Water in Carrot Lab

 

How Much Water is in a carrot?

 

Introduction:

Life exists on Earth because of the abundance of liquid water. Water makes up anywhere from 70 to 90% of the body weight of living things. Living things are composed of atoms and molecules within aqueous solutions (solutions that have materials dissolved in water).  At most temperatures on the surface of the earth, water is a liquid. In this state, water is an excellent solvent, and because there is so much of it available on the earth’s surface, water is home (oceans, lakes and rivers) to much of life. Water has been referred to as the universal solvent. Water is also involved in many metabolic processes within organisms.

Water is a polar molecule and can bond both to itself and to other water molecules by weak attractions called hydrogen bonds. Hydrogen bonding is responsible for the unusual thermal properties of water including a high specific heat capacity and a high heat of vaporization.

Specific heat is defined as the amount of heat energy needed to raise the temperature of one gram of a substance 1°C. Since it takes much more energy that normal to break all the hydrogen bonds in liquid water, water resists rapid temperature fluctuations, adding stability to earth’s environments where liquid water is plentiful.

The heat of vaporization is defined as the energy needed to change the phase of a liquid to a gas. Again, because of the number and relative strength of water’s hydrogen bonds, it takes a great deal of energy to break a molecule free of its liquid partners. Heat of vaporization causes a cooling effect because as the warmer molecules evaporate from your skin they take the heat energy with them, leaving you cooler.

Objective:

Students will design and conduct an experiment to determine the amount of water present in a carrot.

Materials:

Some materials that will be available for you to use are plates, vegetable peelers, knives, graters, knee-hi stockings, foil, microwave, blow dryers, plastic bags, and paper towels.  Any other materials you use must be approved by the teacher first (No dehydrators!).

Procedure:

  1. Begin by weighing and recording the mass of the carrot.
  2. Estimate the water content present in your carrot.
  3. Develop a hypothesis for the amount of water in a carrot.
  4. Write the materials needed and procedure you will be using to extract the water.
  5. After having your hypothesis and procedure approved by the teacher, conduct the experiment.
  6. Be sure to include an introduction, procedure, data, data analysis, and a conclusion in your lab report.

 

Properties of Living Things

 

Properties of Living things

 

 

·        Early Views of life

o       Vitalism:

§        Life was generated by a objects acquisition of “Ethers” which would manifest animate it.

§        Led to idea of spontaneous generation

·        Flies came from dead animals

·        Mice came from Hay

§        Idea was challenged by scientist Francesco Redi in 1698.

·        Designed an experiment where 3 jars contained meat.

o       One Jar contained meat and had an open top which would allow the passage of “ethers” and flies. (maggots would appear on the meat)

 

o       The second jar was covered with an airtight lid allowing the passage of neither “ethers” or flies. (no maggots would appear on the meat)

 

o       The third was covered by a screen allowing passage of “ethers”, but not flies. (no maggots would appear on meat)

Setup 1              Setup 2           Setup 3

 

o       Since the third setup would theoretically allow the passage of “ethers”, but no maggots appeared, it was implied that flies were the source of the maggots.

 

·        Led to the theory of Biogenesis

o       All life comes from preexisting life

 

PROPERTIES of LIFE

 

1. Be made of Cells.

·        The Cell is the basic unit of life

·        Is self contained and possesses a barrier (membrane) which separates itself from the environment.

·        Two types of organisms.

·        Unicellular – One celled organism (Uni=1)

·        Multicellular – Many cells (Multi=”many”)

 

2. Living Things must Reproduce.

·        Must be able to create more of it’s own kind

·        Two types of reproduction:

·        Sexual – Two parent organisms combine genetic material to produce the offspring.

·        Asexual – When a single organism can divide or “bud” to create it’s offspring without another of it’s species.

 

3. Living things must Have DNA.

·        (Universal Genetic Code?)

 

4. Living things must Grow & Develop.

·        Growth refers to two processes.

·        Increase in the number of cells.

·        Increase in the size of cells.

·        Development refers to changes in the organism which occur through it’s life-span.

·        Includes cell differentiation.

·        Includes organ development

·        Includes aging & death.

 

 

5. Living things obtain & use energy.

·        Energy is used by all living things for growth, development & reproduction.

·        Life processes which result in “building” the organism ia known as Anabolism.

·        Life process where energy is extracted by “breaking-down” substances is called Catabolism.

 

6.  Living things must Respond (or react) to their environment in some way.

·        Something which causes an organism to react is known as a Stimulus (stimuli).

·        The ability of an organism to react is called Irritability.

·        Most responses are geared for maintaining Homeostasis.

·        Homeostasis is a process where an organism maintains a stable internal environment so life can continue.

·        Some examples include temperature, pH, and water content of the cell.

 

7. Must Maintain homeostasis.

·        Internal stable set of internal conditions allowing the chemical reactions of life to occur.