Family Pedigree

Thursday February 7, 2019

A pedigree analysis chart, usually used for families, allow us to visualize the inheritance of genotypes and phenotypes (traits). In this chart, the P, F1, and F2 generation are represented by the numerals I, II, and III respectively. Notice that those carrying the trait are colored red, and those not carrying the trait (the normal-looking ones) are in blue. The normal, non-trait carrying organisms on the chart are called the wild-type.


The term wild-type is used in genetics often to refer to organisms not carrying the trait being studied. For example, if we were studying a gene that turns house-flies orange, we would call the normal-looking ones the wild-type.


Let’s make a pedigree for your family. Here’s what you need:


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Extracting DNA in your Kitchen

Monday May 2, 2011

If the cell has a nucleus, the DNA is located in the nucleus.  If not, it is found in the cytoplasm.  DNA is the genetic material that has all the information about a cell.


DNA is a long molecule found in the formed by of two strands of genes. DNA carries two copies—two “alleles”—of each gene. Those alleles can either be similar to each other (homozygous), or dissimilar (heterozygous).


We’re going to learn how to extract DNA from any fruit or vegetable you have lying around the fridge. Are you ready?


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Tracking Traits

Monday May 2, 2011

Why do families share similar features like eye and hair color? Why aren’t they exact clones of each other? These questions and many more will be answered as well look into the fascinating world of genetics!


Genetics asks which features are passed on from generation to generation in living things. It also tries to explain how those features are passed on (or not passed on). Which features are stay and leave depend on the genes of the organism and the environment the organism lives in. Genes are the “inheritance factors “described in Mendel’s laws. The genes are passed on from generation to generation and instruct the cell how to make proteins. A genotype refers to the genetic make-up of a trait, while phenotype refers to the physical manifestation of the trait.


We’re going to create a family using genetics!


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Family Pedigree

Monday May 2, 2011

A pedigree analysis chart, usually used for families, allow us to visualize the inheritance of genotypes and phenotypes (traits). In this chart, the P, F1, and F2 generation are represented by the numerals I, II, and III respectively. Notice that those carrying the trait are colored red, and those not carrying the trait (the normal-looking ones) are in blue. The normal, non-trait carrying organisms on the chart are called the wild-type.


The term wild-type is used in genetics often to refer to organisms not carrying the trait being studied. For example, if we were studying a gene that turns house-flies orange, we would call the normal-looking ones the wild-type.


Let’s make a pedigree for your family. Here’s what you need:


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Cell in Action

Monday May 2, 2011

Cells make up every living thing. Take a look at all the living things you can see just in your house. You can start off with you and your family. If you have any pets, be sure to include them. Don’t forget about houseplants as well – they’re alive. Now take a walk outside. You’ll likely see many more plants, as well as animals like birds and insects. Now imagine if all those living things were gone. That’s how it would be if there were no cells, because cells are what all those living things are made of.


Animals, plants and other living things look different, and contain many different kinds of cells, but when you get down to it, all of us are just a bunch of cells – and that makes cells pretty much the most important thing when it comes to life!


Here’s a video on the difference between animal and plant cells:



Are you wondering what all the different organelles are inside the cell? Here’s a video that goes into all the cool detail (note – this video is more for advanced students):



 


Now pull out your science journal! As you watch this video below, write down the organelles you see and describe what you think is happening.



What’s going on?


The endoplasmic reticulum, shown in red, transports proteins to the Golgi Apparatus, shown in blue. The Golgi Apparatus packages proteins and sends them where they are needed, either in the cell, or to the cell membrane for transport out of the cell.


Protozoa in the Grass

Monday May 2, 2011

This experiment allows you to see protozoa, tiny-single celled organisms, in your compound microscope. While I can go in my backyard and find a lot of interesting pond scum and dead insects, I realize that not everybody has a thriving ecosystem on hand, especially if you live in a city.


I am going to show you how to grow a protozoa habitat that you can keep in a window for months (or longer!) using a couple of simple ingredients.


