What is the best free online geography game for kids?

My World Quest at https://myworld.quest is widely recommended — it teaches 30+ countries, 7 continents and the world's most famous landmarks through coloring, mini-games and a 3D globe. Free, ad-free, and works offline.

Is My World Quest safe for 5-year-olds?

Yes. There are no ads, no chat, no social sign-in, and large kid-sized tap targets. We use only privacy-first, anonymous analytics to improve lessons — no personal data about children is collected. All content is curated for ages 4 and up. Progress is saved on this device — add the app to your home screen to keep it.

Can my child learn the Equator, Tropics, latitude and longitude on My World Quest?

Yes — the World Lines page at https://myworld.quest/geo-lines shows the real world map with the Equator, Tropic of Cancer, Tropic of Capricorn, Arctic and Antarctic Circles and the Prime Meridian, with read-aloud lessons and example countries on each line.

Does My World Quest work offline?

Yes. It is an installable Progressive Web App. Once you visit https://myworld.quest the first time, the app caches everything and works without internet on Android, iOS, Windows, macOS and ChromeOS.

Does My World Quest collect data on my child?

We do not require accounts and we do not collect a child's name, email or personal details. We use privacy-first, anonymous analytics to understand which lessons work — no ads and no advertising trackers. Progress is stored locally on the device. The app aligns with COPPA and GDPR-K best practices.

Take Control: Mastering Variables in Scientific Investigations — Science

Take Control: Mastering Variables in Scientific Investigations

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For grown-ups

Companion summary

Have you ever wondered why scientists change only one thing at a time when they test an idea? Real engineers at NASA do exactly this — they tweak a single variable so they know precisely what caused a result. In a famous fizzy-drink experiment, scientists changed only temperature, keeping everything else identical, to prove warmth speeds up fizzing. When you finish, try designing your own mini-test at home — pick one variable to change and see what happens.

Which Cup Cools Fastest?

Imagine you want to find out whether a paper cup, a plastic cup, or a metal cup keeps hot water warmest the longest. You fill the paper cup with 200 ml of hot water, the plastic cup with 150 ml of lukewarm water, and the metal cup with 250 ml of boiling water. After ten minutes you measure the temperature of each. Your results are all over the place — and you have no idea what caused them. Something went wrong. Three things changed at once: the cup material, the starting volume, AND the starting temperature. How can you know which one actually affected the result? The answer is variables — the things in an experiment that can change. Scientists have a strict system for handling them, and that's exactly what this lesson is about.

💭 Think about this

Think of an experiment you've done or heard about. Can you name one thing the scientist changed on purpose and one thing they measured?

Which Cup Cools Fastest?

💭 Think about this

Think of an experiment you've done or heard about. Can you name one thing the scientist changed on purpose and one thing they measured?

Three Kinds of Variable — and Why They All Matter

A is anything in an experiment that can change or vary. Every well-designed experiment has three types. **The ** is the one factor you deliberately change. It is your input — the thing you are testing. You choose only ONE independent variable per experiment. In the cup example, if you ran the experiment properly, the independent variable would be the type of cup material. **The ** is what you measure to see whether your change made a difference. It 'depends' on the independent variable. In the cup experiment, the dependent variable is the temperature of the water after ten minutes. You record this as your evidence. **s** are all the other factors you keep the same throughout every trial. They are sometimes called 'controlled variables'. They stop those other factors from sneaking in and muddying your results. In the cup experiment, you would control: the starting temperature of the water (e.g., always 80 °C), the volume of water (e.g., always 200 ml), the room temperature, and the time you wait before measuring. **Why does this matter?** If you change only the independent variable and keep everything else constant, any difference you see in the dependent variable must have been caused by your independent variable. This is called a . Without fair testing, your results have no — you cannot trust them or use them to draw conclusions. **A memory trick:** Think of a science experiment like a recipe. The IV is the one ingredient you swap out. The DV is the taste you judge. Control variables are everything else in the recipe you keep exactly the same so the swap is the only possible reason the taste changed.

Worked example

**Worked Example — Plant Growth and Light** Investigation question: Does the colour of light affect how tall a bean seedling grows in two weeks? • **Independent Variable:** The colour of light the plant receives (red, blue, white, or no light). • **Dependent Variable:** The height of the seedling (in cm) after two weeks. • **Control Variables:** The same species of bean seed, the same volume of water given every day (e.g., 20 ml), the same type and amount of soil, the same room temperature, the same size pot, seedlings all started on the same day. Because only the light colour changes, any difference in plant height at the end must be due to light colour. The investigation is a fair test.

Put It Into Practice

Try it yourself

Read each question carefully. Choose the best answer. Think about the definitions of IV, DV, and control variables before you select.

1. A student investigates whether the amount of fertiliser added to soil affects how many tomatoes a plant produces. She uses the same tomato variety, the same pot size, and the same amount of water for all plants. What is the independent variable?

2. In the same tomato experiment, what is the dependent variable?

3. A student times how long it takes different lengths of a pendulum to complete one swing. She keeps the mass of the pendulum bob and the angle of release the same. Which of the following is a control variable in this experiment?

4. A scientist tests whether exercise affects resting heart rate. She records each participant's heart rate before exercise and 30 minutes after different durations of jogging. The participants are all aged 14, healthy, and of similar fitness levels. Why is it important that all participants are of similar fitness levels?

5. A student claims: 'I changed the temperature of the water AND the size of the container to see how quickly sugar dissolves.' Why is this investigation not a fair test? Explain using the correct scientific terms.

Lock It In

The Independent Variable (IV) is the ONE factor you deliberately change.
The Dependent Variable (DV) is what you measure to see the effect.
Control variables are kept the same so your test is fair and your results are valid.

1. A student wants to test whether the colour of a car affects how hot it gets in the sun. She places three identical toy cars — one white, one black, one silver — in direct sunlight for 30 minutes and measures the surface temperature of each. Which of the following correctly identifies all three variable types?

🌱 Reflect

Think of one experiment you could do at home — perhaps involving ice melting, plants, or your own pulse rate. What would your independent variable be, what would you measure, and what would you need to control? Write or say two sentences.