You are growing streptococcus bacteria in a petri dish. When you start your
experiment, it covers 10% of the petri dish. After 3 hours, it covers 25% of the
petri dish. If the rate of growth of the bacterial colony is proportional to its size,
how long after the beginning of the experiment will the petri dish be completely
covered?

Answers

Answer 1

Step-by-step explanation:

You’ll need a clean, microwave-safe container (a quart-sized bowl works great) to mix the agar with water and then boil it. These proportions make enough nutrient agar to prepare two Petri dishes. Stir these together well:

• ½-teaspoon agar (about 1.2 grams)

• ¼ cup (60 mL) of hot water

Bring this mixture to a boil for three minutes to completely dissolve the agar. CAUTION: Adult supervision is required to boil water. If you are using a microwave oven to boil the mixture, be careful not to let it boil over. The mixture should be clear with no particles floating in it after boiling.

Remove the mixture from the microwave and allow it to cool for 3 to 5 minutes before moving on to the next step.

Take the lid off of the Petri dish (the lid is larger than the dish) and carefully cover the bottom-half of the Petri dish with warm  nutrient agar mixture.

Loosely cover the bottom portion (set the lid ajar so excess moisture can escape) and allow the mixture to cool and harden for at least an hour.

It’s time to collect some bacteria on the end of a cotton swab! The classic test is to roll a clean cotton swab in your mouth and then to lightly draw a squiggle with it on the gelled agar. However, many people like to test something even more gross like the keys on a computer, a cell phone case, the pump handle of a soap dispenser, or the TV remote control. Unless someone recently cleaned the buttons on the remote, you may be seeing some real goobers in a short time. Dampen a cotton swab and roll it in your fingers as you pull it across the surface of your choice.

Lift the lid off the Petri dish and LIGHTLY draw a squiggly line in the agar with the end of the cotton swab. Roll the swab in your fingers as you draw the line. Replace the lid and label the dish with the date and the name of the item you tested.

Use a sanitizing wipe to thoroughly clean one of the surfaces you tested in Step 6, e.g. Cellphone

With a clean swab, redo the squiggle test in the other half of the Petri dish from Step 6 to confirm your cleaning efforts.

Before growing anything, some people place each Petri dish into a separate zipper-lock bag. Place the upside down dishes into a warm – about 98°F (37°C) is fine – and totally dark place to grow. In a closed box on a cable box is a great place. In a short time, you’ll be greeted by an amazing variety of bacteria, molds, and fungi. You likely see more and larger colonies over the next few days. You shouldn’t see too much growth where the disinfectants (hand sanitizers) were used. You might even see a “halo” around each location. This halo is called the “kill zone.” Measure and compare the size of the kill zone to determine the effectiveness of different antibacterial agents.

Remember: Do NOT open the dishes once things begin to grow. You could be culturing some serious goobers and not even know it. The comfort is that they were around you all the time anyway and now you can see them. Just be careful!

Goobers like you’re growing will often stink and make their presence known after a short time. These are not toys or curiosities you’re growing. Proper disposal is essential for both safety and sanitation. Seal all the Petri dishes into larger zipper-lock plastic bags. You can add a generous shot of chlorine bleach to the bag before sealing it to add another level of destruction. Remember: do NOT open the zipper-lock bags… ever! When you’re finished analyzing the cultures, dispose of the entire sealed bag in the trash.

Golly, Mom is right! It IS important to wash your hands with soap and warm water whenever you can!


Related Questions

What is the 10th term of the sequence 12, -60, 300

Answers

Answer:

-1500

Step-by-step explanation:

the answer is 300 x - 5

I need help with this cause I wasn’t at school the day we took notes for this!!

Answers

Answer:

1. draw a parallelogram, 2. draw an isoceles triangle (a dash on 2 of the traingles lines to show its equal), 3. equilateral pentagon (a dash on all sides), 4. equilateral octogon (draw dashes on all and draw arrows on pair of parallel sides from 1 arrow to 4 arrows)

Step-by-step explanation:



(thirteen plus fourteen) minus 17​

Answers

Answer:

10

Step-by-step explanation:

Use The Pemdas Rule

(13 + 14) -17

= 27 -17

= 10

Which amount of money is closest to the 15% tip?
$3.00
$3.50
$4.00
$4.50

Answers

a 15% tip is 3.60 so 3.50 is the closest.

PLS HELP

SET UP THE EQUATION NEEDED TO SOLVE:

You place $700 in a bank to be compounded quarterly at 5%. How long will it take for the account to be worth $1500 if no additional
money is added?