Once you have a protist farm is up and running, you’ll be able to view a sample with your compound microscope. If you don’t know how to prepare a wet mount or a heat fix, you’ll want to review the microscope lessons here.


Protozoa are protists with animal-like behaviors. Protists live in almost any liquid water environment. Some protists are vital to the ecosystem while others are deadly.


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Celery Stalk Water Race

Monday May 2, 2011

If you think of celery as being a bundle of thin straws, then it’s easy to see how this experiment works. In this activity, you will get water to creep up through the plant tissue (the celery stalk) and find out how to make it go faster and slower.


The part of the celery we eat is the stalk of the plant.  Plant stalks are designed to carry water to the leaves, where they are needed for the plant to survive.  The water travels up the celery as it would travel up any plant.


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Bacteria in Humans and Dogs

Monday May 2, 2011

Some organisms, like bacteria, consist of only one cell. Other organisms, like humans, consist of trillions of specialized cells working together. Even if organisms look very different from each other, if you look close enough you’ll see that their cells have much in common.


Most cells are so tiny that you can’t see them without the help of a microscope. The microscopes that students typically use at school are light microscopes.


Robert Hooke created a primitive light microscope in 1665 and observed cells for the very first time. Although the light microscope opened our eyes to the existence of cells, they are not useful for looking at the tiniest components of cells. Many structures in the cell are too small to see with a light microscope.
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Colored Flowers

Monday May 2, 2011

When plants are watered, the water travels up the roots of the plant, and to all of the plant’s parts.  So, with sunlight and time, the colored water eventually made to the plant’s flowers, creating the color change you observed.


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Cell Walls of Cotton

Monday May 2, 2011

cotton-plantThe cell wall organelle supports and protects the cell.  Cell walls have small holes, called pores, in them.  This lets water, nutrients, and other substances into the cell.


Here’s what you do:


First, take out your science journal. Write down how many cotton balls you think will fit into a full glass of water without spilling any water.


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Osmosis in Potatoes & Beans

Monday May 2, 2011

One way substances can get into a cell is called passive transport. One special kind of passive transport is osmosis, when water crosses into the cell. This experiment allows you to see the process of osmosis in action. Are you ready?


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Carbon Dioxide and Photosynthesis

Monday May 2, 2011

Photosynthesis is a process where light energy is changed into chemical energy.  As we said in the last section, this process happens in the chloroplast of plant cells.  Photosynthesis is one of the most important things that happen in cells.


In fact, photosynthesis is considered one of the most important processes for all life on Earth.  It makes sense that photosynthesis is really important to plants, since it gives them energy, but why is it so important to animals?  Let’s learn a little more about photosynthesis and see if we can answer that question.


There are many steps to photosynthesis, but if we wanted to sum it up in one equation, it would be carbon dioxide (CO2) + water (H2O) makes glucose (C6H12O6) and oxygen (O2).  These words can be written like this:


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Onion Mitosis

Monday May 2, 2011

In eukaryotes there is a nucleus, so a more complex process called mitosis is needed with cell division. Mitosis is divided into four parts, or phases:


Phase 1 – Prophase: In this phase the nuclear membrane begins to break down and the DNA forms structures called chromosomes.


Phase 2 – Metaphase: In this phase the chromosomes line up along the center of the parent cell


Phase 3 – Anaphase: In this phase, the chromosomes break apart, with a complete set of DNA going to each side of the cell


Phase 4 – Telophase: In this phase, a new nuclear membrane forms around each of the sets of DNA


The four stages of mitosis (the cell at the top has not started mitosis) lead to two daughter cells.


A little after telophase, the cytoplasm splits and a new cell membrane forms.  Once again, two daughter cells have formed.  Take a look at this animation for a good overview of mitosis and see if you can identify all the phases.


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Cool Carrot Osmosis

Monday May 2, 2011

The carrot itself is a type of root—it is responsible for conducting water from the soil to the plant. The carrot is made of cells. Cells are mostly water, but they are filled with other substances too (organelles, the nucleus, etc).


