Ten Hundred Word Challenge: Elizabeth Measures Pesticides in Food

Every now and again scientists need to show their silly side. This April Fools weekend we’re launching the Ten Hundred Word Challenge at Chembites! (We’re not sure if the joke is on you, or on us.)

With only the 1,000 (aka “ten hundred”) most commonly used words, our Chembiters might feel like fools as they explain science without the familiar comfort of the jargon only some people understand. The results can be funny, long-winded, or downright frustrating! Hang with us while we give this challenge a shot. And many thanks to xkcd for inspiring people to take on this challenge, and to Science Buffs for keeping the challenge alive!

Setting a brave example, the chair of our Chembites team, Elizabeth Lam, explains her research quantifying pesticides in food. She starts with a “simplified” version using only the 1,000 most commonly used words, then re-writes an “unsimplified” version that relaxes the jargon rule.

Elizabeth Lam: Is It Safe to Eat?


We want to have nice food, and we do not want our food to be eaten by flies. It is the same for people growing food. They do not want tiny animals or flies to eat our food before we have it. So they add something that makes flies sick, and the flies go away.

However, these added things not only scare flies, but can also hurt us! So, people have been finding ways to keep an eye on how much of these things are left in our food when we have our dinner.

First we have to know what these things are. People study them by breaking them down into smaller pieces. The broken pieces point to what the larger things are. It is like how everyone has their own family tree. When you know the sons and daughters of a person, you can follow the lines that point back to that person to find out who he is.

This way of following the lines of broken pieces to study the whole thing is great. However, because the food under study may also have broken pieces that look like the things that hurt flies, people need to clean the food to take out only what they want to study. Then they can look at the broken pieces of just the thing that hurts flies.

So how do we do that? Think of a bag of large red balls and small green balls. You know each ball has a different name and how heavy they are, but you do not know which is which, and you only want to pick one of the large red balls. This large red ball is the thing you want to study. So you use a bag with a small opening to let the green balls pass through first. Then you sort the red balls from the lightest to the heaviest. You can then match how heavy they are with their names and find your pick.

So now we know what is inside our food and can make sure the food is safe before you enjoy your nice food!



We all want to have a nice tasty meal, but insects and flies compete with us for food! Farmers do not want their crops to be stolen by insects or pests, so they spray chemicals, called pesticides, onto their crops. Pesticides prevent pests from eating all the crops by killing them before they can chow down.

However, while these pesticides hurt pests, they may also be harmful to people! So, chemists have to watch out for the pesticide levels in the crops before they come to our plates!

Chemists use a technique called mass spectrometry to identify the thousands of pesticides existing in the world. With mass spectrometry, the pesticide compounds are broken down into smaller fragments. By identifying these fragments and measuring their concentrations, chemists can trace them back to the original chemical compound. It is like tracing an ancestor within a family tree. Through the sons and daughters, you can trace back to their parents, and eventually connect the dots back to their ancestor.

Identifying a compound through mass spectrometry is an amazing technique that is now commonly used in laboratories. However, other substances in food, such as proteins and fats, can interfere with pesticides identification and lower detection accuracy.  Therefore, chemists have to separate pesticides from food before running mass spectrometry.

So how do chemists separate pesticides from food? Imagine a bag of large red balls and small green balls, each with a unique name. The green balls represent compounds like proteins or fats while the red balls represent pesticides. Your goal is to separate one of the large red balls (a pesticide you want to study) from all the others. So you pour all the balls through a sieve, and the green balls pass through while the red ones don’t. Then, you line up the red balls by weight. You can then match how heavy they are with their names and find your target..

Chemists use these separation and identification techniques together and call it gas chromatography/mass spectroscopy or liquid chromatography/mass spectroscopy, depending on the medium used (gas or liquid). These common practices are not only used to identify, but also quantify the level of pesticides in our food.

Pesticides are like a double-edged sword. If we use them properly they help secure our food supply. Yet, if we use pesticides excessively we could harm ourselves. Thanks to chemists who are constantly finding new methods to detect and quantify the pesticides in our food, we can now enjoy safe and delicious meals at the table!

By Elizabeth Lam

Thanks for bearing with us for Chembites first Ten Hundred Word Challenge! Check back next week as chembiter Charlie Crowe takes on the challenge for his research on simulating chemical reactions that occur in our cells.

Want to try the challenge for yourself? Use this text editor to find out if the words you choose are allowed or not!