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How Compasses Work

Interactive passage with audio narration, comprehension questions, and printable PDF.

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Format: Interactive (Online), Printable (PDF)
Grades: 5678
Subjects: scienceela
Standards: MS-ESS2-1
Languages: English, Spanish

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What's included

Reading passage

Reading comprehension

Audio narration

With word word highlighting

Comprehension quiz

Auto-graded

Writing activity

Open-ended response

Glossary & flashcards

Vocabulary practice

Differentiated version

Adapted for varied levels

Spanish translation

Bilingual support

About this reader

This engaging 400-500 word science passage explains how compasses work for middle school students in grades 6-8. Aligned with NGSS standards MS-ESS2-1 and MS-ESS2.A, the passage explores how a magnetized needle inside a compass interacts with Earth's magnetic field to point toward magnetic north. Students learn that a compass is simply a small magnet responding to Earth's enormous magnetic field generated by the geodynamo. The passage includes real-world examples of compass use in navigation and connects to broader Earth systems concepts. Audio-integrated for accessibility, this resource includes a simplified version for English Language Learners, Spanish translations, a comprehensive glossary of key terms, multiple-choice questions, writing activities, and graphic organizers. Perfect for teaching Earth's magnetic field and navigation tools in middle school science classrooms.

Written by Workybooks TeamPublished by Workybooks

Sample passage and quiz content

CONTENT PREVIEW

A black and white photo of a man holding a compass during a forest exploration, symbolizing navigation. — Inside every compass is a small, lightweight magnetized needle that can spin freely on a pivot. Image by Сослан / Pexels.

How does a simple compass always seem to know which way is north? The answer lies in a clever interaction between two magnets. Inside every compass is a small, lightweight magnetized needle that can spin freely on a pivot. This needle is itself a tiny magnet with its own north and south poles. Because Earth acts like a giant magnet with its own magnetic field, the compass needle responds by lining up with that field.

The process is straightforward. Earth's magnetic field extends from the planet's core out into space, creating invisible lines of force. When you hold a compass, the magnetized needle inside experiences a force from Earth's magnetic field. One end of the needle is attracted toward Earth's magnetic north pole, while the other end points toward the magnetic south pole. The needle rotates until it aligns with Earth's magnetic field lines. This alignment happens because magnets naturally orient themselves along magnetic field lines, just as two bar magnets will turn to attract each other.

The compass isn't doing anything fancy or mysterious. It's simply a small magnet responding to the enormous magnet that is our planet. Earth's magnetic field is generated by the geodynamo, a process involving the movement of molten iron in Earth's outer core. This creates a magnetic field strong enough to affect compass needles thousands of miles away on the surface. Scientists explain that the compass needle acts as an indicator of the direction of Earth's magnetic field at any location.

Compasses have been used for navigation for over a thousand years. Chinese sailors used magnetic compasses as early as the 11th century to guide ships across open water. Today, hikers, explorers, and surveyors still rely on compasses, even with modern GPS technology available. A compass works anywhere on Earth without batteries or signals. Evidence shows that many animals, including sea turtles and migratory birds, can sense Earth's magnetic field and use it for navigation, much like a built-in biological compass.

Understanding how compasses work reveals something important about our planet. Earth's magnetic field not only helps us find direction but also protects us from harmful solar radiation. The magnetic field deflects charged particles from the sun, creating a shield around our planet. A simple compass demonstrates this invisible but powerful force in action, turning an abstract concept into something you can hold in your hand and observe directly.

Interesting Fact: Earth's magnetic north pole is not fixed in one place. It actually moves about 25 to 40 miles per year due to changes in the flow of molten iron deep inside Earth's core.

What is inside a compass that allows it to point north?

A battery-powered motorA magnetized needleA GPS receiverA spinning wheel

Why does the compass needle align with Earth's magnetic field?

Because it is powered by electricityBecause it is connected to satellitesBecause magnets naturally orient themselves along magnetic field linesBecause it is programmed with directions

What does the term 'geodynamo' refer to?

A type of compass used by sailorsThe movement of molten iron in Earth's outer core that creates the magnetic fieldA device that measures magnetic strengthThe rotation of Earth on its axis

In the passage, what does 'aligns' mean?

Spins rapidly in circlesLines up or arranges in a straight line with something elseBreaks apart into piecesChanges color

Based on the passage, why do hikers still use compasses even though GPS technology is available?

Compasses are more accurate than GPSCompasses work anywhere on Earth without batteries or signalsGPS devices are illegal in wilderness areasCompasses are cheaper to buy

Which animals are mentioned in the passage as being able to sense Earth's magnetic field?

Dogs and catsSea turtles and migratory birdsFish and dolphinsBears and wolves

What is one important function of Earth's magnetic field besides helping with navigation?

It creates weather patternsIt protects us from harmful solar radiationIt makes compasses workIt causes earthquakes

According to the passage, when did Chinese sailors first use magnetic compasses?

In the 5th centuryIn the 11th centuryIn the 15th centuryIn the 20th century

True or False: Earth's magnetic north pole stays in exactly the same location all the time.

TrueFalse

True or False: A compass needle is itself a small magnet with north and south poles.

TrueFalse