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Black hole

A black hole is a place in space where gravity pulls so much that even light can not get out. The gravity is so strong because matter has been squeezed into a tiny space. This can happen when a star is dying. Because no light can get out, people can't see black holes. They are invisible. Space telescopes with special tools can help find black holes. The special tools can see how stars that are very close to black holes act differently than other stars. How Big Are Black Holes? Blacbe big or small. Scientists think the smallest black holes are as small as just one atom.These black holes are very tiny but have the mass of a large mountain. Mass is the amount of matter, or "stuff," in an object. Another kind of black hole is called "stellar." Its mass can be up to 20 times more than the mass of the sun. There may be many, many stellar mass black holes in Earth's galaxy. Earth's galaxy is called the Milky Way. The largest black holes are called "superma...

Super Glue

 Cyanoacrylates are a family of strong fast-acting adhesives with industrial, medical, and household uses. They are derived from ethyl cyanoacrylate and related esters. The cyanoacrylate group in the monomer rapidly polymerizes in the presence of water to form long, strong chains. They have some minor toxicity.



Chemical structure of ethyl cyanoacrylate, the precursor to many commercial adhesives.

Specific cyanoacrylates include methyl 2-cyanoacrylate (MCA), ethyl 2-cyanoacrylate (ECA, commonly sold under trade names such as "Super Glue" and "Krazy Glue", or Toagosei), n-butyl cyanoacrylate (n-BCA), octyl cyanoacrylate, and 2-octyl cyanoacrylate (used in medical, veterinary and first aid applications). Octyl cyanoacrylate was developed to address toxicity concerns and to reduce skin irritation and allergic response. Cyanoacrylate adhesives are sometimes known generically as instant glues, power glues or superglues. The abbreviation "CA" is commonly used for industrial grade cyanoacrylate.

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