If you're interested in object motion and like taking mechanical objects apart to see how they work, then it sounds like you'd be interested in applied mechanics. Check out one of the Project Ideas below and you could find the science fair project you're looking for. Here are a few of the topics that are covered:
Projects
1.Soda Straw Robot Simulator.
2.Gears-Go-Round!
3.It's All in the Wrist: Moving Water with the Archimedes Screw Pump.
4.Understand Shock Levels and Packaging Principles.
5.Air Pressure and Rolling Resistance.
6.Physics of Vibrations.
7.Hey Gear Heads! The Physics of Bicycle Gear Ratios.
8.Effect of Temperature on Elasticity of Rubber Bands.
Soda Straw Robot Simulator
Objective
In this experiment you will use a simulator to test different robotic designs for stability.
Introduction
Robots may seem like a thing of the future, but robots make many contributions to today's world. There is the famous Mars Rover which collected samples and photographs on the planet Mars for scientists at NASA. There are underwater robots that help oceanographers explore deep sea vents. Robotic machines are very important in modern manufacturing. And there are, of course, some very cool toy robots that talk, sing, and even dance.
Each robot was designed for a purpose, to do a certain set of tasks. A robot has to be carefully planned with this purpose in mind by a mechanical engineer. The engineer will make sure that the robot is built such that its structure allows it to move in a way for it to complete its task. Then a software engineer will program the robot with the set of instructions it needs to perform the task.
Building a robot is a very labor intensive process, and so the engineers like to test out their design as much as possible before they commit to building it. One way to test a design is to make a computer model. Some advanced computer models allow you to run a simulation so that you can "see" how the robot will behave in certain conditions before you even build it. The engineer can then incorporate the information from the simulation to improve the robot design.
In this experiment you will use an online soda straw construction simulator to investigate different robotic designs. In the simulator, you can test different robot designs for stability while changing the variables for friction, gravity, or spring stiffness. What will happen to the design? Will all designs have the same dynamics and constraints?
Terms, Concepts and Questions to Start Background Research
To do this type of experiment you should know what the following terms mean. Have an adult help you search the internet, or take you to your local library to find out more!
- robot
- design
- simulator
- complexity
- friction
- gravity
- spring stiffness
Questions
- How do robots move?
- How are robots designed?
- Are complex designs better than simple designs?
Bibliography
- This project is based on the sodaconstructor Java application:
Soda, 2007. "sodaconstructor," London, UK: Soda Creative Ltd. [accessed February 10, 2007] http://www.sodaplay.com/constructor - This site from NASA offers a wealth of information about robotics:
NASA, 2007a. "Robotics Curriculum Clearinghouse - Lesson Plans and Educational Resources," National Aeronautics and Space Administration (NASA). [accessed February 10, 2007] http://robotics.nasa.gov/rcc/ - At this site from NASA you can read about the Mars Rovers and the exploration of Mars:
NASA, 2007b. "Mars Exploration Rover Mission," California Institute of Technology: Jet Propulsion Laboratory, National Aeronautics and Space Administration (NASA). [accessed February 10, 2007] http://marsrovers.nasa.gov/home/ - If you really like robotics, consider forming a team and compete in BotBall:
Botball.org, 2007 "Botball Homepage," Norman, OK: KISS Institute for Practical Robotics. [accessed February 10, 2007] http://www.botball.org/
Materials and Equipment
- Internet
- lab notebook
- pencil
Experimental Procedure
- Go to http://www.sodaplay.com/constructor. (The sodaconstructor site requires that you have java virtual machine (vm) installed on your computer.) Click the "click here to play" button. A new window will appear with a model of a walking soda robot. You can also choose your own model by clicking on the "file" button, but I recommend starting this project with the default file.
- Change the forces acting upon the design by changing the variables of the simulator. Try changing these variables of the model to test how the model responds to each variable (adapted from SODA, 2007):
- gravity (g) - Turn it up high and models are squashed by their own weight. Turn it down low and things float. You can even turn gravity upside down using the popup menu.
- friction (f) - Friction slows moving masses. Apply lots of friction and it's like moving in molasses. Apply low friction and things can move fast but might wobble out of control.
- spring stiffness (k) - Weak springs make models floppy. Very stiff springs are strong, but can make the model too jittery.
- What happens when you change the variables? Keep careful notes of what you do and what happens in a laboratory notebook.
