Areas of Science Aerodynamics & Hydrodynamics
Science With Your Smartphone
Time Required Short (2-5 days)
Prerequisites None.
Material Availability Readily available
Cost Low ($20 - $50)
Safety Adult supervision is needed for using matches, lighting candles and handling lit candles.
google science journal candle carousel summary  
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Have you ever ridden on a carousel, or a merry-go-round, at an amusement park? On a carousel, you usually get to take a seat on a wooden horse or other animal that spins around and around as the carousel is turned on and powered by electricity. Another smaller type of carousel that people can have in their homes is a candle carousel, which is powered by heat from candles. In this science project, you will get to make your own candle carousel and investigate how the spinning speed of the carousel is related to the number of candles you use to power it. You can even record the number of rotations your carousel makes using Google's Science Journal app. How fast can you make it spin?


Investigate the relationship between the number of lit candles under a candle carousel, and how fast the carousel spins.

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Teisha Rowland, PhD, Science Buddies
Edited by Svenja Lohner, PhD, Science Buddies
  • Play-Doh® is a registered trademark of Hasbro, Inc.
  • Elmer's® is a registered trademark of Elmer's Products, Inc.

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General citation information is provided here. Be sure to check the formatting, including capitalization, for the method you are using and update your citation, as needed.

MLA Style

Rowland, Teisha. "Take a Candle Carousel for a Spin." Science Buddies, 4 Aug. 2020, Accessed 1 Mar. 2021.

APA Style

Rowland, T. (2020, August 4). Take a Candle Carousel for a Spin. Retrieved from

Last edit date: 2020-08-04


A candle carousel spins around like an electricity-powered carousel, or merry-go-round, that you might have ridden at an amusement park. But a candle carousel is much smaller—some can fit in the palm of your hand—and it is powered by heat from candles. Figure 1 shows an example of a candle carousel. Note how the candle carousel has several tilted blades at the top, how the blades are all attached to a central shaft, and that there are candles placed below the blades. When the candles are lit, hot air rises above them, which makes the blades spin around.

Four candles in an aluminum pie pan with a fan above them
Figure 1. In this science project, you will make a candle carousel similar to this one. When the candles are lit, they cause the blades at the top to spin.

Candle carousels are part of the German Christmas tradition. Known as Christmas pyramids, or candle pyramids, these German crafts traditionally depict winter or religious themes like in Figure 2. They were invented in the early 1800's; long before electrical power was in homes.

A German Christmas Candle Pyramid has a tower with 3 levels and a fan placed on top
Figure 2. An example of a Christmas candle pyramid.

How does lighting the candles make the candle carousel spin? The candle's flame heats up the air above the candle. Heat is a form of energy, and it makes the air right above the candle rise above the colder air around it. This rising hot air pushes up against the blade above it. Because the blade is tilted, this push causes the blade to move sideways (to the right or left, depending on how the blade is tilted), and spin around the shaft. Each blade that moves above the flame also gets "pushed" by the hot air.

The rising hot air exerts a force on the blade, which makes it move. A force is something that pushes or pulls on something else. The force that moves the blade sideways is called lift. Normally, we think of lift as an upward force, such as with flying airplanes. However, for an airplane, air is coming toward the airplane from straight in front of it, whereas with a blade on the candle carousel, the air is going upwards, hitting the blade from below. Because lift is defined relative to which way the air is going, in a candle carousel the lift is a sideways force. Another force acting on each blade is the force of drag, which pushes upward against the blade, in the same direction as the moving air. Figure 3 shows a diagram of how the hot air and forces of lift and drag act on a candle carousel's blade to make it move. (This is very similar to a wind turbine, which you can find out more about in the project idea Unleash the Power of a Pinwheel!.)

Force diagram of hot air, lift and drag acting on a fan blade

An angled blade edge experiences lift and drag when heated from underneath by air. Hot air rises underneath an angled blade edge and lift pulls the blade perpendicular to the hot air and towards the blades lowest edge. Drag pulls the blade edge in the same direction that air moves over it.

Figure 3. This diagram shows how hot air, drag, and lift act on a blade of a candle carousel to make the blade move (rotating around the central shaft; the shaft would be directly behind the blade [the shaft is unseen in this diagram], and the blade would rotate to the left in this diagram). Note that this diagram is only showing the edge of the blade, as if the viewer is looking directly at the blade's edge.

