science

Side job

Side job is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Side job rather than just read about it. In short: A side job, also informally called a side hustle (or side gig or side project), is an extra job that a person takes in addition to their primary job in order to supplement their income or simply to turn their hobby into a micro-business. Side jobs may be done out of necessity when a person's main job does not provide sufficient income to support them, or simply out of a desire to earn more money or to try something…

Key takeaways

Side job belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Side job to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Side job from memory before moving on to harder problems.

Reference excerpt

A side job, also informally called a side hustle (or side gig or side project), is an extra job that a person takes in addition to their primary job in order to supplement their income or simply to turn their hobby into a micro-business. Side jobs may be done out of necessity when a person's main job does not provide sufficient income to support them, or simply out of a desire to earn more money or to try something interesting. Working a side job is also referred to as moonlighting, usually when it is performed after regular business hours. A side job can be a full-time job, part-time contract, or freelance work, and a person can hold more than one side job. A "day job" is defined as work a person does "to earn money so that [they] can do something else that [they] prefer but that does not pay [them] much money." Side jobs are typically tasks that can be completed on a part-time or freelance basis at the same time as having a day job. Examples include copywriting, ecommerce (such as selling products on Amazon), affiliate marketing, providing social media marketing services, freelance web design, foreign language lessons or translations, tutoring or coaching, graphic design, freelance writing, and business management. Side jobs have become more prevalent in the United States because of wage stagnation and low wage growth that have not kept up with the rising cost of living. Working a side job imposes a burden since it lengthens one's working hours. In a 2023 survey, nearly 39% of Americans reported having a side job, with 57% of New Yorkers needing one to make ends meet, and a third of U.S. adults said they required a side job to pay for basic household expenses. In the UK in 2019, 60% of students and graduates reported having a side job, and 43% required it to pay renting expenses. The most common reason workers take on side jobs is to obtain additional disposable income. The side job can also be a means to pay off student loans, or to use one's creativity in ways normally not available in the traditional workplace. Millennials were the most likely to have a side job, often to provide a financial "safety net", leading them to be labeled the "side hustle generation". However, Gen Z has surpassed Millennials as the generation with the highest rate of working side jobs. Soham Parekh, a software engineer from Mumbai, became a news story in 2025 for holding so many side jobs with Silicon Valley startups that he was a "serial non-sleeper". He illustrated the grueling lifestyle of a remote worker whose large collection of side jobs comprised a higher paying, albeit unsustainable, substitute for a single primary job.

Companies that began as side projects A number of large companies began as side projects pursued by their founders alongside full-time employment or other primary work.

Nike - Phil Knight sold imported running shoes from the trunk of his car as Blue Ribbon Sports while working as an accountant, and did not leave accounting until the business could support him. Apple - Steve Wozniak designed the Apple I in his spare time while employed at Hewlett-Packard, and Steve Jobs was working at Atari when the two founded the company in 1976. Craigslist - Craig Newmark started the site in 1995 as an email list of local events sent to friends while he worked as a software engineer at Charles Schwab; it operated as a hobby for two years before becoming a company. Twitter - Twitter grew out of an internal side project at the podcasting startup Odeo, developed during a company hackathon in 2006 after Odeo's main product was undercut by Apple. GitHub - The platform was built on nights and weekends by Tom Preston-Werner and co-founders while they held other jobs, before launching publicly in 2008. Slack - Slack began as an internal communication tool built by the team at Tiny Speck while developing the online game Glitch; when the game was shut down, the tool became the company's product. Post-it Note (3M) - The adhesive and the product were developed under 3M's "15 percent time" policy, which allowed researchers to spend part of their working hours on projects of their own choosing. Gmail and Google News - Both products originated under Google's "20 percent time" policy, under which engineers devoted one day a week to projects outside their main assignments. Khan Academy - Salman Khan began recording tutoring videos for his cousins while working as a hedge fund analyst, and left the job in 2009 to run the organization full-time. Minecraft - Markus Persson developed the game in his free time while employed as a programmer, releasing early versions publicly before founding Mojang in 2010

See also Cottage industry Part-time contract Workaholic Freelancer

References

Illustrations

Worked examples

Example 1 — a first encounter with Side job

Start with the simplest possible case. Write down what Side job claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Side job before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Side job ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Side job

In research: Side job appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Side job in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Side job is common in secondary-school and first-year university syllabi. It links to neighbouring topics Employment classifications, Occupations, so understanding it makes those chapters shorter.
In everyday life: Look for Side job outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Side job in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Side job means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Side job out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Side job in simple terms?

Why does Side job matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Side job?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Side job.