- Analyze your results. Have you identified a variable that is important to the function of this design? What are the limits of this variable that allow the design to move and function? How much change, or flexibility, is there in the design?
- Change to another design file and test the variables in the same way. How does this design respond? Is it similar or different? Record your results in your lab notebook.
- After testing several designs, identify what makes some designs more robust than others. Which designs are most stabile to change? Which designs are the most flexible? Which designs are the most dynamic? Can you propose uses for each design based upon your results?
Variations
- In sodaconstructor, you can also change the design of the model and see how the movement of the design changes. Just follow these steps:
- Click on the drop down menu and change from "simulator" to "construct" so that the simulator stops moving.
- Change the design by clicking on any point (mass) in the drawing and moving it around. This will also change the length of the adjacent segments.
- Add new points and segments by clicking elsewhere in the edit screen. Each click will generate one new mass with an adjoining segment.
- Continue doing this to identify regions that are very important for the design to function, and those which are not as important for the function of the design.
- Can you make your own design? You can start from scratch, or use a file as a starting point and make modifications. How well does your design move? How stabile is it? If you create a good design, you can even submit it (with your parents permission) to the sodazoo.
- You can make a mock-up of these designs using soda straws and flexible connectors. Cut drinking straws to length using scissors. To make your joint push a small amount of clay into the end of the straw. Insert a small length of pipe-cleaner into the clay and attach to the next piece to form a flexible joint.
Objective
In this experiment you will count the number of teeth on gears and figure out how to calculate gear ratios by putting the gears together.
Introduction
What exactly do gears do? They crank, mesh, pump, push, pull, tug, and grind. All of which turn out to be very useful for doing work. Many mechanical contraptions and gizmos use them, but how do they do work? The LEGO Education Connection explains:
 |
| Moving gears (Public Domain). |
"A gear is a wheel with teeth on its outer edge. Gears rotate on a central axis and work with other gears to transmit turning force. The teeth of one gear mesh with — or engage — the teeth of another gear."The rotating force produced by an engine, windmill, or other device often needs to be transferred or changed in order to do something useful. For example, as you pedal a bicycle, you cause the sprocket to rotate. But in order to make the bike move, this rotating energy must be transmitted to the rear wheel.
"Gears are used to transmit turning force. They can also change the amount of force, speed, and direction of rotation." (LEGO, 2007)
Gears are generally used for one of four different reasons (Brain, 2000):
- To reverse the direction of rotation
- To increase or decrease the speed of rotation
- To move rotational motion to a different axis
- To keep the rotation of two axes synchronized
All of this, of course, depends on how the gears fit together. The most important thing to consider when putting two gears together is the gear ratio. This is a way of expressing the size of one gear relative to another. For example, LEGO makes gears in the following sizes: 40-tooth, 24-tooth, 16-tooth, and 8-tooth. An example of how to figure gear ratios follows (Genalo, 2000):
Line the first set of gears in front of you. |
In this experiment you will use a set of toy gears to figure out an alternate way to determine the gear ratio. You will also try to figure out how the gear ratio will affect the revolutions per minute of two gears that are meshed together. After figuring this out your inventions will only need a dab of imagination!
Terms, Concepts and Questions to Start Background Research
To do this type of experiment you should know what the following terms mean. Have an adult help you search the Internet, or take you to your local library to find out more!
- gear ratio
- driver
- follower
- gear up
- gear down
- How do gears work?
- What does a gear ratio tell you?
- How can gears be used for making things work?
Bibliography
- A very nice site explaining how gears work from LEGO Education:
LEGO, 2007. "Connections: Gears," LEGO Education: LEGO Group. [accessed February 3, 2007]
http://www.legoeducation.com/content/item.aspx?CategoryID=100&art=3 - This site describes gears in more general terms and has a nice animation of two gears turning:
Brain, Marshall, 2000. "How Gear Ratios Work ," HowStuffWorks.com [accessed February 2, 2007]
http://www.howstuffworks.com/gears.htm - Genalo, L., 2000. "Challenge Corner," Toying With Technology News, Iowa State University, volume 2, issue 1. [accessed February 3, 2007]http://www.eng.iastate.edu/twt/Pixandnews/newsletters/news/newsf00.pdf
Materials and Equipment
- a set of toy gears that fit together and come in a variety of sizes; Here are a few good ones that are available at national retailers like Amazon, Toys-R-Us, or Target:
- LEGO gear and building sets (best)
- Gears!Gears!Gears!® Gizmos by Learning Resources
- Kaleidogears by Quercetti Georello
- Gearation by Tomy
- different colored stickers or tape
- black permanent marker
- partner to help count
Experimental Procedure
- For this experiment you will need a data table to write all of your numbers:
Smallest <============> Largest Gear: A B C D E F Teeth of the Gear Teeth of Gear A Ratio of Teeth Turns of the Gear Turns of Gear A Ratio of Turns - Sort through your gear set to find a series of gears in different sizes that all fit together.
