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What is plastic? Organic chemistry

By |2018-04-08T11:21:49-07:00June 2nd, 2017|History|

Plastic water bottles There are thousands of different kinds of plastic, from shopping bags to Fisher-Price toys to photographic film, CD's, and plumbing pipes. Some plastics, like chewing gum or rubber, grow as part of plants, but people make most of the different kinds of plastic. We call them "plastics" because they are [...]

What is a protein? Organic chemistry

By |2017-06-02T23:46:07-07:00June 2nd, 2017|Biology, Chemistry|

Proteins are a type of molecule made mainly out of hydrogen and carbon atoms. They are combinations of smaller molecules called amino acids. The first amino acids probably developed into proteins more than four billion years ago on Earth, possibly with the help of ribonucleic acid, or RNA. We don't know whether this process has happened on [...]

What are amino acids? Organic chemistry

By |2019-01-24T12:13:44-07:00June 2nd, 2017|Biology, Chemistry|

A model of the amino acid molecule glycine (red is oxygen, black is carbon, yellow is hydrogen, and blue is nitrogen atoms) What are amino acids? Amino acids are molecules made out of hydrogen, oxygen, carbon, and nitrogen atoms (and a little sulphur). More about hydrogen What are molecules? All our chemistry articles When [...]

What is a virus? Evolution and biology

By |2017-05-30T10:58:32-07:00May 30th, 2017|Biology|

The virus that causes AIDS (greatly magnified) HIV image copyright Russell Knightley Nobody is quite sure whether viruses are living things or not. The first living things may have come from viruses. But it's also possible that viruses evolved from living cells and got gradually less complex and more dependent on their hosts to live. [...]

What is a vascular system? Plant biology

By |2018-04-13T23:51:51-07:00May 30th, 2017|Biology|

Veins in a leaf About 600 million years ago, the first plant cells evolved to be different from animal cells, and from earlier prokaryote cells, because they had a stiff cell wall made of molecules of carbon and oxygen, with some other elements like hydrogen, nitrogen, and calcium as well. In plants, the [...]

What are conifers? Pine trees, gymnosperms

By |2018-04-21T11:56:36-07:00May 30th, 2017|Biology|

Spruce tree - a type of gymnosperm and conifer Near the end of the Carboniferous period, about 300 million years ago, the land on Earth got a lot drier than it had been before. It was drier because plate tectonics was bringing all of the land together into one big continent, Pangaea. Plants that [...]

Collecting pine cones – Gymnosperms project

By |2018-04-16T10:35:31-07:00May 30th, 2017|Biology|

Squirrel eats pine seeds from a cone Go take a walk outside in the fall and collect pine cones on the ground. How many different kinds of pine cones can you find? Can you figure out which tree makes which kind of pine cone? Sit quietly near a pine tree and watch squirrels [...]

Looking at flowers – Angiosperms project – Biology

By |2018-04-16T10:36:08-07:00May 30th, 2017|Biology|

Daffodil with petals and pistil in the middle. Take a long walk around your neighborhood and the park in the late spring and look at all the flowers you see. Can you find ten different kinds of flowers? What does each of these flowers do to attract bees? Is it their color? Their [...]

Flowering plants – Evolution and Biology

By |2017-05-30T09:44:04-07:00May 30th, 2017|Biology|

Lavender flowers smell wonderful! For millions of years, the Earth was covered with ferns and pine trees and moss and mushrooms, without any flowers, grass, or fruit. But about 120 million years ago, in the Cretaceous period, some of these pine trees developed a new way to scatter their seeds that turned out to [...]