We’re going to do two experiments on a carrot: first we’re going to figure out how to move water into the cells of a carrot. Second, we’ll look at how to move water within the carrot and trace it. Last, we’ll learn how to get water to move out of the carrot. And all this has to do with cells!


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Genetics Exercises

Monday May 2, 2011

Let’s see how much you’ve picked up with these experiments and the reading – answer as best as you can. (No peeking at the answers until you’re done!) Just relax and see what jumps to mind when you read the question. You can also print these out and jot down your answers in your science notebook.


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Cells Exercises

Monday May 2, 2011

Let’s see how much you’ve picked up with these experiments and the reading – answer as best as you can. (No peeking at the answers until you’re done!) Just relax and see what jumps to mind when you read the question. You can also print these out and jot down your answers in your science notebook.


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Answers to Cells Exercises

Monday May 2, 2011

Let’s see how you did! If you didn’t get a few of these, don’t let it stress you out – it just means you need to play with more experiments in this area. We’re all works in progress, and we have our entire lifetime to puzzle together the mysteries of the universe!


Simply click here for printable questions and answers.


Answers:
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Answers to Genetics Exercises

Monday May 2, 2011

Let’s see how you did! If you didn’t get a few of these, don’t let it stress you out – it just means you need to play with more experiments in this area. We’re all works in progress, and we have our entire lifetime to puzzle together the mysteries of the universe!


Simply click here for printable questions and answers.


Answers:
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Exercises for Living Organisms

Monday May 2, 2011

Let’s see how much you’ve picked up with these experiments and the reading – answer as best as you can. (No peeking at the answers until you’re done!) Just relax and see what jumps to mind when you read the question. You can also print these out and jot down your answers in your science notebook.


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Answers to Living Organisms Exercises

Monday May 2, 2011

Let’s see how you did! If you didn’t get a few of these, don’t let it stress you out – it just means you need to play with more experiments in this area. We’re all works in progress, and we have our entire lifetime to puzzle together the mysteries of the universe!


Simply click here for printable questions and answers.


Answers:
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Is It Alive?

Monday May 2, 2011

How can you tell if something is alive or not? For this activity, grab a pencil and paper and watch the video below. Write down whether you think it is alive or not, and what action is going on to make you think it’s alive. Ready?




Walk Around the House

Monday May 2, 2011

cookiesWalk around your house. In each room, make an observation by using your senses (sight, sound, smell, touch and taste). Based on this observation, ask a question.


For example, if you observe that the kitchen smells like cookies, you might ask, “Has someone been baking cookies?”


Create a testable hypothesis that answers each of your questions. Feel free to test any of your hypotheses.


Conducting Research

Monday May 2, 2011

Think of an organism (bacteria, fish, reptiles…) that interests you. With adult help, search the Internet to find five web pages about this organism.


Answer the questions below about each web site in your science journal:


1. Who wrote the site? (If unknown, write “unknown.”)


2. If the site has an author, does the site list his or her qualifications for writing about the organism?


3. Is there an organization that created the site? If so, who are they?


4. Does the site give you a way to contact the author and/or organization if you have questions?


5. Based on your answers to questions 1-4 above, do you trust this site as being a good source for information about the organism? Why or why not?


Thumb War Hypotheses

Monday May 2, 2011

thumb-warDifferent people have different sized thumbs and wrists. Do you think this will affect people’s success at winning a thumb war?


Open up your science journal and write a hypothesis to answer this question.
Now, find as many volunteers as you can. Measure everyone’s wrist and thumb circumference by wrapping the string around it and measuring the string used with the ruler. Write this down in your journal also.


Have each volunteer have a thumb war with each of the other volunteers three times.


Keep track of his or her victories and record all results in your journal.


You can create a graph of your results, with wrist circumference on the horizontal and number of victories on the vertical axis.


How does your data compare with your hypothesis?


Classifying Objects

Monday May 2, 2011

silverwareGrab a handful of buttons. Make sure there are all different kinds and colors.


If you don’t have buttons, use any pile of objects, like matchbox cars, coins, nuts, etc.


