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# Paper Clip Chemistry

Heather Haley
Product Developer

Are you looking for inexpensive chemistry activities? Look no further than your office supply cabinet. Paper clips are a great tool to explore a variety of chemistry concepts, including measurement, matter, atomic structure, chemical reactions, and gases.

### Measurement

Classroom objects (such as paper clips) can be used to practice measurement, unit conversions, dimensional analysis, and percent error. Use a ruler (or calipers, if available, for greater accuracy) to measure the length of a paper clip in both inches and centimeters.

Use these measurements to find the unit conversion for inches to centimeters (how many centimeters are in 1 inch) through dimensional analysis. For example, convert from 1 inch to centimeters using the following paper clip measurements:

Further refine your inches to centimeters conversion factor by measuring the length of additional classroom objects (adhesive notes, binder clips, pencils, etc.) in both inches and centimeters. Use dimensional analysis and each object’s measurements to find the unit conversion for inches to centimeters. Find the average of calculated unit conversions and then calculate the percent error. The accepted ratio for inches to centimeters unit conversion is 1":2.54 cm.

The calculated unit conversion for each object may be off, but the average will be very close to 2.54, giving a low percent error.

### Matter

Use groups of colored paper clips to create models of elements, compounds, and mixtures. Each paper clip color represents a different type of atom. Monatomic elements are represented using individual paper clips, whereas diatomic elements are represented using interlocked paper clips of the same color. Use a different color paper clip to represent each element in a compound and link them together. Unlike elements or compounds, mixtures are not constant in composition. Represent them as a combination of both elements and compounds.

Demonstrate how physical properties can be used to separate mixtures of plastic and metal paper clips of various types and sizes.  Plastic paper clips will float in water, and can be separated using density. Metal paper clips contain a small amount of iron, and can be separated using a magnet. A sieve can be used to separate large and small paper clips.

### Atomic structure

Show the law of conservation of mass using large and small paper clips. Without counting, obtain a sample of small and large paper clips. Use a balance to find the mass of small paper clips and record it. Next, use a balance to find the mass of large paper clips and record it. Connect 1 small and 1 large paper clip. Continue connecting 1 large and 1 small paper clip until 1 size of the paper clips is used up. Find the mass of combined paper clips and record it. Find the mass of any remaining large or small paper clips and record it. The total mass of paper clips before combining is the same as the total mass of combined paper clips and remaining paper clips.

Large and small paper clips can also be used to show the law of definite proportions. The procedure is almost exactly the same as the one used for law of conservation of mass, except you perform 3 trials. In the first trial, use approximately the same number of large and small paper clips. In the second trial, use more large paper clips and fewer small paper clips. In the third trial, use fewer large paper clips and more small paper clips. The connected large and small paper clips (Lg and Sm) are synonymous to a compound composed of elements (Lg and Sm). Regardless of the size or source of elements, a given compound is always composed of the same proportion of elements.

To demonstrate the law of multiple proportions, use the same procedure as the law of definite proportions—except you will connect an additional small paper clip to each combined paper clip to form a new compound (LgSm2) and record its mass for each trial.

The tables below can be used to record masses and provide a framework for relevant calculations.

#### Table 4   Calculations—law of multiple proportions.

Use paper clips and envelopes to simulate Milliken’s oil drop experiment to measure the charge of a single electron. Prepare at least 30 sealed envelopes containing a random number of identical paper clips (keep the number of paper clips in each envelope to less than 10). Use a balance to find the mass of each envelope and record it on a piece of paper. Arrange the masses in order from least to greatest. Group similar masses together and find the average for each group. Find the difference in mass between each group. Average the differences between each group and compare with the mass of a single paper clip. The 2 masses should be approximately equal.

#### Related items

To learn how you can use paper clips to teach students about chemical reactions and gases, stay tuned for the next edition of Carolina Tips®.

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