- Put the gears out on the table in order from smallest to largest.
- Place a small sticker or piece of colored tape next to ONE tooth of each gear, choosing a different color for each gear to help you keep track. Label each sticker with a letter (A, B, C, D, etc.) that you will use to identify that particular gear in your data table.
- Using a permanent black marker, color that SAME TOOTH black so that it stands out and is easy to see. Don't worry about the marker being permanent, you can wipe it off later with some rubbing alcohol.
- Count the number of teeth on each gear and write the numbers in your data table.
- To calculate a ratio, divide the number of teeth for each gear (found in the 1st data row of your table) by the number of teeth on Gear A (found in the second data row of your table). Write your answer in your data table (in the 3rd data row of this table).
- Check your math. Your ratio for Gear A should be 1:1, or 1.0 if you are using a calculator. If it is not be sure to check your math to be sure you are doing it right.
- Starting with the smallest gear (A), attach it to the next larger gear in size (B) using the connectors in your toy gear kit.
- Rotate until the two teeth marked with black permanent marker are directly next to each other. This will be your starting point.
- Now rotate the smallest gear slowly in one direction until the two marked teeth touch together at exactly the same point as before. Count the number of rotations of both gears as you go from start to finish. There may be a lot of turns to count! You can either find a volunteer to count the other gear for you (best way) OR you can complete this step twice, counting one of the gears each time from start to finish (most tedious way). Write the number of turns that each gear makes into your data table.
- Repeat this step with each of the larger gears (D, E, etc.) connected to the smallest gear (A) counting the number of revolutions for both gears each time.
- Again, calculate a ratio by dividing the number of turns of each gear (found in the 4th data row of your table) by the number of turns of Gear A (found in the 5th data row of your table). Write the answers in your data table (for example, the last row of this sample data table).
- Compare your two ratios. Are they similar or different? What does this tell you about how revolutions per minute are related to gear ratios?
Variations
- In this experiment you used the number of turns to calculate a gear ratio, by simplifying a fraction. Can you use the number of teeth in the two gears to get another fraction that will simplify the same way? Will this also calculate the gear ratio?
- In this experiment you tested the smallest gear against each of the larger gears. A more advanced project is to test all possible combinations of gears. Here is one way to make a table to help you figure out what all of the possible combinations are:
A B C D E A AA AB AC AD AE B - BB BC BD BE C - - CC CD CE D - - - DD DE E - - - - EE - Attention gear-heads! If you like gears and bikes, then this might be of interest to you. You can count the number of teeth on each gear of your bike and see if it relates to the rpm of your wheels. Just prop up your bike and crank the pedals with your hand at a constant speed. Then have someone help you count the number of turns the wheels make in a minute to get the rpm's. Check out a short description in the Additional Projects section on the Applied Mechanics interest area page.
- More advanced students can order specialized gears and calculate more complex gear ratios. You can also calculate how gearing up or gearing down will change the revolutions per minute. How is this useful for applied mechanics?
Objective
For this science project you will build an efficient Archimedes screw pump, using commonly found materials.
Introduction
Archimedes of Syracuse was born in the 3rd century BC. He was one of the most important inventors of his time because he liked to solve problems; particularly problems that would help his Italian hometown prosper. During the Siege of Syracuse, Archimedes developed the Archimedes heat ray, which used parabolic mirrors to focus the energy of the sun onto incoming enemy ships, and supposedly caught them on fire. For many years, several modern-day scientists didn't believe this kind of weapon could have been built. However, recently a group of students at MIT showed that an Archimedes heat ray weapon ispossible. Although, they do not claim that the story is completely true.
