Three Science Experiments You Can Do With Your Phone
Reyes Grindberg
Engineers systematically analyze materials and processes in order to create things for the benefit of humanity and our world. Communications engineers are particularly focused on sound and creating technology to transmit sound long distances with little loss in clarity.
Have you ever noticed that you can hear sounds through solids? Everyone put your ear to you desk and scratch the surface with your fingernail. Now sit up and again scratch the desk surface. Is there a difference? (Have a few students comment, one at a time. Make sure they recognize that the sounds are louder with their ears to the desks.)
If you can hear a sound through your desk, does that mean your desk is moving? Take one minute to discuss with the people around you what is happening. (The answer is yes, tiny parts of the desk are moving with the sound wave. Refer to the slinky example in the associated lesson if more explanation is required.)
So when sound travels through a solid, it travels the same way as it does through air: in a sound wave. The sound wave actually moves the tiny particles, or molecules, that make up the solid. We now know from experience that these sound waves sound louder when we hear them through solids. If you wanted to say something to your friend on the other side of the playground, would your friend be better able to hear you through the air or through a solid? (Poll students.)
One reason engineers learn about sound waves is to design things that help people talk to each other over long distances, like the telephone, cell phone, or the internet. Engineers are helping bring the world closer together by developing technologies that enable long-distance communication. Today we are going to learn more about how sound travels using a paper cup and string. We are going to model a simple string guitar, analyze how sound moves through our model, and think about how the model relates to a telephone. Then we are going to combine our models with a partner's to make string telephones for two-way communication.
Iterate the Designs: Have students think about modifying their final string telephone designs even more. What would they do to further improve their designs? Would they change the materials for the cups or string? What might they use? Have students think about other features on telephones. What special features would they want to include on their string telephones? Give students time to draw or describe their new design ideas.
The string pulls out of the hole in the paper cups if students pull too hard. If this happens attach the string to a small paper clip to anchor it in the cup. This does not affect the sound performance.
Have students compare the loudness of sound with the distance of the cups. Give them a longer length of string with which to test, and have them decrease the length of string by half each time to see if distance affects the sound. They should notice a difference, since sound waves lose strength with distance (as learned in the associated lesson). Explain to students that engineers have helped sound travel great distances by designing devices that convert the sound waves into electricity and back.
Students are introduced to communications engineers as people who enable long-range communication. In a demonstration, students discuss the tendency of sound to diminish with distance and model this phenomenon using a slinky.
Students are introduced to sound energy concepts and how engineers use sound energy. Through hands-on activities and demonstrations, students examine how we know sound exists by listening to and seeing sound waves
Students learn about the types of seismic waves produced by earthquakes and how they move through the Earth. Students learn how engineers build shake tables that simulate the ground motions of the Earth caused by seismic waves in order to test the seismic performance of buildings.
The contents of this digital library curriculum were developed under a grant from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education, and National Science Foundation GK-12 grant no 0338326. However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.
How does the science work? Objects can become either positively or negatively charged through friction. In these experiments, the friction is created by rubbing a balloon on your head. Charged objects exert forces on each other that either attract or repulse.
I also tried to find experiments that would be easy to do with young kids. My toddler loves to participate with his older brothers. So every experiment here has been done with a toddler, and he was able to do all of them.
My toddler especially loved the magic milk science experiment. He had so much fun watching the colors swirl around, and then at the end, he slowly mixed the colors until it was a muddy brown. All you need for this one is milk, food coloring, and dish soap. The simple directions are on Laughing Kids Learn.
We tried this science experiment one day when it was raining outside. We filled a glass with water, covered it with shaving cream, and then dripped food coloring on top of the clouds. We had so much fun watching the colors work their way through the shaving cream and down to the water. It really does look like it is raining.
We just dropped food coloring onto our shaving cream, but I later saw on One Little Project that she mixed the food coloring with water first, and her rain looked a little better than ours, so next time we will probably try that, too. Our blue food coloring turned everything dark pretty quickly. Also, I got my shaving cream at the dollar store, and we have used it for lots of crafts and experiments.
My kids LOVED this one! They always want to repeat this science experiment, so I think that makes it a definite winner. It was super easy and all you need is vinegar, baking soda, and food coloring. I found this idea on Powerful Mothering (all the directions are on her site, as well).
Let your kids squirt, dump, or drop in vinegar. It will start to fizz, and then all of a sudden it will change colors. My boys loved the surprise of what color was coming up next. Make sure to place the cups on a tray or in a dish, so that they can catch all the exploding vinegar.
My sister told me about this fun experiment that she did. This one has two things that are not as common, but if you happen to have them around, or have time to hit the dollar store, this is a fun experiment to watch. You will need a jar, water or floral gel beads, and Alka Seltzer.
Put some gel beads in the bottom of the jar. I found three colors at the dollar store, so we put a little bit of each color in the bottom. Then fill the jar mostly full with water. Once the beads are all settled at the bottom, drop in the Alka Seltzer. Then watch the beads dance all through the water.
My boys loved watching what happened afterward, too. For some reason the pinks all floated, the purples sank, and the blues went back and forth. It made for a great discussion. And this is an easy one to replicate. Drop another Alka Seltzer in there and it will do it again.
While scientists, photographers, businessmen and experimenters laboured, the public became impatient. Photographers, eager to give their customers what they wanted, soon took the matter, literally, into their own hands and began to add colour to their monochrome images. As the writer of A Guide to Painting Photographic Portraits noted in 1851:
Several different processes and materials were used for hand-colouring, which proved to be a cheaper, simpler alternative to early colour processes. It provided studio employment for miniature painters who had initially felt threatened by the emergence of photography.
In skilled hands, effects of great subtlety and beauty could be achieved. However, even at its very best, hand-colouring remained an unsatisfactory means of recording colour; it could not reproduce the colours of nature exactly.
The scientific investigation of colour began in the 17th century. In 1666, Sir Isaac Newton split sunlight with a prism to show that it was actually a combination of the seven colours of the spectrum.
While this work was scientifically important, it was of limited practical value at first. Exposure times were long, and photographic materials sensitive to the whole range of the colour spectrum were not yet available.
The American photographer and inventor Frederic Ives devised a system based on three colour-separation negatives taken through coloured filters. From these negatives, positive transparencies were made which were placed in a special viewer, called a Kromskop. Mirrors in the Kromskop superimposed the images on the three transparencies and a second set of filters restored the colours.
The first process to use this method was devised by Dr John Joly of Dublin in 1894. Joly covered a glass plate with very fine red, green and blue lines (less than 0.1mm wide) in order to create a three-coloured filter screen.
When taking a photograph, this screen was placed in the camera in front of the plate. After exposure and reversal processing, the black-and-white positive image was carefully placed in register with another filter screen. The result was a colour transparency which could be viewed by transmitted light (light that passes through an object).
Next, charcoal powder was spread over the plate to fill any gaps between the coloured starch grains. A roller, using a pressure of five tons per square centimetre, was used to flatten out and spread the grains. The plate was then varnished to make it waterproof.
The final plate was a three-coloured filter screen: there were around four million transparent starch grains on every square inch of it, each grain effectively acting as a coloured filter. The final stage was to coat the plate with a panchromatic emulsion.
Following exposure, autochrome plates were reversal-processed to produce a positive image. When viewed by transmitted light passing through the plate, the millions of tiny red, green and blue-violet grains combined to give a full-colour photograph, accurately reproducing the colours of the original subject.
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