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📡 Invisible signals

How does music travel through the air to a radio? Simple, true invisible signals facts for young children, each with a fun fact, a tiny activity and a question to talk about together.

Tap a question to reveal the answer, share the fun fact, try the tiny activity, then talk about it together.

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How does music travel through the air to a radio? Revealexpand_more

A radio station turns sounds into invisible radio waves and beams them out from a tall antenna. These waves ripple through the air in every direction, and your radio catches them and turns them back into the music and voices you hear. It all travels at the speed of light, so it arrives instantly.

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Talk about itIf you had your own radio station, what would you share on it?

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Did you know?Radio waves can travel so far that we use them to talk to spacecraft far out in space.

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Try itMove a radio around the room and hear the signal get clearer or fuzzier. You are finding where the waves come in best.

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📡📶How does Wi-Fi send the internet without wires?📍How does a map app know exactly where you are?🌬️How does a whistle make its sound?

🤖Still curious?How can many radio stations share the air without mixing up?arrow_forward

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How does a map app know exactly where you are? Revealexpand_more

Your phone listens to signals from satellites circling high above the Earth. Each satellite says exactly where it is and what time it sent its signal, and by comparing several of them your phone works out your own spot on the map. It needs at least a few satellites to pinpoint you accurately.

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Talk about itWhere is a place you would love a map to guide you to?

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Did you know?The satellites that help you navigate are more than twenty thousand kilometres above your head.

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Try itOpen a map app and watch the little dot find you. It just did some clever maths using signals from space.

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📡📶How does Wi-Fi send the internet without wires?📻How does music travel through the air to a radio?🌐What is the internet?

🤖Still curious?Why does GPS work better outdoors than deep inside a building?arrow_forward

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How does a microwave heat food so fast? Revealexpand_more

A microwave oven sends invisible waves into the food that make the tiny water bits inside it jiggle very fast. All that jiggling creates heat right inside the food, so it warms from within instead of from the outside. That is why a microwave heats leftovers far quicker than a normal oven.

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Talk about itWhy do you think we still use ovens if microwaves are so fast?

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Did you know?A microwave heats the water in food, which is why a dry plate stays cool while the food gets hot.

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Try itNotice how microwaved food can be hot in the middle but the plate stays cooler. The waves target the water inside.

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📡📻How does music travel through the air to a radio?❄️How does a fridge stay cold?📶How does Wi-Fi send the internet without wires?

🤖Still curious?Why do metal objects cause sparks in a microwave?arrow_forward

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How does a touchscreen know where you tap? Revealexpand_more

A touchscreen has an invisible grid of tiny electric sensors just under the glass. Your finger carries a little electric charge, so when you touch the screen it changes the electricity at that exact spot. The device notices which point changed and knows precisely where you tapped or swiped.

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Talk about itWhat is your favourite thing to do with a touchscreen?

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Did you know?This is why most touchscreens do not work through a thick glove, which blocks your finger's charge.

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Try itTry tapping a screen with a fingertip and then a fingernail. Notice the screen usually answers only to your skin.

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📡📱How does a screen make pictures?👁️How do robots sense the world?📶How does Wi-Fi send the internet without wires?

🤖Still curious?Why do some touchscreens work with a special pen?arrow_forward

📡 Invisible signals

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