 Figure 1. Engraving of Archimedes of Syracuse. (eonimages.com, 2007.) |
The King of Syracuse requested that Archimedes build the biggest luxury ship possible. This ship proved to be leaky and Archimedes had to design a device to rid the hull of bilge water. So he designed theArchimedes screw. The screw was very effective because it got rid of the water and only required one person to operate it. The Archimedes screw was also used to transport water from low-lying areas up to irrigation ditches. The design is so effective that it is still being used in many modern-day applications. For instance, it is used to lift wastewater in treatment plants and even to lift water at the Shipwreck Rapids water ride at Sea World in San Diego, California. It's a tool that has never gone out of style.
The Archimedes screw is a positive-displacement pump. A positive-displacement pump traps an amount of fluid from a source and then forces the fluid to move to a discharge location. The Archimedes screw is made up of a hollow cylinder and a cylindrical core. The core sits inside of the hollow cylinder. Helical blades are wound around the core and are secured tightly against the hollow cylinder. The helical blades create pockets between the core and the inner wall of the hollow cylinder. To use this device as a pump, one end is placed in a low-lying fluid source and then tilted up into a discharge tank. To move water, simply rotate the screw. As the screw moves, it scoops up a small amount of water into the first pocket. On the next turn of the screw, the first pocket of water moves to the second pocket, and a new scoop of water enters the first pocket. This motion continues until finally the first scoop of water comes out at the other end.
 Figure 2. Here is an inside view of an Archimedes screw pump. The screw is turned and water is scooped up from the river and makes it's way up the screw pockets to the canal. (U.S. Department of the Interior, 2004.) |
The site of the fluid to be moved and the amount of fluid to be moved determine the outer radius of the Archimedes screw (the distance from the center of the core to the outer wall of the hollow cylinder), the length of the tool, and how much the tool has to be tilted (the slope). But there are other parameters that are utilized to optimize the efficiency of the screw; for instance, the inner radius (the distance from the center of the core to the inner wall of the hollow cylinder), the number of blades, and the pitch of the blades (Rorres, 2000). The pitch or period is the length of one cycle of the blade.
In this science project, step into Archimedes' shoes. Design the most-efficient pump using the materials listed in the Materials and Equipment list below. Have fun and remember that Archimedes loved solving difficult problems!
Terms, Concepts and Questions to Start Background Research
- Archimedes of Syracuse
- Archimedes screw
- Pump
- Radius
- Slope
- Pitch
- Period
Questions
- What other inventions did Archimedes develop?
- What areas of science did Archimedes study?
- What are some modern uses of the Archimedes screw?
- Can you explain how an Archimedes screw works?
Bibliography
- U.S. Department of the Interior. (2004, October 26). Hydraulic Research in Transition. Retrieved April 7, 2008 from the U.S. Department of the Interior Bureau of Reclamation website: http://www.usbr.gov/pmts/hydraulics_lab/history/transition/trans1.html
To learn more about Archimedes and his contributions, check out the following websites:
- Rorres, C. (n.d.). Archimedes. Retrieved April 7, 2008 from this New York University website:http://math.nyu.edu/~crorres/Archimedes/contents.html
- Wikipedia Contributors. (2008). Archimedes. Wikipedia: The Free Encyclopedia. Retrieved April 9, 2008 from http://en.wikipedia.org/w/index.php?title=Archimedes&oldid=210433020
Check out this site for information about the Archimedes screw, as well as an animation of how it works:
- Wikipedia Contributors. (2008). Archimedes Screw. Wikipedia: The Free Encyclopedia. Retrieved April 9, 2008 fromhttp://en.wikipedia.org/w/index.php?title=Archimedes%27_screw&direction=prev&oldid=205908572
- Rorres, C. (2000). The Turn of the Screw: Optimal Design of an Archimedes Screw. Journal of Hydraulic Engineering, Vol. 126, No. 1, 72-80. Retrieved April 9, 2008 from http://www.math.nyu.edu/~crorres/Archimedes/Screw/optimal/optimal.html
Materials and Equipment
- PVC pipe, ½-inch inner diameter, 2-foot length; available at hardware stores
- Clear vinyl tubing, 10-foot length, with a 3/8-inch outer diameter x ¼-inch inner diameter; available at hardware stores
- Clear vinyl tubing, 10-foot length, with a ¾-inch outer diameter x ½-inch inner diameter; available at hardware stores
- Strong and sticky tape, such as Gorilla tape or duct tape
- Permanent marker
- Retractable blade knife
- Lab notebook
- Liquid measuring cup
- Spoon
- Water
- Food coloring
- StyrofoamTM bowls, 12-oz (2)
- Tape (Scotch® tape works fine)
- Pen
- Books of various thickness or pieces of plywood board; available at hardware stores (1–2)
- Helper
- Graph paper
Experimental Procedure
Making Your Archimedes Screw
- Using the PVC pipe and the ¼-inch-inner-diameter vinyl tubing, take a piece of strong tape and tape one end of the tubing to the outside of one end of the pipe such that a ¼-inch length of tubing is hanging off the end.