A 1500 = 700 (1 + .05/4) ^4x
B 1500 = 700 (1 + .05/4) ^x
C 1500 = 700 (1 + 5/4) ^4x
D 1500 = 700 (1 + .05) ^4x

Answers

Answer:

A

Step-by-step explanation:

Compound Interest Formula :

A = P (1 + r/n)^(nt)A = amount with interestP = Principal amountr = rate (in decimal)n = amount of times compoundedt = number of years

Here, we are given :

P = 700r = 5% = 0.05n = 4 (quarterly means 4 times a year)A = 1500

Substituting the given values and taking x in place of t :

1500 = 700(1 + .05/4)^4xOption A

Find the value of x to 2dp in the equation 2x² + 5x = 9​

Answers

Answer:

where x1=-3.71 and x2=1.21

Step-by-step explanation:

first= 2x+5x-9=0, a=2,b=5,c=-9, x=

[tex] \sqrt{ {5 }^{2} } - 4 \times 2( - 9) \: over4[/tex]

second x=

[tex] \sqrt[ - 5 + ]{25 + 72} over4[/tex]

x=

[tex] \sqrt[ - 5 +4 ]{97} [/tex]

[tex] \sqrt[ - 5 - 4]{97} [/tex]

The ratio of hot dogs to hamburgers is 26:13. If the total number of lunch items is 117 how many hamburgers are there?

Answers

If the total number of lunch items is 117, there will be 39 hamburgers there

Ratio and proportion

Fractions are written as a ratio of two numbers

Given

Total items = 117

If the ratio of hot dogs to hamburgers is 26:13, then the total hamburgers that are there is given as:

Hamburgers = 13/39 * 117
Hamburgers = 39

This shows that if the total number of lunch items is 117, there will be 39 hamburgers there

Learn more on ratio here: https://brainly.com/question/2328454

#SPJ1

Which data values are outliers for this data? What is the effect of the outlier(s) on the mean? Explain.

Answers

Answer:

working on it

Step-by-step explanation:

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Answers

Answer:

the answer is 41 degrees

Just subtract

180-139

=41

(Please katie im not doing anything wrong)

Step-by-step explanation:

Answer:

∠x=41°

Step-by-step explanation:

Supplementary Angles are angles that equal 180°

1. Use the equation

∠x+∠y=180°

2. Fill in the given values

∠x+139°=180°

3. Solve

Subtract 139 from both sides

∠x+139°=180°

      -139° -139°

4. Answer

∠x=41°

Please help me with this question I’m not good at math I will give you brainless!!

Answers

Answer:

131.88

Step-by-step explanation:

perimeter = circumference

formula = c=(pi)(d)

d=42

3.14*42= 131.88

PLEASE HELP 10 MINUTES

Answers

Answer:

A

Step-by-step explanation:edg

please help pleaseeee

Answers

A) The first option

Hope this helps!

pleas help will give brainliest

Answers

Answer:
J = q x n

Step-by-step explanation:


2 = 6/3
6 =  2x 3
Simple as that
Brainliest pls !
Add friend me if you like more contents like this
Have a good day/ night :>

PLEASE HELP
USING THE LAW OF SINES

Answers

The third angle of the triangle will be ∠B = 69°.

What is an angle?

The angle is defined as the span between two intersecting lines or surfaces at or close to the point where they meet.

Given that:-

Two angles are ∠A = 43° and ∠C=68°

The third angle will be calculated as:-

∠A   + ∠C + ∠B = 180

43  +  68  +  ∠B = 180

∠B = 180 - 43 - 68

∠B = 69°

Therefore the third angle of the triangle will be ∠B = 69°.

To know more about an angle follow

https://brainly.com/question/25770607

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which scatterplot shows a nonlinear association?

Answers

Answer:

A

Step-by-step explanation:

bc it look goofy dawg. B C and D all have a pattern but A has like no attern dawg

Answer: A.

Step-by-step explanation: Because the dots are everywhere.

Here is a picture of a cube, and the net of this cube.

What is the surface area of this cube?

Enter your answer in the box.

mm²

Answers

Answer:

60 ft²

Step-by-step explanation:

in a cube all sides are congruent so you take one measurement and multiply it by the number of sides, so you do 12 × 6 equals 60.

Solve the system of equations -x + 4y = 6 and 4x – 8y = 0 by combining the equations.

