### substance:

Hard material
* are important in industry.
* reflect and soft materials absorb.
+ Hardness: Materials science :: Physics
  * Hardness' is a measure of how hard a material is. Some examples of hard materials are diamond, carbides, quartz, alumina, and tempered steel. Harder materials are more difficult to cut and shape than softer ones. They are also usually more brittle. Hard materials are important in industry.

Harmful substance
* Most harmful substances come in contact.
* Some harmful substances accumulate in intestines
  - produce chemicals

### substance:

Hazardous material
* Most hazardous materials affect particular organs of the body.
* Some hazardous materials are more difficult to avoid, such as vapors from gasoline
  - safety hazards and can cause fires or explosions
  - have multiple risks and require more than one hazard label
* are a common and important part of our everyday life
  - chemicals that are harmful to humans and to the environment
  - commonplace in workplaces
  - items closely monitored by state officials
  - materials that pose a risk to people or to the environment
  - present in every community in the country
* can be biological, chemical, or nuclear in nature
  - in the soil, the air, the water or can be part of the building itself
  - solids, liquids or gases and transported in a variety of containers
* require careful handling, storage, and disposal.

Hazardous substance
* Some hazardous substances dissolve very slowly in water
  - used in spray painting are also a fire or explosion risk
* are common in our daily lives
  - essential parts of our daily lives
* play important roles in our everyday quality of life.
* take their toll on the lives and health of individuals innocent to their risks.

Homogeneous substance
* Some homogeneous substances have chemical compositions
* Some homogeneous substances have definite chemical compositions
* is without character and it is inert.

Hot material
* rise from the mantle.
* rises, while cold gases sink.

Humate
* All humates are different, just like soils are different.
* are materials
* are the salt form of humic acids
  - salts of humic acids, collectively, or the salts of humic acid specifically
* have a wide range of applications in addition to their use as soil amendments.
* play a direct role in determining the production potential of a soil.

### substance | humate:

Peat
* Some peats have millions of spores and pollen per gram.
* increase the water storage capacity of sandy soils and the permeability of heavy clay soils.

### substance | humate | peat:

Sphagnum peat
* is also a good source of organic matter
  - deficient in macronutrients as well as micronutrients
  - harvested from bogs in Canada and the northern United States
  - superior to Colorado mountain peat
* little inhibitory due to acidity.

Humectant
* Are substances that promote water retention due to their hygroscopicity.
* are a major element in all toothpastes
  - compounds that attract and hold moisture into the hair
  - substances that attract water and include glycol, glycerin, sorbitol, and gelatin
* attract water into the skin, and are useful on unbroken skin but can cause stinging.
* draw moisture into the skin.
* retain natural internal moisture by drawing it from the air.
* stop the toothpaste from solidifying.

### substance | humectant:

Natural humectant
* help retain precious moisture vital to basic skin care.
* helps retain moisture in hair.
* replace lost moisture leaving the hair with high lustre and manageability.