Curriculum Map 59 - BIOLOGY JUNCTION

Safety Guidelines

Safety Guidelines
All Materials © Cmassengale

Safety goggles/glasses & aprons must be worn at all times in the laboratory.
Tie back long hair & secure lose clothing.
No horseplay is allowed in the lab.
No food or drink is allowed in the laboratory.
Practice good “housekeeping” techniques. Return items to proper places in good condition. Avoid cluttering your work area.
Never use chemicals from unlabeled containers. Check each label before dispensing a chemical, & do not return a chemical to a bottle without the teacher’s permission.
Unless told otherwise, treat all chemicals as poisonous or corrosive. Wash hands immediately with plenty of water if chemical gets on them and always wash your hands before leaving lab.
No unauthorized lab work may be done, & a teacher must be present to do lab work.
Read & study each lab assignment before coming to lab. Pay attention to safety notes in the lab manual and from the instructor. Some common lab concerns:
* Never pipette by mouth
* Never use chipped or cracked glassware
* Do not heat a closed system
* Do not point heated containers at yourself or another person
* Use a fume hood for noxious fumes
* Place heated glass on wire gauze until cool
* Do not use flammable material near open flame
* Wear gloves when dispensing irritating chemicals
* Dilute concentrated acids by adding acid to water
* Turn off burners and water faucets when not in use & before leaving lab
* Only heat glassware marked Kimex or Pyrex
* Use glycerin and a twisting motion to insert glass tubing into stoppers
* Use tongs, test tube holders, or heat-resistant gloves to handle hot glassware
* Use pins to secure dissecting organisms to the dissecting tray before cutting with a scalpel
* Wash hands before and after dissecting and keep hands away from your face
Report all accidents immediately to the teacher.
Know the location and proper use of all safety equipment in the lab.
Know where all exits are from the lab.

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Seed Germination & Detergents

Detergent & Seed Germination

Introduction:

Seeds come in different sizes, shapes, and colors. Some are edible and some are not. Some seeds germinate readily while others need specific conditions to be met before they will germinate. Within every seed lives a tiny plant or embryo.The outer covering of a seed is called the seed coat. Seed coasts help protect the embryo from injury and also from drying out. Seed coats can be quite thin and soft as in beans or very thick and hard as in locust or coconut seeds. Endosperm, which is a temporary food supply, is packed around the embryo in the form of special leaves called cotyledons or seed leaves. These generally are the first parts visible when the seed germinates. Plants are classified based upon the number of seed leaves (cotyledons) in the seed. Plants such as grasses and grass relatives can be monocots, containing one cotyledon. Dicots are plants that have two cotyledons.

Seeds remain dormant or inactive until conditions are right for germination. All seeds need water, oxygen, and proper temperature in order to germinate. Some seeds require proper light also. Some germinate better in full light while other require darkness to germinate.When a seed is exposed to the proper conditions, water and oxygen are taken in through the seed coat. The embryo’s cells start to enlarge and the seed coat breaks open and root or radicle emerges first, followed by the shoot or plumule which contains the leaves and stem.

Many factors contribute to poor germination. Over-watering results in a lack of proper oxygen levels. Planting seeds to too deep results in the seed using up all of its stored energy before reaching the soil surface, and dry conditions result in the lack of sufficient moisture to start and sustain the germination process.

Objective:

The students will be able to describe how some environmental factors affect seed germination.

Materials:

Masking tape, Scissors, 3 ziplock bags, Marker, Forceps, Paper Towels, Metric Ruler, 3 colored pencils, 25 seeds, distilled water, 50 ml graduated, 1% detergent solution, 10% detergent solution, graph paper

Procedure:

Label the 3 zip lock bags: Control, 1% Solution and, 10% Solution.
Cut 6 square pieces of paper toweling to fit each bag.
Place 2 squares in each bag.
Distribute 6 seeds on each side of the paper towel between the plastic and towel.
In the control bag add 25 ml of distilled water completely moistening the paper towel.
In the 1% solution bag add 25 ml of 1% detergent solution making sure to completely moisten the towel.
Do the same to the 10% solution bag by adding 25 ml of 10% detergent solution.
Make sure all bags are sealed tightly.
Place the bags in a dark warm place designated by the instructor.
Write a hypothesis predicting the results of the experiment.
Examine the bags daily for 5 days. Record any changes that might have occurred. If the roots is visible the seed is considered germinated.
Record your date in the table below.
Do not allow your towels to dry out. Moisten each bag with the appropriate solutions in equal amounts.
Measure the root growth of each seed daily from the time it appeared.
Graph the data from the table using the colored pencils to represent each of the zip lock bags.

Number of Seeds Germinated

Day	Control	1% Detergent Solution	10% Detergent Solution
1
2
3
4
5

Average Growth of Germinating Seeds(mm)

Day	Control	1% Detergent Solution	10% Detergent Solution
1
2
3
4
5

Graph Title: ________________________________________

Analysis:

1. How many of the seeds germinated after 5 days in distilled water? ________. In 1% solution? _______ in 10% solution? ________.

