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The Origins of the Periodic Table

It's Elemental

Contrary to schoolyard rumors, no one created the periodic table just to torture you—it all started with the elements. As early as 330 BCE, Aristotle created a four-element table: earth, air, fire, and water. (We'd sign up for a test on that periodic table, no problem.) But it wasn't until the late 1700s that Antoine Lavoisier wrote the first list of 33 elements. He classified them as metals and nonmetals, though we now know that some were compounds or mixtures. Other chemists found 63 elements through the mid-1800s, including their properties and compounds, and during that time, scientists also started noticing unexpected patterns in the properties.

For example, Johann Dobereiner discovered that the atomic weight of strontium fell exactly between the weights of calcium and barium, and all three had similar properties. From this, he created the Law of Triads, which said that in triads of elements, the properties of the middle element would be the average of the other two, if you ordered the elements by atomic weight.

When other scientists tested the theory, they basically found that the triads weren't really triads but parts of larger groups. (For instance, fluorine was added to the halogen "triad.") The main drag on their research was inaccurate measuring tools—if you're trying to order the elements by weight to figure out their relationships, it would have helped to know the correct values.

Shoddy measuring tools didn't stop progress, though. Enter French geologist A.E. Beguyer de Chancourtois, who lined up the elements on a cylinder in order of increasing atomic weight. By stacking the closely related elements, he noticed that their properties repeated every seven elements. The chart had one major flaw: it included ions and compounds as well as elements. A year later (in 1864), John Newlands created the Law of Octaves. Newlands noticed the same pattern that de Chancourtois did—repetition within columns. He also arranged the elements in order of atomic weight and observed similarities between the first and ninth elements, third and eleventh, etc. Much like de Chancourtois, Newlands had one major oversight in his table: he didn't leave any spaces for elements that hadn't been discovered yet.

Symbol Minded

Five years later, we got not one, but the first two, full-fledged periodic tables. Working independently, Lothar Meyer and Dmitri Mendeleev both developed periodic tables. Meyer had published a textbook in 1864 that included an abbreviated version of a periodic table, demonstrating periodic changes in relation to atomic weight. He completed an extended table in 1868 and gave it to a colleague—who obviously took a bit too long to review it. During the review time, Mendeleev's table was published (1869), and Meyer's didn't appear until the next year.

To be fair, Mendeleev's thought process also appears to have been a little bit different than Meyer's. After noticing several patterns, he decided to create a card for each of the 63 known elements that would include the symbol, atomic weight, and chemical and physical properties. He arranged the cards on a table in order of atomic weight and grouped elements with similar properties. The table ended up showing not only group relationships, but vertical, horizontal, and diagonal relationships as well. (Alas, poor Mendeleev came only one vote away from being awarded the 1906 Nobel Prize for his work.) Unlike Meyers, Mendeleev was able to use the gaps in his table to make predictions about yet-to-be-discovered elements, and remarkably, many turned out to be true.

[See Also: Name the Noble Gases in 1 Minute]

This article was written by Liz Hunt and excerpted from the mental_floss book In the Beginning: The Origins of Everything. You can pick up a copy in our store. Also available in our store is the Periodic Table shower curtain.

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5 Subtle Cues That Can Tell You About Your Date's Financial Personality
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Being financially compatible with your partner is important, especially as a relationship grows. Fortunately, there are ways you can learn about your partner’s financial personality in a relationship’s early stages without seeing their bank statement or sitting them down for “the money talk.”

Are they a spender or a saver? Are they cautious with money? These habits can be learned through basic observations or casual questions that don’t feel intrusive. Here are some subtle things that can tell you about your date’s financial personality.

1. HOW THEY ANSWER BASIC MONEY QUESTIONS.

Casual conversations about finance-related topics can be very revealing. Does your date know if their employer matches their 401(k) plan contributions? Do you find their answers to any financial questions a bit vague—even the straightforward ones like “What are the rewards like on your credit card?” This could mean that your partner is a little fuzzy on some of the details of their financial situation.

As your connection grows, money talks are only natural. If your date expresses uncertainty about their monthly budget, it may be an indicator that they are still working on the best way to manage their finances or don’t keep close tabs on their spending habits.

