Combined Science57Updated 6 Oct 20264 pages

Density Practice Questions and Detailed Answers

Report
Density is one of the most useful concepts in physics - it helps explain why ice floats, how ships stay afloat, and even how miners identify real gold! Understanding density calculations will give you the tools to solve loads of practical problems in your exams and beyond.
density revision questions and answers – page 1

Sign up to see the content.
It's free!

By signing up you accept Terms of Service and Privacy Policy

Basic Density Calculations

Density is simply how much mass is packed into a given volume - think of it as how "heavy" something feels for its size. The formula is straightforward: density = mass ÷ volume.

When tackling density problems, always start by writing down what you know and what you're looking for. Then convert your units carefully - you'll usually work with either grams and cm³ or kilograms and m³, but stick to one system throughout.

The key trick is remembering your conversions: 1 litre = 1000 ml = 1000 cm³, and 1 kg = 1000 g. Get these right, and the rest becomes much easier.

Quick Tip: Always check your units match before plugging numbers into the formula - mixed units are the biggest source of errors in density calculations!

density revision questions and answers – page 2

Sign up to see the content.
It's free!

By signing up you accept Terms of Service and Privacy Policy

Finding Mass from Density

Sometimes you'll need to find mass instead of density, which means rearranging the formula. Don't panic - it's just basic algebra! If density = mass ÷ volume, then mass = density × volume.

The process stays the same: write down what you know, calculate any missing values (like volume from dimensions), then substitute into your rearranged formula. Remember that volume of a rectangular block is length × width × height.

Always double-check your final answer makes sense. A small wooden block shouldn't weigh 20 kg, and a tennis ball shouldn't have the same density as lead!

Study Smart: Practice rearranging the density formula until it becomes automatic - you'll use this skill in chemistry and other physics topics too.

density revision questions and answers – page 3

Sign up to see the content.
It's free!

By signing up you accept Terms of Service and Privacy Policy

Real-World Applications

Density is brilliant for identifying materials - that's how the miner can tell real gold 19g/cm319 g/cm³ from fool's gold 5g/cm35 g/cm³. Even if the sample isn't perfectly pure, densities that are much closer to the real thing usually indicate authenticity.

Different states of matter have different densities too. Molten iron 7.0g/cm37.0 g/cm³ is less dense than solid iron 8.0g/cm38.0 g/cm³, which explains why it expands when heated and contracts when cooling.

Water displacement is a clever way to measure volume of irregular objects. When something displaces 300 cm³ of water, that's exactly the volume of the object - no complicated measuring required!

Real Life: This is exactly how archaeologists test whether ancient artifacts are made from the materials they claim to be!

density revision questions and answers – page 4

Sign up to see the content.
It's free!

By signing up you accept Terms of Service and Privacy Policy

Floating and Sinking

Objects float when their density is less than the liquid they're in - that's why ice (about 0.9 g/cm³) floats on water 1.0g/cm31.0 g/cm³. This principle helps you solve tricky problems about boats, fish tanks, and floating objects.

When calculating maximum loads, remember to add up all the masses involved. A 1 kg fish tank plus 15.54 kg of water equals 16.54 kg total - too heavy for a shelf that only holds 16 kg!

For objects that start floating but gradually fill with water, calculate how much extra mass they can take before their overall density reaches 1.0 g/cm³. Once they hit that magic number, down they go!

Physics Fact: This is why damaged ships eventually sink - as water fills the hull, the ship's average density increases until it exceeds that of seawater.

We thought you’d never ask...

Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.

You can download the app from Google Play Store and Apple App Store.

That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.

Similar content

Chemistry

Distillation Techniques Explained

Explore the essential processes of simple and fractional distillation, including step-by-step methods for purifying liquids from mixtures. This summary covers key concepts such as the distillation process, types of mixtures, and practical applications. Ideal for students studying separation methods in chemistry.

1066431
Chemistry

Atomic Structure & Bonding

Explore the fundamentals of atomic structure, ionic bonding, and the periodic table in this comprehensive study resource. Covering key concepts such as subatomic particles, pure substances, and separation methods, this material is essential for understanding chemistry at the foundational level. Ideal for AQA Chemistry Paper 1 preparation.

111,77120
Chemistry

Advanced Chemistry Techniques

Explore essential laboratory techniques in Advanced Higher Chemistry, including titration, chromatography, and gravimetric analysis. This resource covers key concepts such as standard solutions, percent yield, and stoichiometry, providing practical insights for experiments like the preparation of benzoic acid and the determination of aspirin content. Ideal for students seeking to enhance their understanding of chemical analysis and practical skills.

S657918
Chemistry

Separation Techniques Overview

Explore essential physical separation techniques including Filtration and Crystallisation. This summary covers the apparatus, step-by-step procedures, and applications of each method, providing a clear understanding of how to separate mixtures effectively. Ideal for students studying laboratory techniques and separation methods.

72142
Chemistry

Chemistry Separation Methods

Explore key chemistry separation methods including chromatography, distillation, and crystallization. This summary provides clear explanations and labeled diagrams, ideal for GCSE and KS3 students studying mixtures and substances.

848521
Chemistry

Organic Synthesis Techniques

Explore essential methods in organic synthesis and analysis, including thin-layer chromatography (TLC), vacuum filtration, and steam distillation. This summary covers key laboratory techniques for separating and purifying organic compounds, ensuring a comprehensive understanding of the processes involved in organic chemistry. Ideal for A Level Chemistry students.

1376

Most popular content: Biology

Biology

AQA Biology: Key Concepts

Explore essential AQA Biology topics including Photosynthesis, Respiration, Homeostasis, Genetics, and Ecology. This comprehensive knowledge organizer covers key concepts such as energy transfer, hormonal control, and genetic variation, providing a solid foundation for your studies. Ideal for exam preparation and understanding biological processes.

