5 to 6 months. Practices intonation by making her voice rise and fall, often in response to baby talk and your facial expressions. Red flag: If your child isn't making vocal sounds by the time she's 6 months old, talk with her doctor. 7 to 12 months. Babbles with greater diversity, making new sound combinations and intonations. Red flag: If your child isn't making vocal sounds by age 7 months, talk with his doctor.
Relative humidity is a measure of the amount of moisture in the air relative to the total amount of moisture the air can hold. For instance, if the relative humidity was 50%, then the air is only half saturated with moisture. Warmer air can hold more moisture than colder air. Why is relative humidity important?
The volume of most physical objects is a function of two other factors: temperature and pressure. In general, the volume of an object increases with an increase in temperature and decreases with an increase in pressure. Some exceptions exist to this general rule.