Helium for Kids
HEE-lee-um · Noble gas
I wonder… Why do party balloons float away?
Helium is the gas that makes party balloons float. It's so calm that it almost never joins with other elements.
Quick facts
- Atomic number
- 2
- Symbol
- He
- Atomic mass
- 4.003
- Type
- Noble gas
- Discovered
- 1868
- Discovered by
- Pierre Janssen and Norman Lockyer
- Name means
- Named after Helios, the Greek god of the Sun
- At room temperature
- Gas
How helium was discovered
Part 1 of 3
A dark day in India
In 1868, a French astronomer named Pierre Janssen traveled all the way to India to watch the Moon cover up the Sun. This is called a total solar eclipse.
Part 2 of 3
A mystery yellow line
Janssen looked at sunlight through a special tool that splits light into a rainbow. He spotted a bright yellow line that didn't match anything known. An English scientist, Norman Lockyer, studied it too. He decided it came from a brand-new element in the Sun!
Part 3 of 3
Found on Earth at last
Lockyer named it helium, after Helios, the Greek god of the Sun. For 27 years, no one could collect any helium here on Earth. Then in 1895, William Ramsay found it trapped inside a rock.
What is helium used for?
Floating balloons
Helium is lighter than air, so balloons filled with it float up, up, up. Giant parade balloons use it too.
Helping doctors
Liquid helium keeps the huge magnets in MRI machines super cold. MRI machines let doctors see inside your body.
Blimps
The big blimps you see floating over stadiums are filled with helium.
Fun facts about helium
Why do voices go squeaky?
Sound travels about 3 times faster through helium. That changes how your voice echoes inside your throat and mouth, so it sounds squeaky. But never breathe helium from a balloon. It can be dangerous!
How cold can it get?
Liquid helium is the coldest liquid in the world: about −269 °C (−452 °F)!
Space first?
Helium was spotted in the Sun almost 30 years before anyone collected it on Earth.
Inside a helium atom
Helium's first electron track is completely full with 2 electrons. That's why it's so calm.
Quiz yourself
1. Where was helium first discovered?
- In a volcano
- At the bottom of the ocean
- In the Sun
Show the answer
In the Sun. Scientists spotted helium's yellow light in sunlight during an eclipse in 1868.
2. Why do helium balloons float?
- Helium is lighter than air
- Helium is magnetic
- Helium is hot
Show the answer
Helium is lighter than air. Helium is lighter than air, so the heavier air pushes the balloon up.
Try it at home (with a grown-up): How strong is one balloon?
Grown-up needed! Only do this with a grown-up right next to you, the whole time.
You'll need
- A grown-up helper
- 1 helium balloon with a string (use a foil balloon if anyone is allergic to latex)
- A box of paper clips
What to do
- Guess first: how many paper clips can one helium balloon lift? Write your guess down.
- Hook one paper clip onto the end of the string.
- Keep adding paper clips, one at a time.
- Stop when the balloon can't float up anymore. Count the clips!
- Was your guess close? Check again tomorrow. Helium slowly leaks out of balloons, so it lifts less each day.
- Grown-up’s job When you're all done, let the helium out somewhere airy, then throw the balloon away.
Safety rules
- Never breathe in helium from a balloon. It can make you pass out.
- Never put a balloon, or a piece of one, over your face or in your mouth.
- Popped balloon pieces are a choking danger. A grown-up picks up every piece right away.
- Keep balloons away from kids under 8 and pets.
- Never let a balloon go outside. Foil balloons can get tangled in power lines.
Draw it
Draw a helium atom: 2 protons and 2 neutrons in the middle, and 2 electrons around the outside.
Riddle
“I make party balloons float, and I was spotted in the Sun before anyone collected me on Earth. What am I?”
Explore helium with animations, read-aloud and a drawing pad
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