Will we ever be able to shrink and grow stuff?


It would be fun to be able to shrink people and objects, but it’s something we can only imagine. Jasmin Merdan/Moment via Getty Images

Salvatore Rappoccio, University at Buffalo, The State University of New York

 

Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to curiouskidsus@theconversation.com.


Will we ever be able to shrink and grow stuff? – Luke, Brookline, Massachusetts


Maybe you’ve seen “Ant Man” or “Avengers: Endgame,” where people can grow to the size of buildings or shrink down to the “Quantum Realm” and travel through time.

This sounds fun, but unfortunately it can’t happen in real life. To see why, let’s look at how things are put together.

Everything we know of in the universe is made of the same things: atoms. They work similarly to Tinkertoys, where blocks are connected by rods to make things.

A cartoon of atoms arranged in a cube, zoomed in 20 million times. Cadmium/Wikimedia

The simplest forms objects take are crystals. You see crystals in your life all the time, from table salt to metals. These crystals are bunches of atoms connected in repeating shapes, like cubes or hexagons.

An actual image of a crystal in a hexagonal pattern, taken with a very powerful microscope called a scanning tunneling microscope. Guillaume Baffou/Wikimedia, CC BY-SA

If you wanted to grow or shrink something like a crystal, an ant or a person, you’d need to change the distance between the atoms. To shrink something, the distance must get smaller. To grow something, the distance must get larger.

The problem is that the rods connecting the atoms really act like tiny springs: they don’t want to be pushed together, or pulled apart. They want to stay at the same length. This length is so tiny that you could fit a thousand of them inside the width of a single human hair.

Atoms don’t like to be too close or too far apart. Viviana Rappoccio, CC BY-ND

How much these tiny springs resist pushing or pulling is determined by the electric force, which is a constant of nature. As far as scientists know, the electric force has the same strength everywhere in the universe, for all time. To grow or shrink something, we would have to change the strength of the electric force, which is not possible to the best of our knowledge.

There are a few things in the world that do shrink or grow, but the way they do so is not by shrinking or growing at the atomic level. Usually it involves adding or removing water or something else. Grapes shrink into raisins when they lose water, and sponges expand when they soak up water.

Many cultures throughout history have removed water from the bodies of people who have died, which is how mummies are made. However, they don’t really shrink all that much. There are also ways to grow or shrink microscopic things like nano-structures by pushing or pulling their atoms together a little bit, but we can’t do the same thing to people, or ants. Sorry, “Ant-thony.”


Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to CuriousKidsUS@theconversation.com. Please tell us your name, age and the city where you live.

And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.The Conversation

Salvatore Rappoccio, Associate Professor of Physics, University at Buffalo, The State University of New York

This article is republished from The Conversation under a Creative Commons license. Read the original article.