In this science project, you will make your own candle carousel, like the one in Figure 1, and investigate how the amount of heat—generated by a varying number of lit candles—under the carousel's blades affects how fast the blades spin. You will measure the speed of the blades in rotations per minute, or rpm. Will adding more candles make the blades spin faster, or will there be no noticeable difference? What will the relationship be? Get ready to make your own candle carousel to find out!

Terms and Concepts

  • Candle carousel
  • Heat
  • Force
  • Lift
  • Drag
  • Wind turbine
  • Rotations per minute (or rpm)


  • How does lighting a candle on a candle carousel make its blades move?
  • What direction is the force of lift on the blades of a candle carousel?
  • Why are the blades in a candle carousel tilted?
  • Why does hot air rise?


To find out more about the forces involved in making the candle carousel work, you can check out these resources:

  • National Aeronautics and Space Administration. (NASA). (2014, June 12). Dynamics of Flight.. Retrieved January 20, 2015.
  • Wikipedia contributors. (2015, January 5). Wind turbine. Wikipedia: The Free Encyclopedia. Retrieved January 20, 2015.
  • How Stuff Works. (n.d.). How Wind Power Works.. Retrieved January 23, 2015.

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Materials and Equipment

  • Aluminum pie pans, 8 3/4 inch in diameter (2)
  • Printer with printer paper
  • Scissors
  • Tape
  • Ruler, metric
  • Protractor
  • Black permanent marker
  • Plastic drinking straw
  • Metal hex nut
    • It should snugly fit around the straw, and be high enough to stably stand upright with the straw in it.
    • The nut size used in this project had 1/4 inch inner diameter, 1/2 inch outer diameter, and a height of 1/4 inch.
    • We recommend that you take your straw to a hardware store and try different-sized hex nuts to make sure you find the one that fits your size straw best, since straws can vary in diameter.
  • Heavy duty mounting tape, double-sided
  • Play-Doh® (a piece approximately the size of your fist)
  • A wooden skewer, at least 20 cm long, with a sharp point
  • Small candles (4). They should be about 5 cm tall. A set of 12 candles that work well for this project can be purchased from
  • Lighter or matches
  • Lab notebook
  • Adult helper for lighting candles
  • A piece of aluminum foil
  • Flashlight
  • A pile of books or box to elevate your phone
  • Optional: Colored permanent markers for decorating the candle carousel
  • A smartphone or tablet to record your data
    This project uses Google's Science Journal app, a free app that allows you to gather and record data with a cell phone or tablet. You can download the app from Google Play for Android devices (version 4.4 or newer) or from the App Store for iOS devices (iOS 9.3 or newer).
    Note: This project was tested with the Android version of Science Journal in which light intensity is measured using the ambient light sensor and given in lux. The iOS version uses the phone's camera to measure brightness resulting in data expressed in EV (Exposure Value). Lux values and Exposure Values are not the same. Whereas Exposure Value is a base-2 logarithmic scale, the lux scale is linear. This might affect your data and result in different values and graphs when you are using an iOS version of the app—both versions will work for this project though. The graph examples given in the procedure show light intensity in lux.
  • If you do not have a smartphone, you can use a timer or stopwatch instead

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Experimental Procedure

In the first part of this science project, you will build your candle carousel. Once you have confirmed that it works, you will use use Google's Science Journal app to measure how fast it spins using different amount of candles. Science Journal is an app that lets you record data using sensors that are built into many smartphones, including a light sensor which measures light levels (normally this sensor is used to automatically adjust the brightness of your phone's screen). To learn how to use the Science Journal app and how to use the light sensor, you can review the relevant tutorials on this Science Journal tutorial page. In this project, you will use the app to record the rotations of your carousel using your phone's light sensor. You will do this by having part of your carousel pass between the phone and a light source, so it will block the light sensor and affect the reading. If you do not have a phone, you can also count the carousel rotations using a stopwatch.

Constructing Your Candle Carousel

In this part of the science project, you will make your own candle carousel from two aluminum pie pans, a straw, a metal nut, candles, Play-Doh, a wooden skewer, and some double-sided mounting tape. You will also need a pair of scissors, tape, and a printer with paper. So gather your materials and get ready to build it!

