Make a DIY spinning top from a CD and a marble
A recycled CD, a marble and a small amount of adhesive can become a simple physics investigation for a classroom, homeschool setting or rainy-day activity. As the disc rotates, learners can observe balance, friction, gravity, rotational inertia and the gradual loss of energy.
This project suits Australian students because it uses inexpensive materials that are easy to find at a supermarket, craft shop or resource cupboard. It can be adapted for a primary classroom in Brisbane, a homeschool table in regional Victoria or a STEM session before heading out to the school oval.
Materials and preparation
You will need one unwanted CD or DVD, one round marble, removable adhesive such as Blu Tack, strong craft glue or double-sided tape, a ruler, a pencil, a stopwatch and a smooth, level surface. A marker and coloured paper can add a creative element, while safety scissors are useful if students decorate the disc with paper shapes.
Inspect the disc before beginning. Do not use one with sharp cracks, and remind children that a marble can be a choking hazard for young learners. If using permanent glue, an adult should attach the marble. Blu Tack is a practical choice for a temporary demonstration because the activity can be adjusted and repeated without damaging the CD.
Clean the disc so dust does not interfere with its movement. The central hole should be clear enough for the marble to sit beneath it. If the opening is too wide, place a small ring of cardboard around the top of the hole to help centre the marble.
Building the spinning top
Turn the CD label-side up and place the marble directly beneath the centre hole. From the upper side, add small, evenly spaced pieces of adhesive around the opening so the marble is held firmly against the underside. The marble should project below the disc like a rounded axle, while the CD remains flat and balanced.
Press gently around the centre rather than pushing down on one edge. Test the spinner by placing the marble on a smooth desk and giving the disc a light twist. If it wobbles sharply, reposition the marble or adjust the adhesive. A symmetrical design is important because uneven mass makes the centre of gravity move away from the axis of rotation.
Students can decorate the CD with coloured sectors, spirals or repeating patterns. When the disc turns quickly, colours may appear to blend because the eye retains an image for a short time. This gives the craft a visual connection to optical illusions while keeping the main investigation focused on motion.
What the movement reveals
A spinning top stays upright because its rotating disc resists a sudden change in the direction of its axis. This property is called angular momentum. Gravity pulls the disc down, but the rapid rotation helps it remain stable for a while. As the spin slows, the top begins to wobble and eventually falls.
Friction acts in several places. The marble rubs against the desk, air pushes against the disc and the adhesive may flex slightly. These forces convert some of the spinner’s movement into heat and sound. A smoother tabletop usually produces a longer spin, while a rough surface such as a classroom carpet brings it to rest quickly.
| Design choice | Likely effect | Physics idea to discuss |
|---|---|---|
| Smooth desk | Longer, steadier rotation | Reduced friction |
| Carpet or rubber mat | Faster slowing and more wobble | Increased friction |
| Marble centred carefully | Balanced movement | Centre of mass |
| Heavy decoration on one side | Uneven or tilted spin | Mass distribution |
| Larger, faster initial twist | More rotation time | Angular momentum |
Ask students to predict which surface will produce the longest run before testing it. They can record three trials for each surface, calculate an average time and compare the results. This connects naturally with classroom data work; for another hands-on activity involving chance and recording results, teachers can explore probability games.
Turning the activity into a maths lesson
The spinner can become a practical way to collect measurements. Students might compare a gentle push with a strong push, test different CD decorations or investigate whether a marble, wooden bead or metal washer changes the spin. Older learners can create a results table with trial number, surface, spin duration and observations about wobbling.
The activity also supports Australian Curriculum links in Science and Mathematics. Learners can identify forces, make predictions, measure elapsed time and represent results in a column graph. In Australian classrooms, using the term “maths” and connecting the investigation to a familiar school oval, library table or covered outdoor learning area can make the lesson feel immediate and accessible.
For a literacy extension, students can write a short procedural text using precise verbs such as “centre”, “secure”, “rotate” and “measure”. They can also explain why a balanced spinner performs better than one with decorations clustered on a single side. A simple design journal works well for mixed-age groups and allows younger children to draw observations instead of writing full explanations.
Extending the investigation safely
Try adding a second CD to make the spinner wider, but discuss whether the extra mass changes the time needed to start it moving. Another variation uses a paper template divided into equal sections. Students can predict how the pattern will look while stationary and then describe what changes during rotation. Educators seeking additional visual activity ideas can also browse hands-on learning ideas when planning a broader craft and science session.
Safety remains straightforward. Keep fingers away from the spinning edge, use only intact discs and avoid launching the marble across a room. On a hot Australian afternoon, work indoors on a sturdy table rather than on a windy verandah, since air movement can affect the disc and distract from the results. Store spare marbles in a sealed container, particularly where younger children or pets are present.
The finished CD spinner is inexpensive, reusable and easy to adapt. It gives students a visible way to explore forces that are otherwise difficult to see, while combining making, measuring, discussion and creative design in one compact physics activity.