15. several days after a snowfall, the roofs of some homes on your street have almost no snow on them, while the roofs on other homes are still snow covered. assuming they have all received the same amount of sunlight, give one reason for this observation related to thermal energy and insulation?

16. if you purchased a string of lights, how could you determine if the lights were wired in series or parallel?

17. what happens to the current in a device if the resistance is decreased but the voltage stays the same?

19. explain why a magnet from your refrigerator could not be used to lift something as heavy as a car.

20. can a magnet ever have a single pole? explain your answer?

21. what happens to the wavelength of a wave if the frequency is increased?

23. as you sit outside, the sound of a siren becomes lower in pitch. is the emergency vehicle moving away from or towards you? explain how you know?

28. what is the difference in light that is refracted compared to light that is reflected? think in terms of speed of light as well as what happens to light waves when they interact with a medium?