- Carefully wrap the tubing around the pipe in regular intervals until you come to the other end of the pipe. From that point, add a ¼ inch and mark that spot on the vinyl tubing with a permanent marker.
- Unwrap the tubing and cut it with the blade knife at the mark. Ask an adult for assistance when using the knife.
- Rewrap the cut piece of tubing around the pipe in regular intervals and tape it down with pieces of strong tape along the pipe. There should be a ¼-inch of tubing hanging off both ends of the pipe, past the sections that you taped down. The starting section will reach into the water, allowing it to travel through the tube and the end section will help get the water out. By wrapping the tubing in regular intervals you are establishing the period of the tubing.
- Count the number of times you have wrapped the tubing around the PVC pipe. Divide 2 feet (the length of the PVC pipe) by the number of times you wrapped the tubing around the PVC pipe. This value is the period and is in units of feet. Note this down in your lab notebook in a data table similar to the one shown at the bottom of the Experimental Procedure.
 Figure 3. Experimental Archimedes screw. |
Setting Up Your Bowls
- In your liquid measuring cup, mix a few drops of food coloring in 1 cup of water. This makes the water easier to see.
- Now make tape loops with the Scotch tape to stick to the bottom of one of the Styrofoam bowls and press the bowl onto a table so it stays in place.
- Pour a ½ cup of the colored water into the other Styrofoam bowl. With a pen, mark the level of the water on the bowl. Pour the water back into the measuring cup.
- Making more tape loops, carefully tape the marked bowl onto one of the books or plywood boards so that it will stay in place during the experiment. The bowl on the book or plywood is the discharge bowl.
Testing Your Experimental Setup
- Now you are ready to test your experimental setup and determine what slope works best so you can run your trials. Place the marked bowl on the book or plywood about 2 feet away from the bowl taped to the table. Pour the 1 cup of water into the bowl on the table.
- Place your Archimedes screw across the two bowls, as shown in Figure 4. Be sure the extra ¼ inch of tubing hanging off the end is in the bowl of water on the table. Turn the screw so that every time the end of the tube goes into the water it scoops up some of the water.
- Tilt the screw so that one end is in the water and the other end is in or close to the bowl that you want to move the water to, which in this case, is the bowl taped to the book or plywood.
Figure 4. Experimental setup. - Make sure that as you turn the screw, the water doesn't fall back out of the screw. If the water does fall out, adjust the tilt of the screw, the placement of the bowls, and/or the height of the discharge bowl. Use an extra book or board if needed.
- Turn the screw a few times to make sure that the water is traveling through the tubing. Experiment with how fast you can turn the screw and still move water through the tube. Going too fast might not lead to positive results.
Running Your Trials
- Now you're ready to start running your trials. Hold the screw vertically and empty all of the water from the tubing and the discharge bowl back into the bowl on the table.
- Using your permanent marker, make a mark on the middle of the pipe at the position when the vinyl tubing is just about to enter the water. This will help you keep track of the number of turns you make. Turn the pipe so the mark is facing up, and then start turning the screw until the mark is facing up again. You have made one turn and should see some water in the tubing. On each successive turn, the tubing should be completely under water so that you scoop as much as possible.
- Continue turning the screw until a ½ cup of water is in the discharge bowl. Make sure that you maintain the same tilt the whole time you are turning the screw. Also make sure that you are scooping up water on every turn. Have your helper help you count the number of turns as you go along. You can gauge when you have about a ½ cup in the discharge bowl, based on the pen marking you made when you first started. To be exact, confirm that you have a ½ cup of water in the discharge bowl by pouring it into the measuring cup. One person should hold the screw in place and the other person should carefully remove the bowl from under the screw and measure the water.