  1. Take one of the aluminum pie pans (Figure 4) and carefully cut off its tilted rim so that it now looks like a flat, aluminum circle, as shown in Figure 5.
An aluminum pie pan
Figure 4. Take one of the aluminum pie pans.

A circle of aluminum from a pie pan with the walls cut off
Figure 5. Cut the rim off of the aluminum pie pan (so you are left with a flat circle of aluminum).
  1. Print out the windmill template (PDF).
  2. Cut the circle out from the template and tape it to the aluminum circle with a couple of pieces of tape, as shown in Figure 6. Do not use too much tape as you will be removing the paper template later.
A paper windmill template is taped to an aluminum circle
Figure 6. Tape the cut-out windmill template to the aluminum circle.
  1. Cut along the solid lines of the template and the aluminum circle below it, as shown in Figure 7.
    1. Be sure not to cut all the way to the center of the circle.
Cuts are made to an aluminum circle following a paper windmill template that is taped on
Figure 7. Cut the aluminum circle along the solid lines of the template.
  1. Carefully fold the aluminum circle down along the dotted lines of the template, so that you have triangular edges pointing down, as shown in Figure 8.
    1. You can use a ruler to help make sure the lines are straight.
    2. Use a protractor to make sure the edges are bent down by about 30–40 degrees (°) compared to the top, flat strips.
Angled fan blades are made by folding sections of cut aluminum along the lines of a template
Figure 8. Fold the aluminum circle down along the dotted lines.
  1. Gently remove the paper template from the aluminum circle, which should now look like an aluminum windmill, as shown in Figure 9. You will need to remove the paper template for your candle carousel to work.
A windmill with angled blades made from the bottom of an aluminum pie pan
Figure 9. Gently remove the paper template from the aluminum windmill.
  1. Optional: At this point (or at a later point), you can decorate the blades of the windmill (using colored permanent markers) if you would like to. Figure 10 shows one example of some decorated blades.
The blades of an aluminum windmill are decorated with markers
Figure 10. Decorated windmill blades.
  1. Flip the windmill over so that the triangular edges are pointing up. In the center of the windmill, make a small dot using a permanent marker, as shown in Figure 11.
    1. You should use a ruler to find the center by measuring along the length of each flat strip and calculating where the center of each of the strips is; where they all intersect is the center.
The center of an aluminum windmill is marked with a black dot
Figure 11. Use a permanent marker to make a dot in the center of the windmill, on its underside.
  1. Cut a straw to make a straight piece that is 5 centimeters (cm) long. Make sure the straw piece fits snugly in the metal hex nut you have. If needed, you can put a layer of tape around the straw to make it fit better.
  2. Use the double-sided mounting tape to attach the nut and straw piece onto the dot you made on the aluminum windmill. The nut should help hold the straw piece straight up (vertically). When it is attached, your windmill should look like the one in Figures 12 and 13.
    1. Only place the double-sided tape along the rim of the nut. Spare out the hole completely, otherwise the carousel might get stuck on the tape during spinning, which could later interfere with the ability of the windmill to smoothly spin on the skewer. It is fine if the tape reaches outside of the nut as long as there is no tape covering the hole.
    2. Make sure you can see the dot when looking down through the straw; it should be centered on the dot.
  3. Note: It is important to make sure that the straw is as vertical as possible. If the straw is not pointing straight up, the candle carousel blades will not work well. Look straight down at the straw (from the top), and from all sides, to make sure it is pointing up straight.
A nut is placed on the center of an aluminum windmill and a straw is placed inside the nut
Figure 12. Side view of the straw (inside the nut) and nut being attached to the windmill.

