This lightning can strike up to 10 miles away from a thunderstorm. What is sheet lightning? Sheet lightning appears as flashes of light that seem to light up or illuminate entire clouds.
What is heat lightning? Heat lightning is a term used to describe lightning flashes that are too far away from you to hear the thunder. The reason that it is called heat lightning is that it appears most often on a hot summer day when the sky is clear overhead. What is high-altitude lightning? High-altitude lightning has been given other names such as "red sprites," "green elves," and "blue jets. You can't see these types of lightning from the ground.
What is ribbon lightning? Ribbon lightning is when a bolt of lightning separates due to wind and appears as parallel lightning streaks. What is chain or bead lightning? Chain or bead lightning is when a lightning bolt is broken into dotted lines while fading. What is ball lightning? Ball lightning is a rare form of lightning. It usually appears as a reddish, luminous ball, but can come in any color. Ball lightning is usually spherical in shape and about one foot in diameter.
Hissing noises originate from such balls and they sometimes make a loud noise when they explode. What is St. Elmo's Fire? Elmo's Fire appears as a blue or greenish glow above pointed objects on the ground.
It is created when tiny positively charged sparks reach up in response to negatively charges in the air or clouds above the ground.
If a thunderstorm is nearby, St. Elmo's Fire might be seen right before a lightning strike. What is anvil lightning? Anvil lightning is a type of lightning referred to as "the bolt from the blue" because it often appears suddenly from a seemingly cloudless sky. A bolt at the top of a thunderstorm arcs away from the main cloud and strikes the ground where the skies above often appear clear. Can you tell how far away a storm is?
Yes, you can use thunder to tell how far away a storm is. Next time you see a storm, count the number of seconds between when you see the lightning and hear the thunder. Take the number of seconds and divide by 5 and that will tell you how far away the storm is in miles. For example: If you counted 10 seconds between the lightning and the thunder, the lightning is 2 miles away!
For Fluvic Endogleyic Cambisol Fig 2B and Haplic Chernozem Fig 2C the highest values of sound pressure and sound wave energy were obtained for the wettest soil pressure head 0. The values for 0. It is easy to find an explanation for this; when the soil is close to saturation at water drop hitting the surface is not able to penetrate into the deeper soil layers.
A mini-pool forms on the surface and the next water drop hits the thin water layer, not the soil. Hence, there is a noise from the splashing of water. The apparent negation of such an application is that for Endogleyic Umbrisol , the highest value of sound pressure was not for the highest water content from the fourth water drop the highest sound pressure was for 3.
As discussed in the previous sub-section, this soil had the highest content of coarse fraction sand. When the soil consists of many sand grains there are large pores between them [ 34 ]. In this case, the rate of water percolation is sufficiently high, since the large pores are not able to retain the water with capillary forces. Even when the sample is close to saturation the water flows downwards with gravity cylinders containing the samples were secured by chiffon at the bottom, which is a porous material, some of the water seeped through the chiffon and drained away.
Therefore, the sound pressure when water drop hits a surface is not connected with the water splash but rather with the deformation of soil surface. If so, it should not be expected that the sound pressure depends on the initial water content.
The variability in many cases statistically significant— S3 Table observed in Fig 2A should be attributed to the heterogeneity and the lack of reproducibility of surface micro-relief. The last observation that should be pointed out is the lack of trends in the sound pressure Fig 2 and, as a result in the energy of the sound wave between the successive water drops. In the vast majority of cases, the differences of the values between drops were not statistically significant S3 Table.
The use of measurements described in the work measurement system and testing in an anechoic chamber allowed the measurement of the sound pressure level noise and, on that basis, calculation of the resulting sound wave energy during the impact of drops on the soil surface.
It was found that the values of the sound pressure and sound wave energy were dependent on the particle size distribution of the soil, less dependent on the initial pressure head, and practically the same for subsequent water drops from the first to the tenth drop.
The sandier the soil, the higher the energy of the sound waves emitted after the water drop hit on the surface. Higher energy sound waves were also found for saturated soils. For the free impact on the soil surface of a water drop with a diameter of 4. The slightest noise impact was accompanied by drops of water on the soil surface of Fluvic Endogleyic Cambisol an average of approx. The largest was found for the Endogleyic Umbrisol soil an average of approx.
