BIO152H5 Lecture Notes - Osmosis

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skywildebeest685

2 Oct 2012

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Lab report of absorption of water experiment. (1) If dry fruits are soaked in water then the weight of the dry fruits will be heavier after an hour because of osmosis. Independent variables: the 3 variables are dry fruits which include 3 black raisins and 3 brown raisins. Dependant variable: weight of all 3 dry fruits after being soaked in water. Constant variable: volume of water and constant variable would be 1 hour. Apparatus and materials: dry fruits like dates, black raisins, water, measuring cylinder, beaker and single pan weighing balance, stop clock. Weight of dry fruits after being soaked in water w2 gms. Percentage of water absorbed = w/v x 100. % of water absorbed by dry fruit = wt. of water____ x 100. Therefore dry date = 2_ x 100 = 2% 3 brown raisins = 3 x 7_ x 100 = 21 % = 7%.

Related Questions

The experiment is to measure the rate of alka-seltzer tabletdissolution. One tablet in each glass of 200 ml. of water. There isan ice-cold glass, a hot tap water glass, and a room temp. glass.These are the questions I need help with for the second part:

1. What variable was not completely controlled during theexperiment, and what could have been changed to make this variablemore constant?

2. List five questions about the rate at whichAlka-SeltzerÂ® tablets dissolve. Think about the controlledvariables. What would happen if temperature was held constant andone of the controlled variables were changed? (Hint: What otherthan water temperature could affect the rate at which the tabletsdissolve?)

3. Develop a new hypothesis basedon one of the questions. Remember that a hypothesis must betestable with empirical or measurable data.

This is what I wrote for the first part of the experiment:
What are the independent and dependent variables?

Independent- water temperature

Dependent- time of dissolution

Define at least three controlledvariables.

Amount of water in each glass

Type of glass

Alka-Seltzer tablets

State your hypothesis for todayâsexperiment as an âif/thenâ statement.

If the temperature of the water is increased then theAlka-Seltzer tablet will dissolve faster.

1. A study is being done to test the affects of habitat space onthe size of fish populations. Different sized aquariums are set upwith six goldfish in each one. Over a period of six months, thefish are fed the same type and amount of food. The aquariums areequally maintained and cleaned throughout the experiment. Thetemperature of the water is kept constant. At the end of theexperiment the number of surviving fish are surveryed

A. Independent Variable:

B. Dependent Variable:

C. Controlled Variables/Constants:

D. Experimental Controls/ Control Groups:

2. To determine if the type of agar affects bacterial growth, ascientist cultures E. coli on four different types of agar. Fivepetri dishes are set up to collect results:

One with nutrient agar and E. coli
One with mannitol-salt agar and E. coli
One with MacConkey agar and E. coli
One with LB agar and E. coli
One with nutrient agar but NO E. coli

All petri dishes received the same volume of agar, and were thesame shape and size. During the experiment, the temperature atwhich the petri dishes were stored, and at the air quality remainedthe same. After one week the amount of bacterial growth wasmeasured.

A. Independent Variable:

B. Dependent Variable:

C. Controlled Variables/ Constants:

D. Experimental Controls/ Control Groups:

taupecamel909

This is for a discussion board for my summer class:

Design an experiment that would test the hypothesis. (It might notbe a very realistic experiment, but that's OK) Use all thefollowing terms in bold to describe the experiment.

Variables, Independent or manipulated variable, dependent orresponding variable, constants, levels of the independent variable,control, repeated trials, hypothesis

Here is the hypothesis:

Predators help control the population size of herons to ensure thatthat do not overpopulate. Also, predators will play a part ineliminating members of the heron species who possess unfavorabletraits, bettering the gene pool of the species on a largerscale.

rubyrat555

BIO152H5 Lecture Notes - Osmosis

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