2. WHAT THEY’RE WATCHING AND READING.

If you notice your partner is always watching business news channels, thumbing through newspapers, or checking share prices on their phone, they are clearly keeping abreast of what’s going on in the financial world. Ideally, this would lead to a well-informed financial personality that gives way to smart investments and overall monetary responsibility.

If you see that your date has an interest in national and global finances, ask them questions about what they’ve learned. The answers will tell you what type of financial mindset to expect from you partner moving forward. You might also learn something new about the world of finance and business!

3. WHERE THEY GET THEIR FOOD.

You may be able to learn a lot about someone’s financial personality just by asking what they usually do for dinner. If your date dines out a lot, it could be an indication that they are willing to spend money on experiences. On the other hand, if they’re eating most of their meals at home or prepping meals for the entire week to cut their food budget, they might be more of a saver.

4. WHETHER THEY’RE VOICING MONEY CONCERNS.

Money is a source of stress for most people, so it’s important to observe if financial anxiety plays a prominent role in your date’s day-to-day life. There are a number of common financial worries we all share—rising insurance rates, unexpected car repairs, rent increases—but there are also more specific and individualized concerns. Listen to how your date talks about money and pick up on whether their stress is grounded in worries we all have or if they have a more specific reason for concern.

In both instances, it’s important to be supportive and helpful where you can. If your partner is feeling nervous about money, they’ll likely be much more cautious about what they’re spending, which can be a good thing. But it can also stop them from making necessary purchases or looking into investments that might actually benefit them in the future. As a partner, you can help out by minimizing their expenses for things like nights out and gifts in favor of less expensive outings or homemade gifts to leave more of their budget available for necessities.

5. HOW THEY HANDLE THE BILL.

Does your date actually look at how much they’re spending before handing their credit card to the waiter or bartender at the end of the night? It’s a subtle sign, but someone who looks over a bill is likely much more observant about what they spend than someone who just blindly hands cards or cash over once they get the tab.

Knowing what you spend every month—even on smaller purchases like drinks or dinner—is key when you’re staying on a budget. It’s that awareness that allows people to adjust their monthly budget and calculate what their new balance will be once the waiter hands over the check. Someone who knows exactly what they’re spending on the small purchases is probably keeping a close eye on the bigger picture as well.

REMEMBER THERE’S NO SUBSTITUTE FOR TALKING.

While these subtle cues can be helpful signposts when you’re trying to get an idea of your date’s financial personality, none are perfect indicators that will be accurate every time. Our financial personalities are rarely cut and dry—most of us probably display some behaviors that would paint us as savers while also showing habits that exclaim “spender!” By relying too heavily on any one indicator, we might not get an accurate impression of our date.

Instead, as you get to know a new partner, the best way to learn about their financial personality is by having a straightforward and honest talk with them. You’ll learn more by listening and asking questions than you ever could by observing small behaviors.

Whatever your financial personality is, it pays to keep an eye on your credit score. Discover offers a Free Credit Scorecard, and checking it won't impact your score. It's totally free, even if you aren't a Discover customer. Check yours in seconds. Terms apply. Visit Discover to learn more.

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Animals
Where Do Birds Get Their Songs?
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Birds display some of the most impressive vocal abilities in the animal kingdom. They can be heard across great distances, mimic human speech, and even sing using distinct dialects and syntax. The most complex songs take some practice to learn, but as TED-Ed explains, the urge to sing is woven into songbirds' DNA.

Like humans, baby birds learn to communicate from their parents. Adult zebra finches will even speak in the equivalent of "baby talk" when teaching chicks their songs. After hearing the same expressions repeated so many times and trying them out firsthand, the offspring are able to use the same songs as adults.

But nurture isn't the only factor driving this behavior. Even when they grow up without any parents teaching them how to vocalize, birds will start singing on their own. These innate songs are less refined than the ones that are taught, but when they're passed down through multiple generations and shaped over time, they start to sound similar to the learned songs sung by other members of their species.

This suggests that the drive to sing as well as the specific structures of the songs themselves have been ingrained in the animals' genetic code by evolution. You can watch the full story from TED-Ed below, then head over here for a sample of the diverse songs produced by birds.

[h/t TED-Ed]

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