VIEW THIS PAGE Fog and mist are essentially the same thing — cloud banks made of suspended water droplets — so why do we have different words for them? The only difference is the density, but the distinction is highly subjective. In aeronautical terms, if a pilot cannot see further than 1km, it is defined as fog. For motorists, visibility must fall below 200m to be classed as fog, otherwise it is known as mist.
Whatever you choose to call it, fog forms when air rapidly cools, causing the water vapor to condense. Fog often forms in coastal areas when warm air moves in from the sea. The temperature of the land is colder than the sea, which causes the air to cool.
In today’s experiment you will recreate this scenario to make your very own fog.
What you will need: some hot water, two bottles and two packs of ice cubes.
Step 1: Fill one bottle with hot water. Tap water will suffice — it does not need to be boiling. Let the bottle stand for ten minutes to heat it up.
Step 2: Fill the other bottle with cold water and allow it to stand.
Step 3: Empty 80 percent of the water out of both of the bottles, so that just a little bit remains at the bottom.
Step 4: Turn both bottles on their side, then take the packs of ice cubes and press them on the bottles. You should notice fog appearing inside the bottle that contained hot water. Hold the ice cubes in place until the bottle is full of fog. No fog will appear in the cold water bottle no matter how long you hold the ice.
1. fog n.
2. mist n.
3. droplet n.
小滴 (xiao3 di1)
4. subjective adj.
主觀的 (zhu3 guan1 de5)
5. coastal adj.
沿海的 (yan2 hai3 de5)
6. appear v.i./v.t.
顯露 (xian3 lu4)
WHAT HAPPENED? 實驗結果
This simple experiment recreated the conditions that occur naturally to form fog. The air inside the hot water bottle cools quickly causing condensation. The air in the other bottle is already cold, so condensation doesn’t form.
(JOHN PHILLIPS, STAFF WRITER)
（翻譯：袁星塵） VIEW THIS PAGE