Math Clocks
& Other Interesting Clocks

Our math clocks have been selected by
the New Scientist magazine in London for its holiday gift guide
and the Museum of Mathematics in New York for its museum shop.
 

Note: Clicking on a picture of a clock
opens a new window containing a larger
picture of that clock, so that you can
see it and read about it simultaneously.
 

Purchasing & General
information below
 

The Math Clock – Student Edition & Engineers Edition

In place of the standard numbers 1 to 12, this clock displays an interesting assortment of expressions from many different areas of curriculum and recreational mathematics, which of course evaluate to the numbers 1 to 12. The student edition comes with a small green card that provides a couple of conceptual words for each expression – to facilitate the student looking up the concepts on the Internet. The engineers edition is labeled as such, so is appropriate for non-students.

The Math Clock – Professional Edition

A more advanced version of the previous clock, this is our flagship product! The most advanced expressions involve calculus and number theory. (No hint card is included but our email address is on the back in case you have any questions!)

The Math Clock – Radian Edition

In polar coordinates, angles are measured clockwise from the positive x-axis. Thus, this clock starts at midnight with both hands pointing to what is normally the 3 o'clock position – and then from there it goes backwards!
A full circle is 2π radians, so each hour is 2π /12 = π / 6 radians. To facilitate time-telling, the unreduced terms' numerators, which indicate the hours, are written in green.
The squiggly second hand represents a sine wave.

The Math Clock – Radian Edition – Version Tau

This clock has all the special features of the previous clock: direction of motion; orientation of hours; sinusoidal second hand; and green cheat marks.
However, here the radian measures are expressed in terms of τ, the true circle constant, rather than π. (See TheTau Manifesto.) A full circle is τ radians, so each hour is τ /12 radians. The central image includes a Tao symbol. Designed on Tau Day, 2011.

The Math Clock – Prime Edition

Prime numbers are printed in red. For composite numbers, their prime decomposition is shown. Since the number 1 is neither prime nor composite, which is an important and often-misunderstood fact, it is printed specially, as an outline. The second hand is red.

The Math Clock – Primorial Edition

With the same color scheme as the previous clock, this advanced version uses several different concepts from prime number theory – prime counting functions, twin primes, Mersenne primes, Lucas primes, Fermat primes and primorial primes.

The Math Clock –
Pi Edition

This clock was created especially for Pi Day but it works just as well the rest of the year. The expressions involve many different uses of π as a mathematical symbol, not just for the well-known transcendental number but for more obscure ideas in branches of mathematics from number theory to algebraic topology.
(Thus, this is a perfect horizon-expanding gift for those geeks who have been wasting their extra brain cells competing to memorize the longest sequence of digits constituting 0% of π's decimal expansion!)
The colorful design in the center is, of course, a pie chart.

The Math Clock –
Sets Edition

The colorful design in the center of this clock is a Venn diagram that makes use of the subtractive colors of computer graphics. Thus the main sets are the primary RGB colors, their binary intersections are the corresponding secondary CMY colors, and the intersection of all of them is white.
The 12 elements of this universe are placed to simultaneously maximize aesthetics and pedagogy, illustrating many different elementary set theory concepts (unions, intersections, complements, set differences, symmetric differences, combining set operations, and cardinality).

The Math Clock –
Figurate Edition

The n^th hour is represented by the n^th triangular number, the n^th square number and the n^th centered hexagonal number. To easily distinguish them, each type of figurate number is colored to match the corresponding figure in the center.
Also included in the central picture are recurrence relations, closed-form expressions, and relationships between the three different sequences

The Math Clock –
1-2-3 Edition

In our newest clock, the expression for each hour is composed of the numerals 1,2 and 3, in that order. No other numbers, just operators and functions, are used.

The central picture shows a 30°-60°-90° triangle, because of its irrespective but mnemonic side length ratios of "one, two, root three".

The Math Clock –
Recursive Edition

Whether you start reading the circular saying at the top or bottom of the clock, the circular meaning is the same.
The text is colored in spectral order, somewhat like a double rainbow.
The successor function, an important primitive recursive function, is applied to 1 n-1 times for the n^th hour.

The Math Clock – Fibonacci Sequence

In this clock, the hours are represented by the corresponding number in the famous Fibonacci sequence, which is 1,1,2,3,5,8,... The n^th term in the sequence, F_n, represents hour n on the clock.
The rabbit motif highlights the well-known origin of the Fibonacci sequence as a rabbit population model. The design is based on an ancient puzzle called the three hares. (It's a simple Sam Lloyd type puzzle: how many ears are there if each of the 3 hares has 2 ears?)
The hour and minute hands are shaped like rabbit ears.

The Math Clock – Fibonacci Formula

See the previous clock's description regarding the design in the center and the clock hands. In this variation, the hours are represented by arithmetic expressions involving the terms of the Fibonacci sequence (i.e. F₁=1, F₂=1, F₃=2, F₄=3, F₅=5, etc.) Students who are unfamiliar with the Fibonacci sequence can actually derive it by using simple algebra to combine the expressions and solve for the terms, and then deduce the pattern.

