Introduction: A Balance Scale and Graduated Cylinder for Measuring Density

I designed this project to find the density in common items. I built both tools using household items like string, tape, and plastic.

To create a similar balance scale, find some string, scissors, two plastic cups, and one clothes hanger. I chose these materials because they can hold items, are strong, and do not break often. I designed the balance scale this way because it is easy to set up and is very accurate. Inspiration from this design are images from

I built this balance scale in multiple steps. I will list them all.

1. Cut two pieces of one and a half foot string.

2. Poke two holes in each plastic cup using a sharp pin or pencil tip.

3. Bring the string through the holes in the cups.

4. Tie both strings to the clothes hanger and tie a knot.

5. That's it! Your design should similar to the images above.

I tested my balance scale by putting in objects similar in weight. I put in a tablespoon of salt and six paper clips, which are pretty equivalent in weight. The cups were basically balanced! Based on my tests, my balance scale is very accurate and will be incredibly useful in the future.

To make an almost identical graduated cylinder, you will need a one liter soda bottle, a piece of paper, a pen or pencil, a ruler that marks millimetres, some tape, scissors, and a knife. I chose these materials because they are strong and reliable. Again, inspiration came from

This is the steps I took in building the graduated cylinder:

1. Cut the neck of the soda bottle.

2. Take the piece of paper and cut it to make a square.

3. Take the ruler and mark every millimetre there is.

4. Tape the paper on the soda bottle.

I tested the graduated cylinder by filling it up with water, putting an item in there, and then marking how far the water level went up in millimetres. My graduated cylinder was effective, but I'm still trying to make it more effective.

Density is the amount of matter in any given space. To find density, simply find a objects mass and volume. Density is mass divided by volume. I found the density of these objects in relationship to each other.

1. Golf Ball vs. Ping pong ball

Golf Ball mass: more or less? More

Golf Ball volume: more or less? Same

Golf Ball density: more or less? More

Ping Pong Ball mass: less

Ping Pong Ball volume: same

Ping Pong Ball density: less

2. Battery AAA vs. Foam Poke ball

Battery mass: more

Battery volume: less

Battery density: more

Poke ball mass: less

Poke ball volume: more

Poke ball density: less.

And that is how I created a homemade balance scale and graduated cylinder!