- If the amount of water in the discharge bowl is not a ½ cup, continue turning the screw until you get a ½ cup.
- If the amount of water in the discharge bowl is greater than a ½ cup, empty all of the water back into the first bowl and restart this step.
- Keep track of the number of turns it takes to move a ½ cup of water from the starting bowl into the discharge bowl. Note this information in your lab notebook.
- Repeat "Running Your Trials" two more times. Every time that you start a new trial, empty all of the water back into the measuring cup. Make sure that you have a full cup of water at the start of each trial. If you do not, then add water into the measuring cup until you have 1 cup. For each trial, note the information in your lab notebook.
- Calculate the average of the results of the three different trials and record them in your data table.
- Now unwrap the ¼-inch-inner-diameter tubing from the pipe. Take the ½-inch-inner-diameter tubing and wrap that around the ½-inch-inner-diameter PVC pipe. Use the same period as you did for the ¼-inch tubing. Wrapping this tubing will be harder than it was with the ¼-inch tubing because the tubing is larger and stiffer. Have your helper assist you with wrapping. Repeat the entire experiment with the new Archimedes screw. Remember to record the data you collect in your lab notebook.
- Plot your data. Label the x-axis Design and the y-axis the Average Number of Turns to Move a ½ Cup of Water. Which design is more effective at moving water? Why?
| Design | Period | Number of Turns to Move ½ Cup of Water | |
| ¼-inch tubing wrapped on ½-inch pipe | Trial #1 | ||
| Trial #2 | |||
| Trial #3 | |||
| Average of all trials | |||
| ½-inch tubing wrapped on ½-inch pipe | Trial #1 | ||
| Trial #2 | |||
| Trial #3 | |||
| Average of all trials | |||
Variations
- Change the period of the tubing to increase or decrease the number of wrappings and investigate how this affects the number of turns it takes to move ½ cup of water from the bowl on the table to the discharge bowl.
- Change the diameter of the pipe. Try using a 2-foot-long, 1-inch-inner-diameter PVC pipe with the ¼-inch-inner-diameter vinyl tubing. Does it make a difference?
Objective
The goal of this project is to investigate the effect of material properties on shock levels and protection against shock damage.
Introduction
Products we use every day come in all shapes and sizes. Most products come in some type of packaging to protect them from damage while they are being transported. Companies spend a lot of money on designing the right package for their product.
This experiment is meant to help you explore how material properties such as hardness and weight can affect shock levels observed during drop testing. The material properties of the product being dropped, the packaging, and the surface it is being dropped onto are all important in determining the amount of shock received. This project is intended to help you understand what types of material make effective and cost effective packaging to protect products from damage.
Terms, Concepts and Questions to Start Background Research
To do this project, you should do research that enables you to understand the following terms and concepts:
- standard measure for material hardness,
- comparison of hardness for common materials,
- measuring shock amplitudes,
- common packaging materials and their cost.
Questions
- Do you think dropping your product on a hard floor from 1 foot would cause more damage than dropping your product on a carpeted floor from 4 feet?
- What would be a realistic drop distance for your product to survive during shipping? How about after shipping, once it has been removed from its packaging? For example, is it reasonable to expect a product to withstand a drop of 10 feet?
Bibliography
- NPL, 2006. "What are 'g-forces' and are they caused by gravity?" National Physical Laboratory, U.K. [accessed March 22, 2006] http://www.npl.co.uk/force/faqs/gforces.html.
- This is a high-school level tutorial on free fall and the acceleration due to gravity:
Henderson, T., 2004. "Introduction to Free Fall," The Physics Classroom, Glenbrook South High School, Glenview, IL [accessed March 22, 2006]http://www.glenbrook.k12.il.us/gbssci/phys/Class/1DKin/U1L5a.html.
Materials and Equipment
To do this experiment you will need the following materials and equipment:
- 3 samples of material or an object to be dropped (examples below). You may want to use multiple sizes/weights of each of these:
- rubber,
- wood,
- metal,
- styrofoam.
- 3 samples of various surfaces to be dropped on (examples below):
- wood,
- concrete,
- foam,
- pillow,
- carpet,
- tile.
- 3 samples of material to be used in packaging (examples below):
- bubble wrap,
- packing peanuts,
- tissue,
- styrofoam,
- plastic filled with air,
- newspaper.
