Grouping Things In Science (1969)

no no no no no no no ah a group a group of paper plates in a grocery store what do the plates have in common with other products nearby what do paper plates have in common with detergents napkins and the other items non-foods they're all non-foods non-foods are kept together in one large group all the things that are foods form another large group meats are a subgroup of foods dairy products are another subgroup of foods fruits and vegetables are still other subgroups when we place things into groups and subgroups in this way we're classifying them systems of classification are useful in grouping the items in stores in science systems of classification are also useful living things for instance are grouped by biologists into two large groups plants and animals this group is sometimes divided into two major subgroups one of these subgroups includes animals without backbones such as an octopus a jellyfish a sea urchin a crab and an earthworm these animals without backbones form one subgroup animals such as these animals with backbones form another subgroup but uh so what what good does it do to group a fish with an amphibian with a reptile with a bird with a mammal what can men learn in this way well for one thing scientists have found that these animals share characteristics other than backbones each has a well-developed brain all mammals and other animals with backbones have brains by placing these animals in a group it's possible to compare their brains measuring the part of a fish brain which makes thought possible scientists have found that it's small compared to the rest of its brain in an amphibian this part of the brain is comparatively larger in a reptile still larger in a bird larger yet and its largest in a mammal this relationship gives scientists a means of comparing the intelligence of these animals another way of using groups can be demonstrated with the various kinds of milk in a supermarket the milk is separated into distinct subgroups chocolate milk is in one subgroup whole milk is in another buttermilk in another and skim milk in a fourth the woman finds the kind she wants easily but let's put back the milk for a moment and suppose that several kinds of milk have been mixed together in each row now the milk is no longer arranged by groups but the groups are still identified by the labels imagine how it would be if we removed them now it's almost impossible for the customer to be sure of getting the right kind of milk it's much easier when the milk is arranged and identified according to groups similarly a scientist is often helped by knowing what group something is in in a hospital a technician finds what type of blood a certain patient has he gives this information to a nurse who goes to a blood bank where blood is kept under Refrigeration all human blood is arranged into four groups type O type A B type A and type B grouping blood like this helps the nurse to find the right type quickly it helps her avoid mistakes which could well mean the difference between life and death for her patient to show another use of grouping suppose a customer comes across something new some tiny biscuits crunchies what are crunchies dog biscuits cat food a breakfast cereal something for a snack seeing that Crunchies are grouped near pretzels we can be pretty sure that they are something for a snack can a scientist learn about something new by finding what group it fits in suppose a chemist receives materials for forming a plastic polyethylacrylate polymethylacrylate one of a group of plastics that tells him something about it but exactly what sort of plastic is it is it a soft flexible plastic a hard brittle plastic a foamy flexible plastic the chemist has some idea of what sort of plastic it is because he knows that the word acrylate is related to acrylic acrylic Plastics as a group are hard durable Plastics used in making football helmets tail lights shoe heels and other Plastic Products that have to take rough treatment knowing the characteristics of acrylics as a group the camera suspects that polyethyl acrylate is also a hard durable plastic sometimes a new grouping is useful in a store bacon is generally grouped with other meats but this Grocer's customers look for bacon sometimes when buying eggs are often eaten with bacon so the grocer decided to group the bacon and eggs together in science it's also useful sometimes to change a grouping think of the things astronomers see in the sky first there are tiny points of light for centuries men have known that these are stars and planets but there's another group of objects hazy patches of Light which have not been so easy to identify at first because of the hazy or nebulous appearance of such objects the name nebula was given to each patch of light then in 1924 it was determined that these objects are not all the same some are distant Assemblies of stars but others are concentrations of gas and dust and are much nearer because of the differences between these two kinds of objects it no longer seemed accurate to include both in a single group today the term nebula is usually used for the gaseous clouds the term Galaxy is used to describe each distant assembly of stars a new grouping was made based on new information can you think of other groupings used in science how are rocks grouped [Music] how many ways are there of grouping seeds why are microscopic animals grouped as they are are you beginning to see the value of grouping as a basic tool of science [Music]