How does a breathalyzer work? The alcohol in a person’s breath reacts with a solution, creating an electrical current. The breathalyzer relies on the fact that when you drink alcohol, some of it gets into your lungs and you breathe it out. That’s why, when you take a late bus home on a Friday night, […]
#608 How does a breathalyzer work? Read More »
Why is lead poisonous? It settles in cells and interferes with many different enzymes, preventing the cells from working properly. Lead is a heavy metal that is very dense. It is also fairly soft. These days, a lot is known about lead poisoning, so lead is treated very carefully in factories and in devices that
#604 Why is lead poisonous? Read More »
How long did it take for the sun to get hot? Approximately 10 million years for it to start burning. The sun is hot because of nuclear fusion, which is where hydrogen molecules are squashed together under great pressure to make a helium molecule. There is a difference in the atomic weight of the hydrogen
#602 How long did it take for the sun to get hot? Read More »
When did oxygen appear on Earth? Oxygen appeared on Earth between 2.4 and 2.2 billion years ago. The air we breathe is not made up mostly of oxygen. It is 78.084% nitrogen, 20.934% oxygen, 0.934% argon, 0.035% carbon dioxide, and then a lot of other trace elements. Our bodies need the oxygen and the carbon
#601 When did oxygen appear on Earth? Read More »
How small is nanotechnology? It is between 1 and 100 nanometers. 1 nanometer is 0.000001 mm. It is hard to imagine how small that is. A human hair is about 0.1 mm wide, which makes it 100,000 nm. Nanotechnology is between a thousand and a hundred thousand times smaller than the width of a hair.
#570 How small is nanotechnology? Read More »
How do astronomers work out how far away a star is? They use the star’s parallax and the brightness of the star. The easiest way to work out the distance to a star is to use parallax, but this only works for stars that are less than 3000 light years away. Parallax is a way
#517 How do astronomers work out how far away a star is? Read More »
Can you see past the horizon? Depending on the weather, and the amount of refraction, yes, you can see past the horizon., The horizon is the point where Earth curves away too much for you to be able to see it anymore. Every body in the universe has a horizon, but it depends on the
#510 Can you see past the horizon? Read More »
Why do dry rooms have more static? This is because water in the air naturally conducts electricity. What is static electricity? Every atom has positively charged protons, negatively charged electrons, and neutral neutrons. Almost all atoms have an equal number of protons and electrons, making them stable and electrically neutral. If an atom picks up
#509 Why do dry rooms have more static? Read More »
What is the range of a cell phone tower? The average maximum range of a phone mast is about 40 km, 25 miles. How does a cell phone tower work? Cell towers have detectors and transmitters to receive and transmit radio signals. When you want to look at a website on your phone, my site
#508 What is the range of a cell phone tower? Read More »
How do fluorescent lights work? They pass an electric current through a low-pressure mercury-vapor, which produces light. A fluorescent light is made of a tube of glass that has a tungsten electrode at each end. Inside the tube is a tiny amount of mercury and an inert gas. There is a phosphor powder coated along
#500 How do fluorescent lights work? Read More »