- packaging container (choose 1— examples below):
- cardboard box,
- large plastic (i.e. Ziploc) bag,
- shipping envelope.
- tape measure or ruler,
- tape,
- chair or ladder,
- 1–2 resettable shock indicators (50 G level) search Web for these, example brand names are "Drop-N-Tell" and "TelaDrop" (see Variations section for possible alternatives).
Experimental Procedure
- Set up your materials and equipment for testing.
- Determine the material(s) and size(s) of product you plan to drop.
- Identify the 3-4 surfaces you plan to use to drop the product onto. You can choose to go to the location of the surface or, if it is portable (e.g., a small sample of carpet, wood, etc.), then collect the samples and bring them to one central location for testing.
- Create a table listing the variables (material, size, and surface).
- Secure the tape measurer or ruler in a vertical position against a non-movable surface like a wall. (This will allow you do your experiment using two hands.)
- Tape the resettable shock indicators to one side of the first product you are dropping.
- Predict the outcome of the drop testing.
- Formulate a hypothesis about how you expect the material type, material size, or surface type to affect the distance the product can be dropped before it activates the shock indicator.
- For example, your hypothesis might be "I think a smaller piece of X when dropped on a surface of Y will activate the shock indicator at the shortest distance from the surface."
- Determining the shock threshold of product on each of the various surfaces.
- Take your first product and first surface and drop the product from 1 foot above the surface.
- Verify whether shock indicator was activated.
- Record material, surface, and shock activation (yes/no) in the table.
- If shock indicator was not activated, then increase distance (you can decide what interval).
- Repeat the experiment and record the results.
- Continue until you get to a level where the shock indicator is activated.
- Repeat the experiment with the remaining surfaces, making sure you reset shock indicator each time it is activated.
- Repeat the entire experiment with second and then third products selected. Test against all three surfaces.
- Summarize your findings and compare them to your predicted results. What did you learn?
- Predict the outcome of testing with different packaging materials.
- Formulate a hypothesis about how you expect different packaging material to affect the distance the product can be dropped before it activates the shock indicator.
- For example, your hypothesis might be, "I think using bags filled with air will protect the product at higher drop distance than using tissue."
- Test various packing materials.
- Choose the packaging materials you will be using.
- Create a table for recording the packaging material, the distance dropped, the surface it is dropped on, and whether the shock indicator was activated or not.
- Choose one of your product samples from your first experiment, place it in your packaging container, and fill the container with the first packaging material.
- Make sure that the packaging material completely surrounds the product.
- Tape the packaging container closed.
- Choose one surface to perform your experiment on (perhaps the 'worst case' from your first experiment).
- Drop your package from the same distance that had previously activated the product in the first part of this experiment. Record whether the shock indicator was activated or not.
- If not, continue to increase the distance and repeat the experiment until the shock indicator is activated. Record your results after each drop.
- Repeat the experiment with other packaging materials and record the results.
- Summarize your findings and compare them to your predicted results. What did you learn?
Variations
- An alternative to using the shock indicators would be to use:
- an egg, or
- an impact-activated sound toy, or
- an impact-activated lighted toy (you would need to be able to see through the packaging to know if the light was activated).
- Determine how small the product packaging can be and still protect the product at the desired drop distance—packaging does cost money.
- Renewable resources and packaging. Do research on the materials commonly used in packaging. Which materials can be made from renewable resources? Can renewable materials effectively protect against shock? Would using renewable materials add to the cost (e.g., if more material is needed to provide effective protection)?
