Hobbies And Interests
The Temperature-Pressure Relationship
From understanding combustion engines to predicting whether patterns, the direct relationship between temperature and pressure is a fundamental property of gases encountered in everyday life. A simple way to demonstrate this with a hands-on science project requires a two-liter soda bottle, inflatable balloons and two bowls of hot and cold water. First cover the opening of the soda bottle with a deflated balloon; the air inside the bottle will be at room temperature at this point of the experiment. Next, submerge as much of the bottle as possible in the bowl of hot water; observe the change in air pressure as the balloon begins to inflate. Pressure in a closed space is related to the kinetic energy of air molecules; as the temperature of the air increases, the molecules will bounce around the bottle with greater energy, thus increasing the pressure within the balloon. Next, move the bottle to the cold bowl of water, which will immediately cause the balloon to deflate as the air temperature cools and the pressure within the bottle drops. If the water is cold enough, the balloon may actually invert itself as it is sucked into the bottle due to the low pressure.
Dissecting Light
White light is composed of all colors of the visible light spectrum. Rainbows form when white light rays from the sun pass through water vapor in the air, which breaks the light into its component wavelengths of electromagnetic energy. With a glass prism or a spectroscope, light can similarly be dissected into its component wavelengths of color, through a process known as refraction, for observation in a science project. Electromagnetic radiation is ubiquitous, most obviously present in your everyday life in the form of visible light. Explain to the students that all the colors they see throughout the day are composed of this electromagnetic energy; prisms and spectroscopes can be used observe this property of light first hand. As additional activity, use color filters to restrict the passage of light through the prism or spectroscope; for instance, a purple filter will only allow blue light to enter the prism, thus only blue and red light will emerge after the light has been refracted.
3D Illusions
For a fun science project exploring how binocular vision allows humans to see the world in three dimensions, give the students a piece of paper, a set of 3D glasses, and a pair of pink and blue fluorescent markers. Instruct the students to draw a simple image with the blue marker that can be easily replicated, such as a stick figure or a square. Then have the students draw the same image on top of the original figure, just slightly shifted so the two are not directly superimposed; refer to the resource section for examples of how this should be done. Encourage the students to experiment with their drawings and they will begin to see how their pictures appear to jump off the page because of the color filtering effect. Explain to the students that two-dimensional images, such as pictures on paper, normally do not have a third dimension because both your eyes are seeing the exact same image. Depth can only be perceived when your brain receives two images of the same object from slightly different angles, which is normally only possible when the object actually has three dimensions. 3D glasses produce this effect artificially by filtering out the blue colors in one eye (the blue filter) and the red colors in the other (the red filter). This creates two slightly shifted images of the same object; your brain then takes that information and interprets it as a three-dimensional object, despite the fact that it is drawn on a flat screen or piece of paper. This trick of the eyes and mind explains a lot about how binocular vision allows humans to see two slightly different images and combine them into a final 3D product in the brain.
The Relativity of Temperature
The importance of using measuring equipment in everyday life can be appreciated when considering how humans perceive temperature on a "relative" scale. For example, jumping into a pool after sitting in a hot tub for an extended period is a shocking experience. Your brain will focus on the temperature change in this situation, rather than the absolute temperature of either environment. A science project to demonstrate this phenomenon in the classroom requires three bowls and access to hot and cold water. Arrange the bowls in a row, with the first and last filled with hot and cold water, respectively. Next, mix some of the hot and cold water together in the middle bowl to create a lukewarm solution; the three bowls should hold approximately the same amount of water at this point. Invite two volunteers from the class to participate in the experiment. Instruct the first student to submerge her hand in the hot water and the second in cold water for approximately 20 seconds. Finally, tell the students to simultaneously move their hands from the hot or cold water to the middle, room temperature bowl and ask them each to describe the temperature of this water. The students will invariably give different answers, despite the fact that they are clearly talking about the same bowl of water. The student that started in the hot water will describe the middle bowl as ice cold, while the other student will perceive the same water as hot to the touch. Explain that neither of the students are incorrect in their perception; the relativity of temperature results in very different experiences depending on the water temperature the student adjusted to in the beginning of the experiment. Also point out that the relativity of temperature is experienced on a daily basis as you move between different environments with variable temperatures.