Relative Humidity Vs

Relative Humidity Vs. Humidity

Humidity is the amount of water vapor in the air. Relative Humidity is the amount of water vapor in the air verses the amount of water vapor the air can hold. Relative Humidity depends upon temperature of the air. The air acts like sponge and absorbs water through the process of evaporation. How much water the air can hold depends upon the temperature of the air. Warm air is less dense and therefore the molecules are further spread apart allowing more moisture between them. Cooler air cause the air molecules to draw closer together limiting the amount of water the air can hold. How does play a role in relative humidity?, if warm moist air suddenly begins to cool then the percent of humidity rises because the distance between the air molecules lessen raising the water vapor percent amount in closing space as the air cools.

A Sling Psychrometer is a weather instrument used to measure the relationship between the wet-bulb and dry-bulb temperature.

Sling Psychrometer

The table below shows the relationship between the dry temperature and the wet temperature, using the table you can calculate the relative humidity of a given space.

Dry-Bulb

Temperature (C)

Difference Between Wet-Bulb and Dry-Bulb Temperature (C)

-20	28
-18	40
-16	48	0
-14	55	11
-12	61	23
-10	66	33	0
-8	71	41	13
-6	73	48	20	0
-4	77	54	32	11
-2	79	58	37	20	1
0	81	63	45	28	11
2	83	67	51	36	20	6
4	85	70	56	42	27	14
6	86	72	59	46	35	22	10	0
8	87	74	62	51	39	28	17	6
10	88	76	65	54	43	33	24	13	4
12	88	78	67	57	48	38	28	19	10	2
14	89	79	69	60	50	41	33	25	16	8	1
16	90	80	71	62	54	45	37	29	21	14	7	1
18	91	81	72	64	56	48	40	33	26	19	12	6	0
20	91	82	74	66	58	51	44	36	30	23	17	11	5	0
22	92	83	75	68	60	53	46	40	33	27	21	15	10	4	0
24	92	84	76	69	62	55	49	42	36	30	25	20	14	9	4
26	93	85	77	70	64	57	51	45	39	34	28	23	18	13	9
28	93	86	78	71	65	59	53	47	42	36	31	26	21	17	12
30	93	86	79	72	66	61	55	49	44	39	34	29	25	20	16

-20	28
-18	40
-16	48	0
-14	55	11
-12	61	23
-10	66	33	0
-8	71	41	13
-6	73	48	20	0
-4	77	54	32	11
-2	79	58	37	20	1
0	81	63	45	28	11
2	83	67	51	36	20	6
4	85	70	56	42	27	14
6	86	72	59	46	35	22	10	0
8	87	74	62	51	39	28	17	6
10	88	76	65	54	43	33	24	13	4
12	88	78	67	57	48	38	28	19	10	2
14	89	79	69	60	50	41	33	25	16	8	1
16	90	80	71	62	54	45	37	29	21	14	7	1
18	91	81	72	64	56	48	40	33	26	19	12	6	0
20	91	82	74	66	58	51	44	36	30	23	17	11	5	0
22	92	83	75	68	60	53	46	40	33	27	21	15	10	4	0
24	92	84	76	69	62	55	49	42	36	30	25	20	14	9	4
26	93	85	77	70	64	57	51	45	39	34	28	23	18	13	9
28	93	86	78	71	65	59	53	47	42	36	31	26	21	17	12
30	93	86	79	72	66	61	55	49	44	39	34	29	25	20	16

-20	28
-18	40
-16	48	0
-14	55	11
-12	61	23
-10	66	33	0
-8	71	41	13
-6	73	48	20	0
-4	77	54	32	11
-2	79	58	37	20	1
0	81	63	45	28	11
2	83	67	51	36	20	6
4	85	70	56	42	27	14
6	86	72	59	46	35	22	10	0
8	87	74	62	51	39	28	17	6
10	88	76	65	54	43	33	24	13	4
12	88	78	67	57	48	38	28	19	10	2
14	89	79	69	60	50	41	33	25	16	8	1
16	90	80	71	62	54	45	37	29	21	14	7	1
18	91	81	72	64	56	48	40	33	26	19	12	6	0
20	91	82	74	66	58	51	44	36	30	23	17	11	5	0
22	92	83	75	68	60	53	46	40	33	27	21	15	10	4	0
24	92	84	76	69	62	55	49	42	36	30	25	20	14	9	4
26	93	85	77	70	64	57	51	45	39	34	28	23	18	13	9
28	93	86	78	71	65	59	53	47	42	36	31	26	21	17	12
30	93	86	79	72	66	61	55	49	44	39	34	29	25	20	16

-20	28
-18	40
-16	48	0
-14	55	11
-12	61	23
-10	66	33	0
-8	71	41	13
-6	73	48	20	0
-4	77	54	32	11
-2	79	58	37	20	1
0	81	63	45	28	11
2	83	67	51	36	20	6
4	85	70	56	42	27	14
6	86	72	59	46	35	22	10	0
8	87	74	62	51	39	28	17	6
10	88	76	65	54	43	33	24	13	4
12	88	78	67	57	48	38	28	19	10	2
14	89	79	69	60	50	41	33	25	16	8	1
16	90	80	71	62	54	45	37	29	21	14	7	1
18	91	81	72	64	56	48	40	33	26	19	12	6	0
20	91	82	74	66	58	51	44	36	30	23	17	11	5	0
22	92	83	75	68	60	53	46	40	33	27	21	15	10	4	0
24	92	84	76	69	62	55	49	42	36	30	25	20	14	9	4
26	93	85	77	70	64	57	51	45	39	34	28	23	18	13	9
28	93	86	78	71	65	59	53	47	42	36	31	26	21	17	12
30	93	86	79	72	66	61	55	49	44	39	34	29	25	20	16