Top-down view of a straw inside a nut placed on the center of an aluminum windmill
Figure 13. Top view of the straw (inside the nut) and nut being attached to the windmill.
  1. Continue with making the candle carousel's stand. This will be made using the other aluminum pie pan. Take the other aluminum pie pan and use a permanent marker to make a dot in the center. Then make four dots around the edge of the pan that are all equally spaced apart, and an "X" next to each dot, as shown in Figure 14. (You will later be placing a candle on each "X.") Note: Be sure you use a ruler to measure and make all of the dots.
An aluminum pie pan has five black dots marked at the north, east, south, west and center of the pan
Figure 14. On the second aluminum pie pan, make a dot in the center, and four dots (with an "X" next to each) equally spaced along the edges.
  1. Next, cut (or break) a wooden skewer so that it is 20 cm long (and still has one pointed end). Then take a small fist-sized piece of Play-Doh and stick the flat end of the skewer into it. Place the Play-Doh and skewer onto the center dot of the aluminum pie pan. Be sure the skewer is right on the dot. Press down on the edges of the Play-Doh ball to flatten it onto the pie pan a little so that it looks like Figure 15. You can also use the double-sided tape to attach the Play-Doh onto the pan.
A wooden skewer is stuck vertically into a ball of Play-Doh at the center of an aluminum pie pan
Figure 15. Place the wooden skewer into a piece of Play-Doh, and stick that onto the center of the aluminum pie pan.
  1. Make sure that the skewer is as vertical as possible in the Play-Doh on the pan. (For the candle carousel to work well, the skewer needs to be as straight as possible.) Let the Play-Doh harden a bit by letting the candle carousel's stand sit out for a while.
  2. In the meantime, cut a strip of aluminum foil, about 4 inches long and 1 inch wide. Use tape to attach it to the horizontal, flat part of one of the blades as shown in Figure 16. When the candle carousel is spinning, the aluminum strip will block the light from reaching your phone every time it passes the light sensor. This way you will be able to count how many rotations your carousel makes.
A small aluminum strip is added to a blade on a windmill to increase its length from the center
Figure 16. Attach an aluminum strip to the horizontal part of one blade that will block your phone's light sensor when the carousel is spinning.
  1. Once the Play-Doh has hardened, you can try out your candle carousel! Place the windmill's straw onto the top of the skewer. Test if your windmill spins smoothly by spinning it with your hands. If you feel a lot of resistance or you notice irregular spinning movements, check if the tip of the skewer got stuck onto the double-sided tape that you used to attach the nut to the pan. You want it to spin evenly and very smoothly. Next, place one candle on each "X" on the carousel's stand. Your setup should now look like Figure 17.
Four candles in an aluminum pie pan with a fan above them
Figure 17. Place the straw's windmill onto the pointed tip of the wooden skewer, and a candle on each of the four dots around the stand's edge, and your candle carousel is ready to try out!
  1. Try out your carousel to make sure it works! To do this, set it up on a flat, stable surface (such as a table or desk) that is not near any source of air movement. For example, set it up in a room with closed doors and windows, and away from any active air vents. Even a gentle breeze can completely disrupt the candle carousel's movement.
  2. Now have an adult help you light all four candles. Watch to see if the candle carousel's blades (the windmill part, on top) start to spin. Again, check if the spinning movement is regular and smooth. You may need to wait for a minute before you see any movement. Once it is working, you can move on to the next section, "Testing Your Candle Carousel." If the blades do not spin after waiting for 2–3 minutes (min), try to troubleshoot by checking the following:
    1. Make sure the candle flames are completely upright and are not flickering or moving sideways. If they are flickering or moving sideways, there may be air movement that is disrupting them. The flames need to be completely upright for the candle carousel to work well; if the flames are not upright, the hot air will not be moving directly upward to the blades.
    2. Make sure the windmill part is sitting horizontally on the skewer (and parallel to the carousel's stand). If the windmill is tilted on the skewer, the straw may be rubbing the skewer (creating friction) and preventing the blades from spinning.
    3. See if there are any other possible sources of friction that could be slowing down the blades' spinning. To do this, look at where the skewer and straw meet. The skewer should ideally only touch the aluminum on the windmill where you drew the dot (within the nut). It should not touch any double-sided tape that you used to attach the hex nut to the pie pan.
    4. Make sure the blades are all at a 30° angle, and that the straight strips on the windmill are still straight and horizontal (and parallel to the carousel's stand).
    5. The aluminum strip should be too light to affect the balance of the candle carousel. However, if you feel that it poses a problem, try to make it shorter or narrower to minimize its effect on the spinning behavior.
    6. You could try making the skewer shorter, as this will decrease the distance that the hot air has to travel from the flames. If you do this, blow out the candles, remove the windmill part from the skewer, and try to carefully pull the skewer straight out of the Play-Doh. When you make the skewer shorter, make sure the windmill's blades will still be at least about 5 cm above the flames of the lit candles. Stick the shortened skewer straight back into the Play-Doh hole and try the candle carousel again.