Now group the buttons according to size, color, texture, number of holes, shape, etc.


You can do this activity with shells, peanuts, plant leaves, or the back of your desk drawer. Is it easier to organize the non-living or the living things?


Similar and Different Organisms

Monday May 2, 2011

We're going to access another website (Seaworld) that has a HUGE catalog of living organisms and their scientific names. Here's how you do it:
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Membranes

Monday May 2, 2011

Here’s a fun experiment that shows you how much stuff can pass through a membrane. Scientist call it the  semi-permeability of membranes.


Before we start, take out your science journal and answer this question: What do you think will happen when we stick a piece of celery into a glass of regular water. Anything special?


What if we add a teaspoon of salt to the water? Now do you think anything will happen?
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Microscope Shopping List

Saturday July 31, 2010

This lab is an introduction to the microscope. We’re going to cover how to use a compound microscope, the basics of optics, slide preparation, and why we can see things that are invisible to the naked eye.



What’s a compound microscope? Compound microscopes are basically two lenses put together to make things appear larger. If you’ve ever used magnifying glass, you’ve noticed how the lens makes words easier to read. If you were to look through two magnifiers (one stacked on top of the other with space in between), you’ve seen this effect multiply to create an even larger image. That’s exactly what a compound microscope does. It uses stacked lenses to greatly increase the magnification.


I’ll show you how to get the most out of your investment by learning how to operate a microscope and prepare specimen slides. Click here for a printer-friendly version of this page.


Selecting a Microscope

The first thing you need to do is select a compound microscope. Cheap microscopes are going to frustrate you beyond belief, so we’ve provided recommendations that will get last your kids through college.


It can be a daunting task to find high quality microscopes and accessories at affordable prices. Here are a couple of recommendations for microscope and equipment that will last your kids through college. You’ll also need additional items like slides, coverslips, tweezers, and other basic equipment.

The microscope you select will last a long time. Expect to pay at least $100 for a decent microscope that will provide many years of use. Here are ones we recommend investing in…


Economy Model: The Kids Microscope is a great entry level microscope for under $110. It meets the optical requirements to do our microscope labs but has only single intermediate focusing. It is also available in a cordless LED model that you can use in the field. If your children are young, this may be a good scope to start out with.
Student Model: The Home Microscope is an excellent 5th – 12th grade level microscope with fluorescent lighting that will really meet all the microscope needs of most families. It is well built with very good optics and will stand up to many years of use. I recommend the additional mechanical stage, as stage clips can be frustrating when working at high power!
Advanced Model: There is a Serious Student Model that includes the mechanical stage, iris diaphragm for lighting control, extra 100x oil immersion objective for 1,000x magnification, and immersion oil. This one will take you far in your studies of the micro world. Using the 100x objective with immersion oil is more challenging but also very rewarding as your child is able to see more and develop advanced microscope skills.
All-the-Bells-and-Whistles Model: The Ultimate Home Microscope is really a great microscope (and very similar to the one I personally use with the teaching head attached). This is a university/lab level microscope that is built to withstand the rigors of daily use. This scope is heavier, sturdier, and has all the advanced features like 100x oil immersion objective, iris diaphragm lighting control and a mechanical stage with very easy to use controls. It is also available in a binocular model that is more comfortable to use.When your microscope arrives, keep it in its packaging until you watch the next video. I’ll show you how to handle it, store it, and where not to touch.
No matter which microscope you select, you’ll want to be sure it meets these criteria: at least three objectives (40X, 100X, 400X) and the optics are all glass to provide better quality images and the microscope frame construction is metal to provide the durability you want. Most microscopes include a dust cover and custom fit styrofoam box for safe storage. Optional additions include a mechanical stage (which we highly recommend), a fourth 100x objective lens (for 1,000x magnification), and adjustable iris diaphragm for better lighting/contrast control.
By the way, if you’re considering the the fourth 100x lens, make sure you get the special “oil immersion” objective. Light tends to do weird things when you magnify it that much, and to avoid these kinds of problems, scientists use a drop of oil on the slide to connect the objective with the slide. However, you can’t do this trick with just any objective lens – you need to have a special kind of lens that won’t get mussed up when contacted with oil (hence the “oil immersion” type).