In the case of the Haplic Chernozem soil, it amounted to an average of approx. On the basis of the calculations presented in this work, it was found that the energy emitted in the form of sound waves accompanying the impact was in the range of 0.
Sound pressure level at the time of a drop of water hitting the surface of the soils studied for four different initial pressure head for: a Endogleyic Umbrisol ; b Fluvic Endogleyic Cambisol ; c Haplic Chernozem. Sound wave energy for three different soils for initial pressure head: a 0.
Letters show the determination of the significance of differences for the energy of the sound wave evoked by the impact of a given drop at different initial moisture levels.
Marks show the determination of the significance of differences for the energy of the sound wave evoked by consecutive drops at a given initial moisture level. Conceived and designed the experiments: MR AB. Wrote the paper: MR AB. Browse Subject Areas? Click through the PLOS taxonomy to find articles in your field. Abstract The splashing of water drops on a soil surface is the first step of water erosion.
Introduction Soil is a very important element and is the basis of many ecosystems; therefore, protecting it and identifying the factors causing its degradation have been a topic of scientific research for some years. Download: PPT.
Table 1. Particle size distributions of the soils used for the tests and their initial moisture content. Calculations The measured parameter was the sound pressure level mean value from eight microphones at a certain distance 1 m from the sound source.
Results Sound characteristics The signal of the instantaneous value of the sound pressure generated by water droplets striking the ground constitutes a non-stationary course of a polyharmonic, fading character Fig 1. Fig 1. Example of the timing signal for Endogleyic Umbrisol and a pressure head of 3.
Sound pressure level noise of falling drops The sound pressure levels of the accompanying the impact of the water drops on the soil surface for all the tested soils with different initial values of soil water potentials pressure heads are shown in Fig 2 and S1 Table.
Energy sound waves emitted by successive drops for different soils The energy values of the sound waves emitted during the impact of 10 consecutive droplets on the soil surface studied at different initial pressure head are shown in Fig 3 and S2 Table. Discussion The influence of the particle size distribution on sound wave energy The first aspect, that should be discussed is the comparison of the obtained results for investigated soils.
The influence of the soil initial pressure head on sound wave energy To consider the influence of the initial moisture content on the sound that result from the water drop hitting the soil, the graphs in Fig 2 should be analysed. Conclusions The use of measurements described in the work measurement system and testing in an anechoic chamber allowed the measurement of the sound pressure level noise and, on that basis, calculation of the resulting sound wave energy during the impact of drops on the soil surface.
Supporting Information. S1 Fig. Diagram showing the microphone arrangement. S1 Table. S2 Table. S3 Table. References 1. Effect of land management in mountainous regions on physical quality of sandy loam Haplic Cambisol soil. View Article Google Scholar 2.
Wysocka-Czubaszek A, Czubaszek R. Quantification of water erosion rates on the Narew River valley-sides using universal soil loss equation. Soil Sci. View Article Google Scholar 3. For example, under normal conditions the atmosphere is cooler at higher altitudes. This will result in the formation of a shadow zone, which is a region in which sound does not penetrate. In reality some sound will enter this zone due to scattering. Scattering occurs when sound waves are propagating through the atmosphere and meet a region of inhomogeneity a local variation in sound speed or air density and some of their energy is re-directed into many other directions.
In environmental noise situations, scattering is caused by air turbulence, rough surfaces, and obstacles such as trees. The scattering of sound by rain, snow or fog at ordinary frequencies is insignificant. Under conditions of a temperature inversion temperature increasing with increasing height , the sound waves will be refracted downwards, and therefore may be heard over larger distances. This frequently occurs in winter and at sundown.
For instance, the Nine O'Clock Gun in Vancouver has been heard up to 45 miles away under the proper atmospheric conditions. When a wind is blowing there will always be a wind gradient. This is due to the layer of air next to the ground being stationary. A wind gradient results in sound waves propagating upwind being 'bent' upwards and those propagating downwind being 'bent' downwards.
Temperature and wind gradients can result in measured sound levels being very different to those predicted from geometrical spreading and atmospheric absorption considerations alone. These differences may be as great as 20 dB. Louisiana State University Hearing ranges of laboratory animals. Henry E. Heffner and Rickye S. Amazing animal senses.
Eric H. Neuroscience for Kids. University of Washington. Strike a Chord - Hearing Ranges [dead link].
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