Testing Your Candle Carousel

In this part of the science project, you will investigate how the amount of heat (the number of lit candles) under the carousel's blades affect how fast the blades spin. You will use Google's Science Journal app and your phone's light sensor to measure and record the speed of your carousel. This is how it works: once you shine light on your phone from above, the light sensor will read a high light intensity value. However, if something blocks the light from reaching the sensor, the light intensity will immediately decrease sharply. When you place your phone next to the candle carousel so that the aluminum strip blocks the light sensor every time it passes above it, then you will get a dip in light intensity for every rotation your candle carousel makes. From that you can derive the carousel speed, or its number of rotations per minute (or rpm). Alternatively, you can also count the carousel's rotations with the help of a stop watch.

In your lab notebook, make a data table like Table 1. You will be recording your results in this data table.

  Rotations per Minute (rpm)
Number of Lit Candles Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Average
Table 1. Make a data table like this one in your lab notebook in which to record your results.

Using the Science Journal App

  1. Before you start taking your measurements, make sure you know the location of the light sensor in your phone and test if it works as expected. The light sensor tutorial on the Science Journal tutorial page explains how to do this.
  2. Once you have set up your carousel and tested your light sensor successfully, place the phone next to the carousel with the light sensor facing upwards. Use several books or a box to elevate your phone so it sits just underneath the aluminum strip. Position the phone so that the aluminum strip blocks the light sensor every time it is above the phone as shown in Figure 18. Make sure that the movement of the carousel is not hindered in any way.
A flashlight is mounted above an aluminum windmill and shines on a smartphone below the windmill
Figure 18. Position your phone underneath the aluminum strip so that it blocks your phone's light sensor every time it passes above. Note: In this image the flashlight was mounted on a stand to hold it above the light sensor. You can also hold the flashlight with your hands.
  1. Open the Science Journal app, start a new experiment, and choose the light intensity sensor. Make sure to label each recording appropriately such as "1 candle", "2 candles", et cetera.
  2. Now its time to light the candles! Have an adult help you light one of the candles.
  3. Wait for 3 minutes.
    1. Waiting will let the heat from the flame build up and ensures that the blades are moving at a constant speed when you start taking your measurements.
  4. Hold a flashlight above your phone's light sensor so that the aluminum strip passes in between your phone and the light. You can either mount your flashlight on a stand (as shown in Figure 18), tape it to a pile of books, or just hold the flashlight with your hands. If you hold it yourself, make sure to keep the flashlight at the same position and as still as possible. Every movement will affect the reading of your light sensor.
  5. Observe the light sensor readings on the display of your phone. It should be relatively constant if you do not move your light source too much. You should notice that every time the aluminum strip passes above the light sensor, a dip occurs on your graph.
  6. Start a new recording for your first experiment by pressing the record button on the app to measure the number of rotations of your carousel. Make sure you hold your flashlight still as long as the app is recording.
  7. After about 1.5 minutes, stop recording and repeat step 8 four more times so that you have done a total of five trials for this number of lit candles.
    1. Make sure that none of the testing conditions change while you perform your different trials. For example, do not move the candle carousel, and make sure the candle flame(s) remain straight and upright the entire time.
  8. Once you have completed all your trials for one lit candle, look at each of your graphs. They should look something like the graph in Figure 19. You can clearly see the drop in light intensity every time the aluminum strip blocked the light from your flashlight which results in a negative peak. Pick a 60 second (or 1 minute) interval of your graph and count the number of negative peaks. Every drop represents one rotation. That means if you count the number of drops, or negative peaks, for one minute, your result will be the number of rotations per minute (rpm). In the example shown in Figure 19, the carousel made 21 rotations per minute.
  9. Repeat counting the rotations per minute for each of your trials and write down your results in the table in your lab notebook.
An example graph measures light intensity from a candle behind a rotating fan blade

An example graph shows light intensity data gathered from a candle that sits behind a rotating fan blade. The majority of the graph is level and lux levels fluxtuate between 720 lux and 1100 lux. The graph also shows numerous and uniform dips in lux values whenever the fan blade rotates and briefly blocks the candle light from reaching the light sensor. The minimum lux value is 9 lux, the average is 871 lux and the maximum is 2,000 lux.

