 1 B. Position 2 C. Position 3 D. Position Caleb builds a birdhouse. When he hits a nail with a hammer, the kinetic energy of the hammer transfers to the nail. Which energy conversion also occurs at the point that the hammer hits the nail? A. elastic energy to light energy B. kinetic energy to sound energy C. sound energy to thermal energy D. kinetic energy to electrical energy 16. Which happens when energy is transferred from one system to another? A. New energy is created. B. Some energy is destroyed.

5 C. The energy changes forms. D. The energy changes into mass. 17. When Meagan strikes her drum, the skin of the drum moves. The kinetic energy of the skin is converted to sound energy. Which statement best explains why all of the kinetic energy is NOT converted to sound energy? A. Some of the kinetic energy is lost as heat. B. The skin of the drum absorbs kinetic energy. C. Friction slows the movement of the drum skin. D. The kinetic energy is converted to potential energy. 18. Caroline dives from a diving board. Which statement best describes the energy conversion that occurs from the moment she dives to the moment she hits the water? A. Energy is gained as she moves upward and then lost she moves downward. B. Energy is lost as she moves upward and then gained as she moves downward. C. Kinetic energy is gained as she moves upward and then lost as she moves downward. D. Potential energy is gained as she moves upward and then lost as she moves downward. 19. Emerson places a beaker of water on a hotplate and turns the hotplate on. The temperature in the room is 25 ºC. After the water heats to 75 ºC, she adds pieces of ice to the beaker.

6 Which of the following describes a transfer of heat energy that occurs during this experiment? A. from the air to the water B. from the ice to the beaker C. from the water to the ice D. from the water to the hotplate 20. Joe places two solid objects in contact with each other. Which property determines the direction of the flow of heat between the two objects? A. material of the objects B. volume of the objects C. density of the objects D. temperature of the objects 21. Jeriah places two metal cubes in contact with each other. Energy as heat flows from Cube A to Cube B. What conclusion can you draw regarding Cube A? A. It is larger than Cube B. B. It is cooler than Cube B. C. It is smaller than Cube B. D. It is warmer than Cube B.

7 Grade 7 Physical Pretest Answer Section MULTIPLE CHOICE 1. ANS: B A is incorrect because infrared waves have a lower frequency than x-ray waves. B is correct because infrared waves have the lowest frequency of the four wave types listed. C is incorrect because infrared waves have a lower frequency than ultraviolet waves. D is incorrect because infrared waves have a lower frequency than visible light waves. STA: SC.7.P ANS: B A is incorrect because the distance indicated by D would be shorter because X-rays have a higher frequency. B is correct because X-rays have a higher frequency than infrared waves. C is incorrect because both infrared waves and X-rays have amplitude, which is indicated by A. D is incorrect because the waves of both infrared radiation and X-rays have a trough, which is represented by point B. STA: SC.7.P ANS: D A is incorrect because all electromagnetic waves come from the Sun. B is incorrect because all electromagnetic waves travel at the speed of light in a vacuum. C is incorrect because ultraviolet light has shorter wavelengths and therefore a higher frequency than infrared light. D is correct because ultraviolet light has shorter wavelengths. STA: SC.7.P ANS: D A is incorrect because no light waves reflect off the glass surface. B is incorrect because yellow light travels through the glass. C is incorrect because no red light passes through the glass. D is correct because the yellow light travels through the glass. STA: SC.7.P ANS: A A is correct because the particles in the air absorb some of the energy from the light, causing the light to get dimmer. B is incorrect because reflection would cause light to bounce off the particles and reflect back toward the direction from which the beam came. C is incorrect because refraction of light occurs when light passes between two substances in which the speed of the wave differs. D is incorrect because the scattering of light by particles in the air would cause the beam to change direction. STA: SC.7.P ANS: B A is incorrect because refraction is caused by a change in the speed of light as it passes into a second material. B is correct because light waves will change direction as their speed changes.

8 C is incorrect because, although light does vary in wavelength and frequency, changes in wavelengths and frequencies do not cause changes in direction. D is incorrect because light waves change speed when they move through a different material. STA: SC.7.P ANS: D A is incorrect because light would speed up while going from a solid to a gas. B is incorrect because light would speed up while going from a solid to a liquid. C is incorrect because light would speed up while going from a solid to a gas. D is correct because light slows down while going from a vacuum to any type of matter. STA: SC.7.P ANS: B A is incorrect because reducing the number of dots would not indicate a change in frequency. B is correct because moving them closer together would illustrate a higher frequency and therefore a higher pitch. C is incorrect because this would indicate a lower frequency and therefore a lower pitch. D is incorrect because the frequency would be shown as having decreased, resulting in a lower pitch. STA: SC.7.P ANS: C A is incorrect because although the alarm might sound muffled, the sound will still travel through the jar and the door of the closet. B is incorrect because the alarm could still travel through the cotton and jar. C is correct because sound waves cannot travel through a vacuum. D is incorrect because sound waves can still travel through the jar and towel. STA: SC.7.P ANS: C A is incorrect because energy is transferred from the metal to the water, so the metal becomes cooler and the water becomes warmer. B is incorrect because energy is transferred from the metal to the water, so the metal becomes cooler and the water becomes warmer. C is correct because heat is the transfer of energy from an object with higher temperature to an object with lower temperature. When the objects reach the same temperature, the final temperature of the water is between the two original temperatures. D is incorrect because most of the energy transfer is between the two substances. This causes the metal to lose energy and the water to gain energy. STA: SC.7.P ANS: B A is incorrect because water can condense when energy as heat is removed, not added. B is correct because if enough energy as heat is added to the system, liquid water can change to gaseous water. This change of state from a liquid to a gas is called evaporation. C is incorrect because water can freeze when energy heat is removed, not added. D is incorrect because melting is a change from a solid state to a liquid state. STA: SC.7.P ANS: A A is correct because the transfer of energy as heat over time will cause the temperature of the milk to increase.

