Loading
Just a moment…
Loading
Just a moment…
Science stories sample
Science Stories opens with a real curiosity, a plain-English explanation, and a check-for-understanding question so new visitors can see the learning pattern first.
Sample wonder card
Your heart beats 100,000 times a day — that’s 35 million times a year. In your lifetime, it will beat 2.5 billion times without ever taking a break.
About how many gallons of blood does the heart pump each day?