The Math Clock – Binary Edition

This clock, a more colorful and more durable version of our binary CD clock, was created to coordinate with our binary wrapping paper. The numerals are a neon-like green, reminiscent of antediluvian computer screens, 'though not as bright as the paper or t-shirt. The text in the center is written in ASCII code and is as descriptive as that of the wrapping paper. Note that this clock does not have a second hand – after all, there are already too many digits in binary times!

The Math Clock – Hex Edition

This is the same as the previous clock (despite the poor photo qualty) except that it uses base 16 instead of base 2, with a typical computer programming language notation for hexadecimal numbers, and it has a barely visible black second hand.

The Chemistry Clock

The hours are represented by the atomic numbers of elements, namely the first 12 elements of the periodic table. Different background colors correspond to different kinds of elements, such as alkali metals and noble gases. A colorful key on the back of the clock explains the types of elements as well as all the other symbols from the periodic table.
The canonical image of electron rings in the center matches the hours chromatically and the clock hands thematically.

T-Time –
The Ortho Clock & the Chiro Clock

This is our first personalized clock. The name of the doctor or the practice is written along circular arcs in the center.
Its design was inspired by an accident; at the doctor's office, we learned that humans have exactly 12 thoracic vertebrae, and they're called T1 through T12.
The n^th hour is represented by a superior view of the n^th thoracic vertebra, with the label Tn. And the ornate clock hands complement these graphics.
(As with our Student/Engineer editions, the Ortho/Chiro editions are distinguished on the labels.)

The Dental Clock

Our second personalized clock was created to make a small dent in our huge dental bills. The name of the doctor or the practice is written along circular arcs in the center. The n^th hour is represented by a facial (i.e. buccal or labial) view of permanent tooth #n (according to the ADA's Universal Numbering System, starting with the furthest back upper right molar). The hour and minute hands are evocative and the second hand is playful.
.

The Music Clock

This geometric arrangement known as the Circle of Fifths is perfect for a clock!
The hours are represented by the # (i.e. number) of #s (i.e. sharps) in the key signature. (Note that when no sharps appear, the number of sharps equals 12 minus the number of flats.)
The label on the back explains how the design is used for composing Western music and also lists the 12 major and corresponding minor keys.
And the highly ornate hands complement the treble clefs.

The
Carb Clock

Each hour is represented by a cross-section of a piece of fruit that has that number of grams of carbohydrate per piece, to the nearest gram. For example, an avocado contains only 2 grams of carbs! (Note that the amount can vary depending on the size of the piece of fruit, so do not rely on this carb counter for your diet.)

The
Hebrew Clock

In Hebrew, the letters of the alphabet have numerical values, which are used to represent the hours on this clock (e.g. alef is 1, yud is 10, yud-alef is 11). The ornate style of the hands matches the calligraphic font.

The
Hebrew Clock – Reverse Version

Since Hebrew is read from right to left, just for fun this clock runs backwards! It looks particularly nice when placed side-by-side with the previous one, as they're then mirror images. Sorry, this clock is currently unavailable. Email to be notified when it becomes available.

The
Hindi Clock

Contrary to popular belief in the West, the Arabs were not the first to use a positional decimal numeral system – they learned it from the Indians (who may have learned it from the Chinese). The numerals on this clock are the Indian ones in their modern Devanagari form.
The clock's coloration and central design reflect those of the flag of India. In fact, the 24 spokes of the Ashoka Chakra represent the 24 hours of the day.

The
Portraits Clock

Our most personalized clock is appropriate as a Bat Mitzvah gift with portraits from the ages 1-12, or a first birthday gift with monthly photos, or a high school graduation gift with portraits from the grades 1-12, or a Mother's Day gift for a woman with 12 grandchildren, or . . . The gold-hued hands feature diamonds and a heart, connoting preciousness and love. Both the wording and the rim color are somewhat customizable.

General description: Each clock is ≈ 10" (25 cm.) in diameter, has metal hands, not plastic, and a U.S.-made I-shaft movement (except for the reverse movements, which are from Asia); and requires one AA battery, not included.

Prices: All clocks cost $40 except for the following:

• the prime and primorial versions, which are priced at P₁₃ ($41) and P₁₄ ($43), respectively
• the Fibonacci versions, which cost F₉ ($34)
• the pi clock, which is priced at  ≈ 14 π dollars ($44)
• the 1-2-3 version, which costs $12x3 ($36)
• the binary clock, which costs $101010₂ ($42),
  and the hex clock, which is only $29₁₆ ($41)
• the Hebrew clock, which is priced at double-chai ($36)
  
• the ones that run backwards, which cost $60
• the personalized business ones, which cost $75 (but are probably tax-deductible)
• the portraits clock, which is priceless (but please inquire anyway!)

California residents must add sales tax.

Shipping Click here for new, fairer shipping cost tables
                 Please note that deliveries outside the U.S. may be subject to customs duties, taxes
                 and/or fees upon arrival; these costs are not included in our product or shipping charges.

Buying a Gift? Mathematical wrapping paper is $4.

To order by check, send to SB Crafts at 6167 La Goleta Road, Santa Barbara, CA 93117.
Be sure to include an email address and/or phone number in case we need to contact you
If you have a PayPal account, you can send the payment to paypal@sbcrafts.net (note: not .com).

For any questions, PayPal assistance, international, wholesale or rush orders,
email info@SBCrafts.net or call (805) 967-2270.