109,494321
Physics

Forces and Motion Overview

Explore key concepts in Forces and Motion, including Hooke's Law, velocity, acceleration, and the principles of moments. This summary covers essential topics such as the relationship between force and extension, terminal velocity, and the impact of safety devices in physics. Ideal for AQA Physics Unit 5 revision.

109,402876
Chemistry

BTEC Applied Science Unit 1 Overview

Comprehensive resource for Year 12 students pursuing a Level 3 Diploma in Applied Science. This booklet covers essential topics including cell structure, chemical properties, and wave theory, providing clear explanations and key concepts to aid in your studies and exam preparation.

125,663130
Biology

Biology paper 1 Summary

Notes for Biology paper 1 contains the full course for AQA higher combined!

114,372109
Biology

Human Heart Circulation

Explore the structure and function of the human heart in this detailed overview. Understand the double circulatory system, the flow of oxygenated and deoxygenated blood, and the significance of heart valves and chambers. Ideal for GCSE AQA Biology students, this summary covers key concepts essential for mastering heart physiology.

119,271976
Biology

Cell Biology Essentials

Explore key concepts in Cell Biology, including cell structure, transport mechanisms, the heart's anatomy, and digestive processes. This summary covers essential topics for AQA GCSE Biology Paper 1, providing a clear overview of eukaryotic and prokaryotic cells, enzyme functions, and plant systems. Ideal for quick revision and exam preparation.

1129,9694,130
Physics

GCSE Physics Practical Experiments

Explore essential GCSE Physics practicals for AQA, covering key concepts such as Hooke's Law, wave properties, thermal insulation, and electrical circuits. This comprehensive guide includes step-by-step procedures, variables, and safety considerations for each experiment, ensuring a thorough understanding of practical applications in physics.

1111,491479
Biology

Biology paper 1 foundation & higher

Pages from the revision guide summarised in a set of words and a brief explanation

111,49518
Combined Science

GCSE Families Overview

Explore key sociological perspectives on families, including functionalism, Marxism, and feminism. This comprehensive guide covers family diversity, changing marriage patterns, and the evolution of gender roles. Ideal for GCSE Sociology students seeking to understand family structures and their societal implications.

115,958159

Most popular content

Sociology

Sociology of Families: Comprehensive Revision

Dive into an extensive overview of family dynamics, perspectives, and patterns in sociology. This resource covers key concepts such as family diversity, gender roles, marriage, and the impact of social policies on family structures. Perfect for A-Level Sociology students preparing for Paper 2.

1274,4062,310
Sociology

Sociology of Education Overview

Explore comprehensive A-Level Sociology notes on the education system, covering key theories, policies, and sociological perspectives. This resource includes insights on marketisation, gender roles, cultural deprivation, and educational inequalities, providing a thorough understanding of how education shapes social stratification and individual achievement. Ideal for exam preparation and in-depth study.

12103,7183,052
Sociology

Comprehensive Crime & Deviance Overview

Explore an extensive revision of crime and deviance topics, including theories, types of crime, and the impact of media. This resource covers key concepts such as Marxism, functionalism, gender and crime, and the influence of globalization on criminal behavior. Ideal for students seeking a thorough understanding of criminology and its various theories. Type: Full Topic Revision.

1252,2311,413
Biology

AQA Biology: Key Concepts

Explore essential AQA Biology topics including Photosynthesis, Respiration, Homeostasis, Genetics, and Ecology. This comprehensive knowledge organizer covers key concepts such as energy transfer, hormonal control, and genetic variation, providing a solid foundation for your studies. Ideal for exam preparation and understanding biological processes.

109,494321
English Literature

An Inspector Calls: Character Insights

Explore in-depth analysis and key quotes for characters in J.B. Priestley's 'An Inspector Calls'. This resource covers Gerald Croft, Inspector Goole, Sheila Birling, Mrs. Birling, Eric Birling, and Eva Smith, focusing on themes of class, gender roles, and social responsibility. Ideal for students aiming for Grade 8 and above.

1126,167924
Criminology

Criminal Justice Overview

Explore key concepts in criminal justice, including the trial process, roles of court personnel, types of offenses, and evidence handling. This comprehensive summary covers essential topics such as jury strengths and weaknesses, the role of the CPS, and the impact of media on trials. Ideal for students preparing for assessments in criminology. Achieved a B grade.

133,78678
Criminology

Criminal Justice Evidence Rules

Explore the essential rules governing the use of evidence in criminal cases, including reliability, admissibility, and relevance. This summary covers key concepts such as the roles of personnel in investigations, the impact of witness testimonies, and the implications of plea bargaining. Ideal for Year 13 criminology students preparing for assessments.

1211,505186
Sociology

Sociological Theories Overview

Comprehensive revision of key sociological theories including Functionalism, Marxism, Feminism, and Interpretivism. Explore concepts like value freedom, identity formation, and the critique of social control. Ideal for AQA A-Level Sociology students preparing for exams. This summary covers essential theories and their implications in sociology, providing a clear understanding of each perspective.

1232,016853
English Literature

An Inspector Calls: Character Insights

Explore the intricate character dynamics and themes in J.B. Priestley's 'An Inspector Calls'. This analysis covers key characters like Mrs. Birling, Sheila, Eric, and the Inspector, alongside themes of social responsibility, class, and gender inequality. Understand the historical context and Priestley's critique of capitalism. Ideal for students seeking a comprehensive understanding of the play's moral messages.

1113,849699

Students love us, and so will you.

4.6/5App Store
4.7/5Google Play
Stefan SiOS user

The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.

Samantha KlichAndroid user

This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.

AnnaiOS user

Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.