| Purpose - |
This
easy to make model acts as a simple working thermometer. |
|
| Nature - |
Demonstration |
| Materials - |
Flask,
stopper to fit with hole, flask, glass tube to fit hole, coloured
water |
| Method - |
- About two thirds
fill the flask with coloured water (Red works well).
- Arrange the glass
rod through the stopper so that when the stopper is in the flask, it
will be well below the level of the water, and about 15 cm is
sticking up above the flask.
- Jam the stopper
into the flask
- Blow a little air
into the bottle which will cause an amount of the coloured water to
rise up into the tube above the stopper.
- Mark the level
with a felt tip marker. Now place your ands on the outside of
the flask. You should see the water level in the tube rise.
If you take your hands away the level will slowly drop again.
|
| Safety - |
Nil |
| Explanation - |
As the liquid (and the gas) in the flask
warms up from your hands it expands. This causes the column of
liquid to rise up the tube to account fro the grater volume occupied.
|
| Notes - |
- If you are careful
and have no leaks in your seal, you can calibrate this thermometer
to what ever scale you like.
- Be careful when
you blow into the tube. If you blow too much air into the
flask you will get a jet of water squirt back out at you.
|
|