9 B is incorrect because the transfer of energy as heat will cause the temperature of the milk to increase, not decrease. C is incorrect because this change would occur only if there was a large transfer of energy as heat, which is not provided by the air. D is incorrect because a change from a liquid to a solid occurs when heat is removed, not added. STA: SC.7.P ANS: B A is incorrect because the law of conservation of energy states that energy cannot be created but can only change in form. B is correct because the law of conservation of energy states that energy cannot be created or destroyed but can only change in form. C is incorrect because the law of conservation of energy states that energy cannot be created or destroyed but can only change in form. D is incorrect because the law of conservation of energy states that energy cannot be destroyed but can only change in form. STA: SC.7.P.11.3 SC.7.P ANS: D A is incorrect because Position 4 shows greater compression than Position 1. The spring with the greatest compression will have the greatest elastic energy. B is incorrect because in Position 2, the spring is least compressed, giving it the lowest elastic energy. C is incorrect because Position 4 shows greater compression than Position 3. The spring with the greatest compression will have the greatest elastic energy. D is correct because the spring has the greatest elastic energy when it is compressed the most. STA: SC.7.P ANS: B A is incorrect because light energy may be produced if there is a spark, but this result would not involve a conversion from elastic energy to light energy. B is correct because a hammer hitting a nail makes a sound. This result occurs because kinetic energy is converted to sound energy. C is incorrect because although sound and thermal energy would both be produced, they are the result of kinetic energy converting to sound energy and thermal energy. D is incorrect because kinetic energy is converted to other types of energy, but not to electrical energy. STA: SC.7.P ANS: C A is incorrect because energy is conserved when it is transferred from one system to another. B is incorrect because energy is conserved when it is transferred from one system to another. C is correct because the law of conservation of energy states that energy cannot be created or destroyed but can only change in form when it is transferred from one system to another. D is incorrect because energy can change into mass only during nuclear reactions, not when it is transferred between systems. STA: SC.7.P ANS: A A is correct because during the energy conversion from kinetic energy to sound energy, some of the energy is converted to thermal energy and lost as heat. B is incorrect because kinetic energy is converted to other forms of energy, not absorbed.

10 C is incorrect because although friction does slow the movement of the drum skin, this does not explain the energy conversions. D is incorrect because the kinetic energy is converted to sound energy and heat energy, not potential energy. STA: SC.7.P ANS: D A is incorrect because energy is converted from one form to another, but is not gained or lost. B is incorrect because energy is converted from one form to another, but is not gained or lost. C is incorrect because kinetic energy is lost as Caroline moves upward and then gained as she moves downward. D is correct because the potential energy increases as Caroline s height above the water surface increases from 10 meters to 12 meters. The potential energy decreases as she moves from 12 meters to the surface of the water. STA: SC.7.P ANS: C A is incorrect because energy would be transferred from the warmer water to the colder air. B is incorrect because energy would be transferred from the warmer water to the colder ice. C is correct because the water would be warmer than the ice. Energy would be transferred from the warmer water to the colder ice. D is incorrect because energy would be transferred from the warmer hotplate to the colder water. STA: SC.7.P ANS: D A is incorrect because the direction of heat flow depends on the relative temperatures of the objects, not their materials. B is incorrect because the direction of heat flow depends on the relative temperatures of the objects, not their volumes. C is incorrect because the direction of heat flow depends on the relative temperatures of the objects, not their densities. D is correct the direction of heat flow depends on the relative temperatures of the objects. Heat flows from the warmer object to the cooler object. STA: SC.7.P ANS: D A is incorrect because the direction of heat flow does not depend on the relative sizes of the cubes. B is incorrect because energy as heat would flow from Cube B to Cube A if Cube A is cooler than Cube B. C is incorrect because the direction of heat flow does not depend on the relative sizes of the cubes. D is correct because energy as heat flows from warmer objects to cooler objects. If heat flows from Cube A to Cube B, then Cube A must be warmer than Cube B. STA: SC.7.P.11.4