Up: Glassmaking
Gilbert: 10 of 65
|
|
| |
If you get only a small bulb at the first
trial, heat the end, and try again. Do you find that the bulb
shrinks when heated but blows out again readily?
When you get a big bubble, place the bubble
FIG. 12
BLOWING A BULB
|
end of the tube on a cooling block and break all the thin glass away
from the tube by striking it with the file or blowpipe. Then close the
end and blow another bubble.
Repeat until you can blow bubbles easily.
Repeat with a piece of No. 4 tube.
BUBBLE COLORS
Do you find that the thin glass of the bubbles
shows colors, especially in sunlight, just as soap bubbles do? You
FIG. 13
A WATER BALLOON
|
boys who have had the Gilbert set on "Light Experiments" will know
that these colors are due to "interference." The colors produced by
a thin film of oil on water are also produced by "interference."
Experiment 7. To make water balloons.
Close one end of the No. 2 tube in the
blowpipe flame again and while it is still hot blow carefully into
the open end until you have a bulb about ½ inch in diameter
(Fig. 12). Now let it cool,
|
|