| * Note: This is an abbreviated project idea, without notes to start your background research or a procedure for how to do the experiment. You can identify abbreviated project ideas by the asterisk at the end of the title. If you want a project idea with full instructions, please pick one without an asterisk. |
Abstract
How does the air pressure in a tire affect the rolling resistance of a bicycle or wheelbarrow? Do you need more or less effort to move the bicycle (or wheelbarrow) as the air pressure is changed? Use a tire pressure gauge to monitor air pressure (don't exceed the recommended tire pressure). For the bicyle, you could probably use a spring scale to measure how much force is needed to pull the bicycle along (have a friend lightly touching the bike to keep it balanced). Quantifying the force needed to move the wheelbarrow will be a bit more difficult. You may have to resort to a 1–5 rating scale (e.g., where 1="I can do this all day," 2="takes a bit of effort," 3="a good workout," 4="pushing myself pretty hard," and 5="maximum effort.") For more advanced students, can you explain your results in terms of frictional forces?| * Note: This is an abbreviated project idea, without notes to start your background research or a procedure for how to do the experiment. You can identify abbreviated project ideas by the asterisk at the end of the title. If you want a project idea with full instructions, please pick one without an asterisk. |
Abstract
Tennis racquets, baseball bats and golf clubs all vibrate when they hit the ball. You can often feel it in your hands, particularly if you "mis-hit" the ball. You can find the point(s) on your racquet, bat or club—called the "sweet spot"— that minimize unwanted vibrations. Low-tech method: hang the racquet or bat straight up and down with a string from its handle. Lightly hold the handle with your thumb and forefinger and have a helper sharply tap the bat, strings or club face with a ball at regular increments along the length. You'll feel a minimum in the vibration at the "sweet spot" of the bat, racquet or club. High-tech method: loosely tape a card to the handle so that it will vibrate when the racquet, bat or club is tapped (Brody, 1987, p. 33). If you want to go all out, you can measure the vibration of the card by monitoring light reflecting off the card with a photodiode and analog-to-digital converter. Several projects possible: longest hit from where? best accuracy from where? comparing different racquets for comfort? (Both Brody et al., 2002, and Brody, 1987, have extensive sections on the vibration of racquets; Barr, 1990, pp. 37–39, has a short treatment of vibration in baseball bats.)Bibliography
- Barr, G., 1990. Sports Science for Young People. New York, NY: Dover Publications.
- Brody, H., 1987. Tennis Science for Tennis Players. Philadelphia, PA: The University of Pennsylvania Press.
- Brody, H. et al., 2002 The Physics and Technology of Tennis. Solana Beach, CA: Racquet Tech Publishing.
| * Note: This is an abbreviated project idea, without notes to start your background research or a procedure for how to do the experiment. You can identify abbreviated project ideas by the asterisk at the end of the title. If you want a project idea with full instructions, please pick one without an asterisk. |
Abstract
If you have a multi-speed bike, you know that you can make it easier or harder to pedal just by shifting gears. Ever wonder how that works? You can investigate this a number of ways. A basic approach is to use a selection of spools of thread (with different diameters), a board with two nails, and a rubber band. Place a spool over each nail, and put the rubber band over them. Mark the 12:00 position on each spool so that you can count revolutions. Turn one spool through a full circle and note how far the second spool turns. Try with different combinations of spool sizes. Explain how your results relate to bicycle gears. You can also do this with a multi-speed bike: turn the bike over, and mark a position on the rear wheel with tape so you can count revolutions. Or, maybe your bike has a speedometer and cadence monitor (this uses magnets on the crank and wheel, and fixed sensors mounted on the frame to count). Have a helper hold the rear wheel up while you move the pedal at a fixed cadence (make sure there is no slack in chain). Record the resulting speeds for each gear combination. Count the teeth on the front sprockets and rear gears. Divide the number of teeth in front by the number in back for each gear combination. Knowing the wheel circumference, you can calculate the wheel's angular speed (revolutions per minute, or rpm's) from the recorded speed. Graph your results. Is there a relationship between the ratio of the gear teeth and wheel rpm's? (Idea from Wiese, 2002, pp. 62–67.)Bibliography
Wiese, Jim. Sports Science: 40 Goal-Scoring, High-Flying, Medal-Winning Experiments for Kids. New York: John Wiley and Sons, 2002.| * Note: This is an abbreviated project idea, without notes to start your background research or a procedure for how to do the experiment. You can identify abbreviated project ideas by the asterisk at the end of the title. If you want a project idea with full instructions, please pick one without an asterisk. |
Abstract
How much force can a rubber band withstand before breaking? Do rubber bands that stretch longer take more or less force to break? How does the elasticity of a rubber band change with temperature? Use a spring scale to measure the applied force, and a meter stick or ruler to measure the change in length. Recording with a video camera (or possibly two) can help you to capture the values at the moment before the rubber band breaks. You can change the temperature of the rubber bands using heated or cooled water. (Coy, 2005)Bibliography
Coy, A.R., 2005. "How Does Temperature Affect a Rubber Band's Elasticity?" California State Science Fair Project Abstract [accessed April 18, 2006] http://www.usc.edu/CSSF/History/2005/Projects/J0204.pdf
