A scientific model is a simplified abstract view of a complex reality. Scientific models are used as a basis for scientific work. They can be used to explain, predict, and test, or to develop computer programs or mathematical equations.

An example of a complex model is the software used for weather forecasts. The program is based on equations for the variables which affect weather. Meteorological data is fed in, and the program produces predictions (graphs and data) of future weather patterns.

A scientific model represents complex objects, events, and physical processes in a logical way.

They are an image of an original, which can be a model itself. 
Scientific models only have those details of the object or image modeled that are relevant.
There is no strict mapping between a model, and the original object it models. Models may be valid only for a given  time interval, for a given object,  or for a given purpose.

Examples 
For instance, models of our universe are part of astrophysics - the biggest things in nature - and physics - the smallest. This is not usually what we mean by nature, however. We mean the models studied in biology, ecology, economics, environmental health and healing. Most models of nature are of things that humans really affect directly, and which affect humans back:

Toxic waste 
For instance, to dump toxic waste in a river will harm others down the river. But without models of nature we do not know who, and cannot say how much is harmed or harmful.

Effects 
Models of nature affect human decision-making. They are very important to human health, wellness and economics. They also matter in ethics, since most people wish to reduce harm done by their decisions. They matter in law because harms can be proven to have been done in a court.

Forests 
A forest is very hard to bring back to life, once it is degraded. Smaller models of bits of nature help to understand how much must be left, so future generations can use nature too.

Effects on nature 
In many ways humans and nature can be said to be in conflict. Natural capital like soil and large healthy trees, which nature needs to make more of itself, is also useful to humans as natural resources. To know how much can be drawn out of nature, before it dies, is important. This is another reason for a model:

There are three main ways in which models of nature affect human life:

The environment 
 Environment and wellness are about human health and healing and nutrition. These focus on 'what goes in' the human body or senses, and on how to extend lifespan and increase vitality. Human happiness depends on being part of something alive outside them, according to this view. Gardening for instance can make them happy, just by focusing them on growing and putting themselves outside.

Economics 
 Ecology and economics study resources, waste, energy, food and diet and how choices affect nature in many other places. These ideas say to focus on how to buy local, conserve energy, and to reduce, re-use, recycle goods, to reduce competition between humans. Human bodies are part of nature, according to this view, and must be seen as part of ecology - for instance the urban ecology of cities.

Ecology 
 Deep ecology and animal rights say nature should exist only for itself. Human morality should be about leaving it alone. This ideology says to focus only on working to conserve habitat, increase biodiversity, and buy moral to not help damage things. It says to do all this without any measurable direct benefit to humans, even themselves. Humans are more like caretakers in this view which is often part of religion. It puts ethical limits on the actions of scientists, for instance it argues against animal experiments or genetically modified food. It usually is seen as opposed to science, not part of it. Its models of nature are not usually accepted by most scientists, but they matter in politics.

Preservation 
To preserve nature, ecology movement activists now cooperate in a global power network. It includes not just parties in politics but also NGOs like Greenpeace, Earth First or World Wide Fund for Nature.

Effects on maps 
One model of nature they have agreed on is a map that shows ecoregions, which are the natural borders of ecology maps. According to this map, there are 867 regions divided into 8 ecozones - plus others which are in the ocean.

Effects on language 
Most anthropologists agree that aboriginal languages have a small model of local nature in them. For instance, there will be more words to describe snow in an Arctic language, and more words to describe shades of green in a rainforest. This is part of the reason to use ecology borders in politics, since people who do not live inside the border do not see or make the same distinctions about nature.

Effects on humans 
A very small number of people think that humans do not need nature at all, and can replace everything that it does. To prove them wrong, some economists made another model of nature:

Economists study nature's services to see how hard it would be to replace what nature does for humans. They showed in 1995 that the services nature performed for humans were more valuable than all services humans perform for each other all over the world. The value of Earth as a living thing was much more than we could ever afford to replace with our own technology. There has been no real disagreement about any of this.

Pricing all the value of Earth to humans gives a huge number - which proves the pricing is right, since, we must put a high price on anything we have no way to replace.

References 

 
Interdisciplinary fields
Reality