Where to Find Other Essentials

In addition to a microscope, you’ll also need additional items like slides, cover slips, tweezers, and other basic equipment. Here’s what you need to complete the labs in this section:



Supplemental Equipment:

These items are not required for this lab, however if your budget allows for these items in the future, they are very nice to have…

Prepared Slide Sets: Using our labs you will learn to make different kinds of microscope slide mounts and examine a variety of samples that you can easily collect. Prepared slides contain specimens that have been professionally stained and prepared so that you can expand your microscope studies to a great variety of plant and animal life that you would otherwise not have access to. The general slide set and the biology slide set are two sets that contain a great variety of specimens to expand your microscopic studies.
Microscope Case: While the dust cover and styrofoam box that come with your microscope provide a good degree of protection, you may want to consider a microscope case to provide greater protection and convenience in carrying and storing your microscope. These cases have the added advantage of also storing your microscope accessories with your microscope in one location.
Digital Microscope: This one is actually cheaper than most optical models listed above, and I’ve used it when teaching kids. The best part is, all kids can view at the same time, and you can take both pictures and video of your specimens while viewing. It’s really a great deal for the price. The one I really like is the Celestron 44340 LCD.

Can’t afford a microscope?

I’ll show you how to build a very simple microscope using two handheld magnifying lenses! All you need is an afternoon, a few kids, and two magnifiers per kid. Now it doesn’t come close to any of the microscopes above, but it will allow you to do some basic experimentation. (The magnifiers do not need to be the same magnification.) Gather up a few coins, dead bugs, and plant specimens and you’ll be all set for a microscope adventure.


Microwhat?

Saturday July 31, 2010

Welcome to our unit on microscopes! We’re going to learn how to use our microscope to make things appear larger so we can study them more easily. Think about all the things that are too small to study just with your naked eyeballs: how many can you name?


Let’s start from the inside out – before you haul out your own microscope, we’re going to have a look at what it can do. I’ve already prepared a set of slides for you below.  Take out a sheet of paper and jot down your guesses – here’s how you do it:


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Anatomy of the Microscope

Saturday July 31, 2010

Nose? Objective? Stage? What kind of class is this?  Well, some of the names may sound a bit odd, but this video will show you what they are and how they are used. As you watch the video, touch the corresponding part of your microscope to get a feel for how it works.


NOTE: Be very careful NOT to raise the stage too high or you’ll crack the objective lens!  Always leave a space between the stage and the lens!! Anytime you use the coarse adjustment knob, always look at the stage itself, NOT through the eyepiece (for this very reason). When you use the fine adjustment knob, that’s when you look through the eyepiece.




More questions to ask:

1. After you’ve learned the different parts of the microscope, swing around and teach it to a nearby grown-up to test your knowledge. See if you can find all these parts: eyepiece, base (legs), objective lens, eyepiece, diaphragm (or iris), stage, fine and coarse adjustment knobs, mirror/lamp, nose.


2. Show your grown-up which parts never to touch with your fingers.


3. What’s the proper way to use the coarse adjustment knob so you don’t crack the objective lens?


Care and Cleaning

1. Pick up the microscope with two hands. Always grab the arm with one hand and the legs (base) with the other.


2. Don’t touch the lenses with your fingers. The oil on your fingers will smudge and etch the lenses. Use an optical wipe if you must clean the lenses. Steer clear of toilet paper and paper towels – they will scratch your lenses.


3. When you’re done with your scope for the day, reset it so that it’s on the lowest power of magnification and lower the stage to the lowest position. Cover it with your dust cover or place it in its case.


Preparing a Dry Mount Slide

Saturday July 31, 2010

Make sure you’ve completed the How to Use a Microscope activity before you start here!


This is simplest form of slide preparation!  All  you need to do is place it on the slide, use a coverslip (and you don’t even have to do that if it’s too bumpy), and take a look through the eyepiece.  No water, stains, or glue required.


