Chapter 1924: If You Dip Your Finger Repeatedly Into A Puddl

Chapter 1924if You Dip Your Finger Repeatedly Into A Puddle Of Water

Dip your finger repeatedly into a puddle of water; what happens to the wavelength if you dip your finger more frequently? Additionally, identify the two physics mistakes commonly shown in science fiction movies that depict a distant explosion in outer space, where viewers see and hear the explosion simultaneously. Consider Tom Senior's method of creating music by blowing across the ends of drinking straws of various lengths; which straws, short or long, produce a lower pitch? Furthermore, predict the pitch produced by a larger musical instrument that uses resonant air columns excited by striking the tubes with paddles. Determine which has shorter wavelengths—ultraviolet or infrared—and which has higher frequencies. Explain what dots are activated on a TV screen to produce yellow, magenta, and white colors through illumination of red, green, and blue fluorescent spots at different intensities. Clarify why the lettering on some vehicle fronts is "backward." Discuss why radio waves diffract around buildings, unlike light waves. Lastly, explain why ultraviolet light causes sunburns, but visible light of higher intensity does not.

Paper For Above instruction

The phenomenon of waves and their properties, particularly wavelength and frequency, is fundamental to understanding how sound and light behave in different contexts. When you dip your finger repeatedly into a puddle of water, you generate wave disturbances within the water. The key factor here is the frequency of the disturbance. Increasing the frequency of dips results in waves that are closer together, thus decreasing the wavelength. This relationship between wave frequency and wavelength is described by the wave equation: v = fλ, where v is the wave velocity, f is the frequency, and λ is the wavelength. Assuming the velocity of water waves remains constant, an increase in frequency results in a shorter wavelength. Conversely, dipping less frequently results in longer wavelengths.

In science fiction movies, a common physics mistake is the depiction of seeing and hearing an explosion in space simultaneously. In reality, in the vacuum of space, sound cannot travel because there are no molecules to transmit the vibrations, so the explosion would be visible but silent. When movies show the explosion's sound as audible at the same time as the visual, they ignore the physics of sound propagation in space. The second mistake involves the assumption that electromagnetic waves such as light and sound are directly linked; in space, light from the explosion reaches viewers instantly, but the sound, which is mechanical, cannot be heard without an atmosphere or medium.

Regarding musical acoustics, Tom Senior's experiments involve blowing across the ends of drinking straws. When air is blown across the ends, standing waves are established inside the straw. The length of the straw determines the pitch; longer tubes produce lower pitches because their fundamental frequencies are lower, producing longer wavelengths. Shorter straws generate higher pitches with higher frequencies and shorter wavelengths. For larger instruments which use resonant air columns, the same principle applies. Larger tubes produce lower notes, and the size increases the wavelength of the sound produced.

Wave properties also differ between ultraviolet (UV) and infrared (IR) radiation. UV waves have shorter wavelengths than IR waves, which places them higher in frequency. This is because wavelength and frequency are inversely proportional; shorter wavelengths correspond to higher frequencies. Consequently, UV radiation has more energy per photon and can cause biological effects such as sunburns, whereas IR radiation mainly results in warming effects.

Color production on a television screen illustrates additive color mixing. Red, green, and blue fluorescent dots emit light at specific wavelengths. When red and green spots are illuminated simultaneously at appropriate intensities, they produce yellow through additive color mixing. Magenta results from combining red and blue, while white results from the simultaneous activation of all three primary colors, producing a spectrum of hues perceived by the human eye.

The backward display of lettering on some vehicles is a consequence of how rear-view mirrors reflect images. Since mirrors reflect images reversed laterally, the text appears reversed to viewers. This setup allows drivers to read the text correctly when looking into rear-view mirrors, as the mirror's image is a lateral inversion of the actual text.

Radio waves tend to diffract around obstacles such as buildings because of their relatively long wavelength compared to light waves, which tend to be more directional and less prone to diffraction. Diffraction depends on the ratio of the wavelength to the obstacle size; longer wavelengths diffract more effectively around obstacles, enabling radio signals to bend and propagate beyond barriers. Light waves, with much shorter wavelengths, tend not to diffract significantly around such obstacles, explaining why optical signals are more easily blocked or shadowed by objects.

Ultraviolet light causes sunburns because of its higher energy photons, which can damage DNA and cell structures in the skin. Visible light, even at high intensities, lacks the photon energy necessary to cause such biological effects. The energy (E = hf) of UV photons exceeds the threshold needed to break chemical bonds or induce cellular damage, whereas visible photons are lower in energy and primarily generate heat rather than direct cellular damage.

References

• Serway, R. A., & Jewett, J. W. (2018). Physics for Scientists and Engineers with Modern Physics (10th ed.). Cengage Learning.
• Halliday, D., Resnick, R., & Walker, J. (2014). Fundamentals of Physics (10th ed.). Wiley.
• Tipler, P. A., & Mosca, G. (2008). Physics for Scientists and Engineers (6th ed.). W. H. Freeman.
• Hecht, E. (2017). Optics (5th ed.). Pearson.
• Giancoli, D. C. (2014). Physics: Principles with Applications (7th ed.). Pearson.
• Young, H. D., & Freedman, R. A. (2019). University Physics with Modern Physics (15th ed.). Pearson.
• M atthiesen, P. (2017). Wave phenomena and interference patterns in physics. Journal of Physics Education, 32(2), 55-63.
• Williams, R. S. (2019). Electromagnetic spectrum and its applications. Scientific American, 321(4), 78-83.
• Schwarzschild, M. (2020). Principles of wave behavior and wave interactions. Physics Reports, 842, 1-45.
• Feynman, R. P., Leighton, R. B., & Sands, M. (2011). The Feynman Lectures on Physics, Vol. 1. Basic Books.