Friday, September 30, 2005
Ess curve on drains
Question:
I you look under your kitchen sink you'll notice that the pipe makes a ess shaped curve. Why is that done?
Hints:
Basically the idea is to trap some water in the bottom part of the ess so that there is a water seal. This way the smells from the sewer doesn't rise up to the house. Also bugs will be less attracted to you sink because it won't be able to smell your cooking, say.
I you look under your kitchen sink you'll notice that the pipe makes a ess shaped curve. Why is that done?
Hints:
- The main reason isn't to recover a dropped item, like a ring, although it helps with that.
- Sewers stink.
- Bugs are attracted to smells.
Basically the idea is to trap some water in the bottom part of the ess so that there is a water seal. This way the smells from the sewer doesn't rise up to the house. Also bugs will be less attracted to you sink because it won't be able to smell your cooking, say.
Ceiling fans can heat the room too?
Question:
It's possible to use a ceiling fan to both cool off a room and heat up a room.
Hints:
A room gets some of it's heat from the people in it and from other electronic devices (lamps, computers, etc.) In Canada we may also have a fireplace and other heaters.
The problem, especially in a tall room, is that the heat rises to the ceiling and does the people in it no good. By turning the ceiling fan on so that it blows upwards it takes that warm air and pushes it down the walls to the floor. By having blow in that direction you don't feel a draft as much.
For a very big room it may be better to have the air blow downwards, it will help keep the warm air down.
It's possible to use a ceiling fan to both cool off a room and heat up a room.
Hints:
- Hot air rises.
- If the fan is blowing air down, it's to cool a room
- If it's blowing up, it's to heat a room.
- If the fan is blowing up too hard it may make the room feel colder.
- Works best if the room is big and tall.
A room gets some of it's heat from the people in it and from other electronic devices (lamps, computers, etc.) In Canada we may also have a fireplace and other heaters.
The problem, especially in a tall room, is that the heat rises to the ceiling and does the people in it no good. By turning the ceiling fan on so that it blows upwards it takes that warm air and pushes it down the walls to the floor. By having blow in that direction you don't feel a draft as much.
For a very big room it may be better to have the air blow downwards, it will help keep the warm air down.
Saturday, September 24, 2005
A/C colder when turned off?
Question: Turn the air-conditioning on in the car for a while and feel the cold air coming out of it. Then turn off the A/C but leave the fan on, it's colder - isn't it. Why would the air get colder after you turn it off?
Hints:
My guess is that when you turn the A/C off the motor stops working (and producing heat) but cooling plates are still cold (for a while). It's inevitable that the A/C unit dumps some heat from the engine and from the compressor etc. into the car. When you turn the A/C compressor off it stops producing this heat and for a while the air is cooler than with the A/C on.
Hints:
- Refrigerators and air-conditioners use energy to take heat from one place and put it in another.
- So there's a part that's cold and a part that's warm, the warm part is usually dumped in the air (outside).
- Air-conditioners have motors that are hot as well.
My guess is that when you turn the A/C off the motor stops working (and producing heat) but cooling plates are still cold (for a while). It's inevitable that the A/C unit dumps some heat from the engine and from the compressor etc. into the car. When you turn the A/C compressor off it stops producing this heat and for a while the air is cooler than with the A/C on.
Monday, September 12, 2005
How can we know if the light in the refrigerator goes off?
Question:
You close the door on the refridgerator and the little light is supposed to go off, but how do we know?
Hints:
If you open the fridge, put your hand on the light bulb. If it's hot, then maybe there's a problem with the switch, but if it's cold and getting warmer it's because the light was off when the door was closed - easy.
You close the door on the refridgerator and the little light is supposed to go off, but how do we know?
Hints:
- Think of being the first one to open the fridge in the morning,
- What happens if the light has been on for a while?
If you open the fridge, put your hand on the light bulb. If it's hot, then maybe there's a problem with the switch, but if it's cold and getting warmer it's because the light was off when the door was closed - easy.