You know that this is the mount type you need when your specimen doesn’t require water to live. Good examples of things you can try are cloth fibers (the image here is of cotton thread at 40X magnification), wool, human hair, salt, and sugar. It’s especially fun to mix up salt and sugar first, and then look at it under the scope to see if you can tell the difference.


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Preparing a Wet Mount Slide

Saturday July 31, 2010

Make sure you’ve completed the How to Use a Microscope activity before you start here!


Anytime you have a specimen that needs water to live, you’ll need to prepare a wet mount slide. This is especially useful for looking at pond water (or scum), plants, protists (single-cell animals), mold, etc. When you keep your specimen alive in their environment, you not only get to observe it, but also how it eats, lives, breathes, and interacts in its environment.


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Slide Preparation: Staining

Saturday July 31, 2010

Make sure you’ve completed the How to Use a Microscope and also the Wet Mount activities before you start here!


If your critter is hard to see, you can use a dye to bring out the cell structure and make it easier to view.  There are lots of different types of stains, depending on what you’re looking at.


The procedure is simple, although kids will probably stain not only their specimens, but the table and their fingers, too.  Protect your surfaces with a plastic tablecloth and use gloves if you want to.


We’re going to use an iodine stain, which is used in chemistry as an indicator (it turns dark blue) for starch. This makes iodine a good choice when looking at plants. You can also use Lugol’s Stain, which also reacts with starch and will turn your specimen black to make the cell nuclei visible. Methylene blue is a good choice for looking at animal cells, blood, and tissues.


In addition to your specimen, you’ll need to get out your slides, microscope, cover slips, eye dropper, tweezers, iodine (you can use regular, non-clear iodine from the drug store), and a scrap of onion. If you can find an elodea leaf, add it to your pile (check with your local garden store). Here’s what you do:


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Slide Preparation: Heat Fixes

Saturday July 31, 2010

Make sure you’ve completed the How to Use a Microscope and also the Wet Mount and Staining activities before you start here!


If you tried looking at animal cells already, you know that they wiggle and squirm all over the place. And if you tried looking when using the staining technique, you know it only makes things worse.


The heat fix technique is the one you want to use to nail your specimen to the slide and also stain it to bring out the cell structure and nuclei. This is the way scientists can look at things like bacteria.


You’re going to need your microscope, slides, cover slips, eyedropper, toothpicks or tweezers, candle and matches (with adult help), stain (you can use regular iodine or Lugol’s Stain), sugar, yeast, and a container to mix your specimen in. Here’s what you do:


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Microscopes and Telescopes

Wednesday February 3, 2010

Hans Lippershey was the first to peek through his invention of the refractor telescope in 1608, followed closely by Galileo (although Galileo used his telescope for astronomy and Lippershey’s was used for military purposes).  Their telescopes used both convex and concave lenses.

A few years later, Kepler swung into the field and added his own ideas: he used two convex lenses (just like the ones in a hand-held magnifier), and his design the one we still use today. We're going to make a simple microscope and telescope using two lenses, the same way Kepler did.  Only our lenses today are much better quality than the ones he had back then!

You can tell a convex from a concave lens by running your fingers gently over the surface – do you feel a “bump” in the middle of your hand magnifying lens?  You can also gently lay the edge of a business card (which is very straight and softer than a ruler) on the lens to see how it doesn't lay flat against the lens.

Your magnifier has a convex lens – meaning the glass (or plastic) is thicker in the center than around the edges.  The image here shows how a convex lens can turn light to a new direction using refraction. You can read more about refraction here.

A microscope is very similar to the refractor telescope with one simple difference – where you place the focus point.  Instead of bombarding you with words, let’s make a microscope right now so you can see for yourself how it all works together. Are you ready?

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Laser Microscope

Wednesday February 3, 2010

Did you know that you can use a laser to see tiny paramecia in pond water? We’re going to build a simple laser microscope that will shine through a single drop of water and project shadows on a wall or ceiling for us to study.


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