2. Was there a difference in the number of seeds germinated?

3. In which of the three bags did seeds germinate faster?

4. What was the purpose of the control?

5. Did the detergent strength have an effect on the seed’s germination? If so What was it?

6. Was your hypothesis correct? Why or why not?

7. If it was not, what will you do now?

Scientific Equipment

Scientific Equipment All Materials © Cmassengale
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	Compound Light Microscope (LM)-used to enlarge an image		Graduated Cylinder – used to measure the volume of liquids
	Microscope Slide – supports an item being examined under the microscope		Cover slip – covers specimen on a slide
	Beaker – holds liquids while they are being stirred or heated		Test Tube Brush – used to clean test tubes
	Evaporating Dish – used for heating solids		Pinch Clamps – used to control the flow of liquids through tubing
	Funnel – assists in transferring liquids to containers with smaller openings		Striker – used to ignite a burner
	Test Tubes – holds liquids for observation or testing		Safety goggles – protects the eyes from damaging substances
	Pipet pump – dispenses known volumes of liquids		Eyedropper – used to transfer small amounts of liquids
	Forceps – used to hold or lift specimens		Magnifying glass – enlarges the image of an object
	Crucible – containers used for “strong” heating		Test Tube Rack – holds test tubes during observation or testing
	Wash Bottle – used for rinsing solids out of a container		Pipet – used for exact measurements of liquids
	Spatula – chemical spoons used to transfer solids from their original container to a scale for weighing		Wire Gauze – adds additional support for containers held on tripods or O-rings
	Crucible Tongs – used for picking up crucibles & crucible covers only		Mortar & Pestle – used to grind solids into powders
	Florence Flask – used to store liquids		Erlenmeyer Flask -used to store solutions
	Dissecting Pan – holds specimen being dissected		Test Tube Holder – holds test tubes while heating
	Electronic Balance – used for weighing substances		Bunsen Burner – heat source
	Thermometer – used to measure temperature	Stopper – used to cap flasks containing liquids
	Scalpel – used for cutting specimens being dissected		Tubing – hose used for connecting glassware
	Petri Dish – plate used to culture microorganisms		Triple Beam Balance – used for weighing substances
	O-Ring – used with ring stands to support heated vessels		Volumetric Flask – used to mix precise volumes of liquids
	Watch Glass – used on top of beakers when heating	Desiccators – used to remove moisture from substances
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Seed Plants Bi

For the Angiosperms the two variation of this basic design are seen in the two Classes (Monocots versus Dicots) (see fig. 23-2).

	MONOCOTS	DICOTS
Flower structure	arranged in group of three	arranged in groups of four or five
Leaves	narrow with parallel veins	wider with branching netlike veins
Vascular tissue	scattered vascular bundles	Ring of vascular bundles
Roots	Many smaller roots	One main taproot
Seed	One cotyledon	Two cotyledons

Scientific Laws

Scientific Laws, Hypotheses, and Theories

Scientific Theory versus “Just a theory” Layman’s term:

In layman’s terms, if something is said to be “just a theory,” it usually means that it is a mere guess, or is unproved. It might even lack credibility. But in scientific terms, a theory implies that something has been proven and is generally accepted as being true.

Scientific Meanings:

SCIENTIFIC LAW: This is a statement of fact meant to describe, in concise terms, an action or set of actions. It is generally accepted to be true and universal, and can sometimes be expressed in terms of a single mathematical equation. Scientific laws are similar to mathematical postulates. They don’t really need any complex external proofs; they are accepted at face value based upon the fact that they have always been observed to be true. Specifically, scientific laws must be simple, true, universal, and absolute. They represent the cornerstone of scientific discovery, because if a law ever did not apply, then all science based upon that law would collapse. Some scientific laws, or laws of nature, include the law of gravity, Newton’s laws of motion, the laws of thermodynamics, Boyle’s law of gases, the law of conservation of mass and energy, and Hook’s law of elasticity.

HYPOTHESIS: This is an educated guess based upon observation. It is a rational explanation of a single event or phenomenon based upon what is observed, but which has not been proved. Most hypotheses can be supported or refuted by experimentation.

THEORY: A theory is more like a scientific law than a hypothesis. A theory is an explanation of a set of related observations or events based upon proven hypotheses and verified multiple times by detached groups of researchers. One scientist cannot create a theory; he can only create a hypothesis. Theories may be expanded or modified with further scientific evidence.

Development of a Simple Theory by the Scientific Method:

Start with an observation that evokes a question: Broth spoils when I leave it out for a couple of days. Why?
Using logic and previous knowledge, state a possible answer, called a Hypothesis: Tiny organisms floating in the air must fall into the broth and start reproducing.
Perform an experiment or Test: After boiling some broth, I divide it into two containers, one covered and one not covered. I place them on the table for two days and see if one spoils. Only the uncovered broth spoiled.
Then publish your findings in a peer-reviewed journal. Publication: “Only broth that is exposed to the air after two days tended to spoil. The covered specimen did not.”
Other scientists read about your experiment and try to duplicate it. Verification: Every scientist who tries your experiment comes up with the same results. So they try other methods to make sure your experiment was measuring what it was supposed to. Again, they get the same results every time.
In time, and if experiments continue to support your hypothesis, it becomes a Theory: Microorganisms from the air cause broth to spoil.

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