Words to know
prefix
A word part added to the start of a base that changes its meaning.
base
The main part of a word that carries its core meaning.
pseudonym
A false name used by an author or other person, also called a pen name.
homogeneous
The same all the way through, like salt water or apple juice.
heterogeneous
Made of different parts you can tell apart, like trail mix.
prototype
The first model of an invention, built to test the idea.
Remember from earlier grades
You've collected lots of prefixes: un-, re-, dis-, pre-, mis-, non-, inter-, trans- and more in earlier grades; number and measurement prefixes like mono-, poly-, kilo-, milli- and position prefixes like post-, circum-, extra- in Grade 5; and bene-, mal-, omni-, hyper-, hypo-, ultra-, contra-, syn- plus more chameleon prefixes (ex-, sub-, ob-, ad-, dis-) in Grade 6. You also used the peel strategy: peel the prefixes, peel the suffixes, find the base, put it back together. Grade 7 adds prefixes you'll meet a lot in science, math and history texts.
Let's start with a puzzle
The famous author Mark Twain was really named Samuel Clemens. Mark Twain was his pseudonym.
Peel it: pseud(o) + onym. You learned in Grade 6 that onym/nym means name. So if pseudo- means false, a pseudonym is... a false name. You just figured out a new word in two seconds, without a dictionary. That's what prefixes are for.
Prefixes in your other subjects
- Science: In Grade 7 you learn about pure substances and mixtures. A mixture that looks the same throughout, like salt dissolved in water, is homogeneous. A mixture whose parts you can see, like trail mix or soil, is heterogeneous. Scientists also study microorganisms you need a microscope to see, and macroscopic things you can see with your eyes.
- Math: An equilateral triangle has three equal sides. A point that is equidistant from two places is the same distance from both.
- History: Archaeologists study the Neolithic period (the New Stone Age). Historians look at events in retrospect, looking back with what we know now.
- Technology: Engineers build a prototype to test a design before making the final version.
The equinox happens twice a year, in March and September, when day and night are about the same length everywhere on Earth.
Hands-on activityPrefix-and-base card game
You need: 20 index cards or scrap paper squares, a pencil, and a timer.
- On 10 cards, write prefixes: proto, neo, retro, pseudo, homo, hetero, micro, macro, mega, equi.
- On 10 cards, write bases and word endings: type, natal, spect, nym, phone, geneous, scopic, organism, phone, lateral. (Yes, phone twice.)
- Shuffle each pile separately and lay them face up in two rows.
- Set a timer for 3 minutes. Match prefix + base to build real words (for example mega + phone, homo + phone, equi + lateral). Write each word and its meaning.
- For each word, say a sentence using it.
- Bonus: find a word on a cereal box, in a science book or online that uses one of the Grade 7 prefixes.
What to look for: real words only, with a meaning that matches the prefix. One full set is prototype, neonatal, retrospect, pseudonym, homophone, heterogeneous, macroscopic, microorganism, megaphone, equilateral, but other real words count too, such as microscopic, homogeneous, microphone and heteronym (a word spelled like another but said differently, like lead the metal and lead the verb).