Weather & Related Topics to choose from, ranging from Hot to Cold.
 | Evaporation - Find out what factors affect the rate
of evaporation of water. Get 7 small shallow dishes (say saucers) and place the same
amount of water in each one. Set 3 of these where the temperature is the same: the first
where the air is quiet, the second where there is a slight breeze, and the third where the
air is moving rapidly. You may need to use fans on the last 2, set at varying speeds.
Record the length of time it takes for the water to evaporate from each dish.
Place the fourth in a warm place, the fifth at room temperature, the sixth in the
refrigerator, and the seventh in a freezer. Again record the time it takes for the water
to evaporate from each dish.
From which of the first 3 dishes did the water evaporate first? What would you say about
the rate of evaporation and the movement of air?
From which of the last 4 dishes did the water evaporate first? What would you say about
the rate of evaporation and the temperature of air?
|
| Snowflakes - To find out if all snowflakes are the
same.
You will need small sheets of glass (such as microscope slides) or several small pocket
mirrors. Make sure the edges are not sharp. Using bigger sizes may be awkward in trying to
capture a snowflake in the right spot if some are already there. You will also need a
magnifying glass, cardboard, hair spray, bowl, mittens, and a snowy day.
Place the glass and the hair spray outside for a while so they'll be as cold as the
outside air. Put the glass on a piece of cardboard. Spray the glass with a thick layer of
hair spray. Hold the glass out until you've caught a snowflake. Make sure to hold the
cardboard and not the glass, so the heat from your hands won't warm up the glass and melt
the snowflakes. Cover the glass with a bowl to keep away more flakes, then leave the glass
outside to dry (about an hour). You have just preserved the imprints of snowflakes. Study
them under the magnifying glass to see if they are the same.
|
| Relative Humidity - Find out if the relative
humidity is the same or different between indoors and outdoors. Get two thermometers that
measure the same temperature. Wrap the bulb of one in a cotton cloth. Hold the bulb of
this thermometer in water until the cloth is soaked. This is your wet-bulb thermometer.
The other is your dry-bulb thermometer. Lay both side by side. Write down the temperature
that each shows. Now fan with a piece of cardboard. Keep fanning until the temperature of
the wet-bulb thermometer will go no lower. Write down the temperature each thermometer
shows now. The temperature of the dry-bulb thermometer is the actual temperature of the
air. Subtract the wet-bulb temperature from the dry-bulb temperature. Using the chart,
find the relative humidity (in percent). Do this outdoors now. Is there a difference in
the temperature of the air indoors and outdoors? Is there a difference in relative
humidity?
Relative Humidity Chart
| Difference between temperatures of
dry-bulb and wet-bulb thermometers |
Temperature of
dry-bulb thermometer |
| 65o-69o |
70o-74o |
75o-79o |
80o-84o |
85o-90o |
| 2 |
90 |
91 |
91 |
92 |
92 |
| 3 |
85 |
86 |
87 |
88 |
88 |
| 4 |
80 |
82 |
83 |
84 |
85 |
| 5 |
76 |
78 |
79 |
80 |
81 |
| 6 |
71 |
73 |
75 |
76 |
78 |
| 7 |
67 |
69 |
71 |
72 |
74 |
| 8 |
62 |
65 |
67 |
69 |
71 |
| 9 |
58 |
61 |
63 |
65 |
67 |
| 10 |
54 |
57 |
60 |
62 |
64 |
| 11 |
50 |
53 |
56 |
58 |
61 |
| 12 |
46 |
49 |
52 |
55 |
58 |
| 13 |
42 |
46 |
49 |
52 |
55 |
| 14 |
38 |
42 |
46 |
49 |
52 |
| 15 |
34 |
39 |
42 |
46 |
49 |
| 16 |
30 |
35 |
39 |
43 |
46 |
| 17 |
27 |
32 |
36 |
40 |
43 |
| 18 |
23 |
28 |
33 |
37 |
41 |
| 19 |
20 |
25 |
30 |
34 |
38 |
| 20 |
16 |
22 |
27 |
31 |
35 |
| 21 |
13 |
19 |
24 |
28 |
33 |
| 22 |
9 |
16 |
21 |
25 |
30 |
|
 
| Weather Forecasts - Find out how accurate the weatherman is. Each
day for a week, clip the daily weather forecast from the newspaper. Paste the clipping on
a sheet of paper. On the following day, write down what the weather really was. Then rate
the weatherman's prediction for that day.
| Date |
Forecast |
Actual Weather |
Rating of Forecast |
| All Right |
Partly Right |
All Wrong |
| April 4 |
Fair & warmer
Increasing cloudiness |
Fair & warmer
Clouds in afternoon |
X |
|
|
| April 5 |
Increasing cloudiness
Rain, clearing later |
Many clouds
No rain or clearing |
|
X |
|
|
At the end of the week, study your ratings. Was the weatherman wrong more often
than right?
| Color Affect on Heat Absorption - To find out how colors affect
heat absorption. You will need a heat lamp or high-power electric light; two thermometers
that read the same; two shoe boxes; some black, white, red and blue paper or cloth.
Write down the room temperature. Put one thermometer in each box. Wrap one box with white
material, one with black. Place the boxes about two feet from the lamp. After two minutes,
open them and read the thermometers. Record the reading on a chart. Leave the thermometers
in the boxes for five more minutes, then record the temperatures.
Wait until the thermometers again show room temperature. Repeat the entire experiment,
using red and blue coverings for the boxes.
After completing the chart, what conclusions can you draw about how the colors affect heat
absorption?
| Room Temperature |
Temperature in Covered Box |
| After 2 minutes |
After 5 minutes |
| |
Black |
White |
Black |
White |
| |
|
|
|
| |
Red |
Blue |
Red |
Blue |
| |
|
|
|
|
|