Figure 19. Example data from the Science Journal app. The x-axis of the graph shows time in minute:seconds [min:s] and the y-axis is light intensity in lux. In your graph, choose a 60 second interval to count the number of rotations per minute for your candle carousel.
  1. Repeat steps 4–11 three more times so that you have tested the candle carousel with one, two, three, or four candles lit. Make sure to name each of your recordings respectively.
    1. When you light the second candle, light the one that is at the opposite side from the first candle (so that the lighting is symmetrical). For the third candle, it does not matter which candle you light.

Using a Stopwatch

  1. Make a mark (like a small line) on the edge of one of the carousel's blades. It should be visible enough so that you can easily see it while the blades are spinning around.
  2. Have an adult help you light one of the candles.
  3. Wait for 3 minutes.
    1. Waiting will let the heat from the flame build up and ensures that the blades are moving at a constant speed when you start taking your measurements.
  4. Now count how many rotations the blades make in 30 seconds (sec).
    1. To do this, watch the mark you made (in step 1) and orient yourself so that you can see when it goes directly above one of the candles. Then count how many times the marked blade spins above that candle in 30 sec.
    2. If the blades are not spinning at all, record "0" for the rpm in the data table for this number of lit candles.
  5. Multiply the number of blade rotations in 30 sec by 2 to give you your results in rpm (the number of rotations in one minute, or 60 seconds). Record your answer in your data table.
  6. Repeat steps 4–5 four more times so that you have done a total of five trials for this number of lit candles.
    1. Make sure that none of the testing conditions change while you perform your different trials. For example, do not move the candle carousel, and make sure the candle flame(s) remain straight and upright the entire time.
  7. Repeat steps 2–6 three more times so that you have tested the candle carousel with one, two, three, or four candles lit.
    1. When you light the second candle, light the one that is at the opposite side from the first candle (so that the lighting is symmetrical). For the third candle, it does not matter which candle you light.

Analyzing Your Results

  1. Calculate the average number of rpm for each number of lit candles. Record your results in your data table.
    1. To calculate the average, add up the numbers for each trial and then divide by the number of trials.
  2. Make a line graph of your data, plotting the average rpm versus the number of candles.
    1. Place the number of candles on the x-axis (the horizontal axis) and the rpm of the blades on the y-axis (the vertical axis).
  3. Analyze your results. Look at your data and graph and try to draw some conclusions.
    1. How does lighting more candles appear to affect how fast the candle carousel's blades spin?
    2. Can you explain your results in terms of how the heat from the candles' flames makes the blades spin?
    3. For a more-advanced challenge, see if you can figure out whether the relationship between the number of lit candles and the speed at which the blades are spinning is a linear relationship or if it is non-linear.
      1. If it is a linear relationship, the data points should make a straight line (or a nearly straight line).
      2. Why do you think you see the relationship that you do? What does this tell you about how increasing the amount of heat under the blades affects the blades' rotational speed?

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  • Another factor that could affect how quickly the candle carousel's blades spin is how close the blades are to the flames. You could repeat this science project, but this time test the candle carousel using wooden skewers of different lengths (and keep the number of lit candles constant). (Just be sure none of the skewers are so short that the blades are less than about 5 cm above the flames.) How does changing the distance between the flames and the blades affect the rotational speed of the blades?
  • Changing the angle of the blades could also affect how quickly the candle carousel spins. To test this, use a protractor to carefully bend the blades to different angles (other than 30°, which is what is tested in the original science project idea). When testing a certain angle, have all of the blades bent to the same angle. What is the ideal angle of the blades? In other words, at what angle do the blades spin fastest? At what angles do the blades not spin?
  • How does moving the candles affect the speed of the blades? You could test this by moving all of the candles closer to the skewer, or farther away from it. (You might want to use a stand that gives you more space than the aluminum pan.) When testing a given distance, keep all of the candles the same distance from the skewer.
  • How does friction affect how well the candle carousel spins? To test this, make multiple windmill parts, and for each one try placing a different material within the end of the straw (where it is attached to the pie pan). This will change the friction that the wooden skewer experiences when it is placed in the windmill's straw. What materials work best for making the candle carousel spin? What materials work worst, or cause it to spin the slowest?
  • Can you design a different candle carousel based on the design in this science project? Do some research into different types of candle carousels to get ideas, then try it out! Be sure not to use anything flammable in your design, and only use lit candles with the help of an adult.

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Free science fair projects.