[Ans] What material is used to make vests bulletproof?

Step 1 : Introduction to the question "What material is used to make vests bulletproof?"

Kevlar is a well-known component of personal armor such ballistic vests. The bulletproof vests used by United States military forces, police officers, and SWAT use Kevlar as the key component in their construction. Kevlar is a heat-resistant and strong synthetic fiber, developed by Stephanie Kwolek at DuPont in 1965. It is strong enough to stop bullets and knives, and often described as being "five times stronger than steel on an equal weight basis." It has many other uses too, from making boats and bowstrings to reinforcing tires and brake pads.

[Answer] What material is used to make vests bulletproof?

Step 1 : Introduction to the question "What material is used to make vests bulletproof?"

...Kevlar is a well-known component of personal armor such ballistic vests. The bulletproof vests used by United States military forces, police officers, and SWAT use Kevlar as the key component in their construction. Kevlar is a heat-resistant and strong synthetic fiber, developed by Stephanie Kwolek at DuPont in 1965. It is strong enough to stop bullets and knives, and often described as being "five times stronger than steel on an equal weight basis." It has many other uses too, from making boats and bowstrings to reinforcing tires and brake pads.

[Answer] The original Declaration of Independence is preserved in a bulletproof case filled with which gas?

Step 1 : Introduction to the question "The original Declaration of Independence is preserved in a bulletproof case filled with which gas?"

...The original Declaration of Independence still survives and is one of the most treasured papers in American history. It is stored in a titanium case filled with inert argon gas. The thick bulletproof glass sheet over it is tinted very heavily to prevent damage from sunlight or UV rays. Similar preservation techniques are used to protect the Bill of Rights and Constitution. The Declaration of Independence remains on display in the rotunda of the National Archives, where it is seen by roughly 6,000 tourists every day. At night, when the crowds have all gone home, the case is lowered 22 feet into a vault.