What You Didn’t Know About Halva and Other Cool Facts

• Did you know that halva is made by hand?
Halva is a traditional sweet made by mixing raw tahini (a paste from sesame seeds) with sugar. This mix is usually kneaded by hand, because using a machine can tear the fibers and make the halva less tasty and smooth.

• Did you know what X-rays are?
X-rays were discovered by Wilhelm Röntgen. These special rays can go through many materials, making it possible to see bones and other things inside the body. Since Röntgen didn’t fully understand the rays at first, he called them “X-rays” to mean “unknown rays.” Even though the rays were later named after him, we still call them X-rays today.

• Why do fish live in schools?
Many fish swim in groups called schools. These schools can be small or made up of millions of fish. The main reason fish do this is to confuse predators. When so many fish are moving together, it’s hard for a predator to focus on just one.

• Did you know a starfish can heal itself?
Starfish are special sea creatures with no bones or brain. Most have five arms, though some have even more. If a starfish loses an arm, it can grow a new one. As long as its center stays healthy, it can regrow other parts that get hurt.

• Where is the world’s largest island?
Greenland is the biggest island on Earth. It’s in the North Atlantic Ocean near Canada. Even though it belongs to Denmark, Greenland runs most of its own affairs. About 84% of the island is covered in ice!

• How is a light ray split?
Sunlight is made up of seven different colors, each with its own wavelength. When sunlight shines through a prism, it spreads out into those seven colors, creating a rainbow effect. This is also how real rainbows happen, sunlight passes through raindrops in the air, and the drops act like tiny prisms.

• What is a periscope?
A periscope is a tool used in submarines to see above the water. It has mirrors inside that reflect the view from above, so someone in the submarine can look around without coming up to the surface.