Crack cocaine
Crack cocaine is a highly addictive form of cocaine that is popular for its intense high.  It is a diluted form of the drug and a small amount of cocaine can be expanded into increasingly larger and weaker amounts of crack cocaine.  It is a cheaper form of powdered cocaine becuse it is usually "cut" with different substances and chemicals such as baking powder and laundry detergent.

# Chemistry
Crack cocaine, often nicknamed "crack", is believed to have been created and made popular during the 1980s. Because of the dangers for 
manufacturers of using ether to produce pure freebase cocaine, producers began to omit the step of removing the freebase precipitate from the ammonia mixture. Typically, filtration processes are also omitted. The end result is that the cut, in addition to the ammonium salt (NH4Cl), remains in the freebase cocaine after the mixture has evaporated. The rock that is thus formed also contains a small amount of water.
Baking soda is now most often used as a base rather than ammonia for reasons of lowered odor and toxicity; however, any weak base can be used to make crack cocaine. When commonly "cooked" the ratio is 3:4 parts cocaine per bicarbonate. This acts as a filler which extends the overall profitability of illicit sales. Crack cocaine may be reprocessed in small quantities with water (users refer to the resultant product as "cookback"). This removes the residual bicarbonate, and any adulterants or cuts that have been used in the previous handling of the cocaine and leaves a relatively pure, anhydrous cocaine base. The net reaction when using sodium bicarbonate (NaHCO3, common baking soda) is:
Crack cocaine usually contains 40% cocaine or less, depending on the degree to which it has been bulked out with other substances.  The other 60%-90% can be made up of almost any available substance the chemists and/or dealers have chosen to use.  For reasons of salability, the person reducing the purity will obviously prefer to do so with a substance that does not excessively alter the color or odor, and a bulked batch will commonly contain some level of acetone and bicarbonate.  The health effects of these are generally mild compared to the health effects of the drug, but a number of highly toxic substances may also be used when available, with serious consequences resulting from consumption.

# Psychological effects
Cocaine is a substance that affects the brain chemistry of the user.  Its main effect is to release a large amount of dopamine, a brain chemical  inducing feelings of euphoria.  The high usually lasts around 15 minutes, after that time dopamine levels in the brain plummet, leaving the user feeling depressed and low.  A typical response among users is to have another hit of the drug, however, the levels of dopamine in the brain take a long time to replenish themselves, and each hit taken in rapid succession leads to increasingly less intense highs.  It is the intense desire to recapture the initial high that is so addictive for many users.
Dopamine is used in the formation of neural networks, or ways that we think.  If someone does something correctly, the brain releases a small amount of the drug to reward and encourage similar behaviors.  Crack use leads to the formation of new neural networks that are formed by large amounts of dopamine, which also contributes to the addictive nature of the drug.  When users think about crack, the new neural pathways that crack has formed invoke positive emotions, as crack becomes more and more associated with intense euphoria. The increasing exposure to the drug decreases the amount of dopamine that the brain naturally releases, which can permanently affect the neural networks.

# Health issues
When large amounts of dopamine are released by crack consumption, it becomes easier for the brain to generate motivation for other activities.  The activity also releases a large amount of adrenaline into the body, which tends to increase heart rate and blood pressure, leading to long-term cardiovascular problems.
As noted previously, virtually any substance may have been added in order to expand the volume of a batch.  Occasionally, highly toxic substances are used, with an indefinite range of corresponding short- and long-term health risks.
The task of introducing of the drug into the body further presents a series of health risks.  Crack cannot be snorted like regular cocaine, so smoking is the most common consumption method.  Crack has a melting point of around 90 C (194 F), and the smoke does not remain potent for long. Therefore, crack pipes are generally very short, to minimise the time between evaporating and losing strength. This often causes cracked and blistered lips, colloquially "crack lip", from having a very hot pipe pressed against the lips.
Another significant health risk is the condition commonly known as "crack lung".

# Signs of Use
- Heavy night sweat
- Lack of flow in conversations
- Chemical odor
- Sweat may smell
- Many All-Nighters
- Crack Lip
- Chewing on Lips
- Can't sit still
- Seems drunk, but no alcohol smell

# Legal status
Crack cocaine is illegal in most parts of the world.  In the United States it is a Schedule II drug under the Controlled Substances Act. In the United Kingdom it is a Class A drug. In the Netherlands it is a List 1 drug of the Opium Law. In Iran, the term crack refers to crack heroin rather than crack cocaine and is a major problem in healthcare.
Law enforcement running drug stings to catch purchasers of crack cocaine often use macadamia nuts to simulate crack cocaine in drug stings. When chopped, these nuts resemble crack cocaine in color.
There has been some controversy over the disproportionate mandatory sentences for crack cocaine under U.S. law since 1987.  Whereas it is a 5-year minimum sentence for possessing 500g of powdered cocaine, the amount of crack needed for a five year sentence is only five grams, a 100:1 ratio.   The U.S. Sentencing Commission has recommended that this disparity be rectified and existing sentences reduced. 

# Crack baby
Crack baby is a pejorative term for a child born to a mother who used crack cocaine during her pregnancy. There remains some dispute as to whether cocaine use during pregnancy poses a genuine threat to the fetus. The official opinion of the National Institute on Drug Abuse of the United States warns about health risks while cautioning against stereotyping:

## Claims regarding threats to fetal and infant health
They also warn about the threat of breastfeeding: "It is likely that cocaine will reach the baby through breast milk."
The March of Dimes advises the following regarding cocaine use during pregnancy: