Sci Lab - Kinematics
Clear, plastic cup. Pour about 3 inches of water into the cup. Pour about one inch of vegetable oil into the cup. Add one drop of food coloring to the cup. You may add more salt to observe its behavior as it falls into the container. This experiment shows the density differences between salt, water, food coloring, and oil. Students will have learned that oil floats on water because it is lighter than water.
Thus, water is denser than oil. They will also learn that salt is heavier than water because as we poured the salt, it sank, taking a blob of oil, which in turn, got released once the salt was dissolved and rushed to the top again.
Questions & Answers
Miniature Lava Light. Density Experiment. Vegetable Oil. Food Coloring. What do you think will happen when we mix the oil, the salt and the food coloring with the water? Next, pour about 1 inch of vegetable oil into the cup. Then, sprinkle some salt on top of the oil while you slowly count to five. How did the oil react once it was mixed with water?
In this part the distance rolled down the ramp and the angle of slope are both variables.
Which one is on top? How did the food coloring react to the oil? How did it react to the water? Describe the order from bottom to top of the items we poured into the cup:. The pitch of a sound is determined by the frequency of vibration of the source, in other words, how many times it vibrates per second.
Pitch is an attribute of every musical tone; the fundamental, or first harmonic , of any tone is perceived as its pitch. The earliest successful attempt to standardize pitch was made in , when a commission of musicians and scientists appointed by the French government settled upon an A of cycles per second; this standard was adopted by an international conference at Vienna in In the United States, however, the prevailing standard is an A of cycles per second.
Before the middle of the 19th cent.
The relative pitch of a tone, in contrast to absolute pitch , is an expression of its pitch in relation to the pitch of some other tone taken as a standard. Pitch and Frequency : A sound wave, like any other wave, is introduced into a medium by a vibrating object. The vibrating object is the source of the disturbance which moves through the medium.
The vibrating object which creates the disturbance could be the vocal chords of a person, the vibrating string and sound board of a guitar or violin, the vibrating tines of a tuning fork, or the vibrating diaphragm of a radio speaker. Regardless of what vibrating object is creating the sound wave, the particles of the medium through which the sound moves is vibrating in a back and forth motion at a given frequency. The frequency of a wave refers to how often the particles of the medium vibrate when a wave passes through the medium.
The frequency of a wave is measured as the number of complete back-and-forth vibrations of a particle of the medium per unit of time. If a particle of air undergoes longitudinal vibrations in 2 seconds, then the frequency of the wave would be vibrations per second. A commonly used unit for frequency is the Hertz abbrviated Hz , where. As a sound wave moves through a medium, each particle of the medium vibrates at the same frequency. This is sensible since each particle vibrates due to the motion of its nearest neighbor. The first particle of the medium begins vibrating, at say Hz, and begins to set the second particle into vibrational motion at the same frequency of Hz.
The second particle begins vibrating at Hz and thus sets the third particle of the medium into vibrational motion at Hz. The process continues throughout the medium; each particle vibrates at the same frequency. And of course the frequency at which each particle vibrates is the same as the frequency of the original source of the sound wave. Subsequently, a guitar string vibrating at Hz will set the air particles in the room vibrating at the same frequency of Hz which carries a sound signal to the ear of a listener which is detected as a Hz sound wave.
The back-and-forth vibrational motion of the particles of the medium would not be the only observable phenomenon occurring at a given frequency. Since a sound wave is a pressure wave , a detector could be used to detect oscillations in pressure from a high pressure to a low pressure and back to a high pressure. As the compression high pressure and rarefaction low pressure disturbances move through the medium, they would reach the detector at a given frequency.
For example, a compression would reach the detector times per second if the frequency of the wave were Hz. Similarly, a rarefaction would reach the detector times per second if the frequency of the wave were Hz. Thus the frequency of a sound wave not only refers to the number of back-and-forth vibrations of the particles per unit of time, but also refers to the number of compression or rarefaction disturbances which pass a given point per unit of time. A detector could be used to detect the frequency of these pressure oscillations over a given period of time.
The typical output provided by such a detector is a pressure-time plot as shown below. Since a pressure-time plot shows the fluctuations in pressure over time, the period of the sound wave can be found by measuring the time between successive high pressure points corresponding to the compressions or the time between successive low pressure points corresponding to the rarefactions.
As discussed in an earlier unit , the frequency is simply the reciprocal of the period. For this reason, a sound wave with a high frequency would correspond to a pressure time plot with a small period - that is, a plot corresponding to a small amount of time between successive high pressure points. Conversely, a sound wave with a low frequency would correspond to a pressure time plot with a large period - that is, a plot corresponding to a large amount of time between successive high pressure points. The diagram below shows two pressure-time plots, one corresponding to a high frequency and the other to a low frequency.
Which one do you think produces a better pitch? Grade Level: 1 st —3 rd. Objective: Is to see if adding salt to water will melt the ice cube faster, or if would make any difference. Compare results with the rest of the groups in your class. What is your hypothesis? Record your results:. Was your hypothesis correct? Liquid Rainbow Experiment. Food coloring- 4 colors. Transparent drinking straws. Pickling or Kosher salt.
The purpose of this experiment is to challenge students to layer five liquids of different density in a drinking straw. They will learn how to observe and interpret data as well as learn the basic concept of density. Preparation: Prepare five salt solutions, each with a different density. Mix the solutions thoroughly, until all salt is dissolved.go here
Forces and motion
Pickling salt is preferred for this activity because it does not have any additives and will not make cloudy solutions, but regular salt can be substituted. Add the entire contents of one of the small bottles of food coloring, usually sold in sets of four at the grocery store. Clear or translucent drinking straws must be used so that the colors of the different solutions can be observed when in the straw.
Each student or group of students will need six small containers; five to hold the solutions and one to be used as a waste container. Presentation: Do not allow students to see how much salt is in the solutions. Place the five pitchers in a random order. Distribute a sample of each of the five solutions to students.
Allow them to practice placing a finger over the end of a straw and "picking up" a sample of a solution. Direct them to select two of the solutions at random.
Draw a small portion of the first solution into the straw. While holding the solution in the straw, lower the end of the straw into the second liquid. Draw a sample of the second solution into the straw. If the first solution floats on the second, the first is less dense.
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