(- x +4y =6)
(4x -8y =0)

-x + 4y = 6
4x - 8y = 0


Answers

Answer:

x=6 y=3

Step-by-step explanation:

Isolate x for -x+ 4y = 6: x= -6+ 4y

Substitute x = -6 + 4y

4(-6+ 4y) - 8y = 0

Simplify

-24+ 8y =0

Isolate y for -24 + 8y = 0: y =3

For x = -6+ 4y

Substitute y =3

X= -6+ 4 × 3

Simplify

X=6

The solutions to the system of equations are:

x=6 y=3

Two angles are complementary. One angle is 30 more than the other angle. Find the value
of both angles.

Answers

Answer:

α=30, β=60

Step-by-step explanation:

we have angles α and β where α + β =90 & β=α+30

this gives us a system of equations that can be solved through substitution

[tex]\alpha +\beta =90\\\beta =\alpha +30[/tex]

substitute to solve for α: α+(α+30)=90

2α+30=90

2α=60

α=30

substitute α to find β:

β=α+30

β=(30)+30 = 60

Rita rolled a die 25 times. Her results are shown in the table below:

Please help me with this, Please get answer from the table and not by the internet. Thank you! :)

Answers

Answer:

Here I see your answer

Step-by-step explanation:

Help pls (picture included)

Answers

Answer:

16x^2 - 9 = 0

(4x)^2 - 3^2 = 0

a^2 - b^2 = (a - b) (a + b)

Hence, (4x - 3) (4x + 3) = 0

Either (4x - 3) = 0 or (4x + 3) = 0

4x = 3 or 4x = -3

x = 3/4 or x = -3/4

hhhhhhelp me pleaseeeeeeeeeeeeeeeeeeee

Answers

Answer:

2/9

Step-by-step explanation:

First, square the fraction 5/6 to get 1/2 * 25/36 - 1/8. Next, multiply 1/2 and 25/36 to get 25/72. Finally, subtract 1/8 to get the answer 2/9.

Answer:

2/9

Step-by-step explanation:

=> 1/2 (5/6)^2 - 1/8

=> 1/2 (25/36) - 1/8

=> 25/72 - 1/8

=> make 1/8 to have a denominator of 72.

=> multiply the numerator and denominator by 9/9

=> 1/8 becomes 9/72

soo

=> 25/72 - 9/72

=> 16/72

^the greatest common factor is 8

=> 2/9

2/9 is your answer :)

PLEASE HELP! Observe the following quadrilaterals. They each have been labeled with a specific name. Determine if the quadrilateral was given the correct name and explain your reasoning below each quadrilateral

Answers

Rectangle:

If each angles of a quadrilateral is 90 and opposite side are equal then it is a rectangle.

Rhombus:
If in a quadrilateral, opposite angles are equal and all sides are equal, then it is a Rhombus

Answer:

Rectangle:

A rectangle has 4 interior 90° angles and 2 sets of parallel sides (11.2,11.2 and 9.6,9.6) so therefore it was correctly named

Rhombus:

Opposite angles in a rhombus are equal (102° and 102° and 78° and 78°)

and has two pairs of parallel sides; one of these pairs being diagonal lines (13.2,13.2)

What is the measure of the unknown angle?

Answers

Answer:

63

Step-by-step explanation:

a entire circle is 360⁰

so you do:

360-297

Answer:

I think its 63

Step-by-step explanation:

Sry if I am wrong. :\

I realy have been struggling to pay attention in class due to some personal reason so i would realy realy realy appreciate if someone could take a sec out of there day to help me with this... And yes i am aware i should be able to find this easy but no cap i actual cant.

Answers

Answer:

Put it after Russian

Step-by-step explanation:

Also here is some information to help you with commas:

Use a comma after an introductory clause or phrase. ...

Use a comma between all items in a series. ...

Use commas to set off nonrestrictive clauses. ...

Use a comma to set off appositives. ...

Use a comma to indicate direct address. ...

Use commas to set off direct quotations.

Answer:

ended,

Step-by-step explanation:

I believe the comma should come after the word, "ended" in the first sentence

The price of a computer component is decreasing at a rate of 15% per year. If the component cost $70 today, what will it cost in tree years?

Answers

Answer:

38.50

Step-by-step explanation:

thirty-eight dollars and fifty cents

Which of the following is not
necessarily true for all rectangles.

Answers

What are the options?

How do I solve this problem

Answers

Answer:

#9 24 T-Shirts for $168

#10 the diffirence between 30 T-Shirts and 9 T-Shirts is 147

Step-by-step explanation:

so to get the cost (c) for 1 T-Shirt you need to divide 147 by 21

147 ÷ 21 = 7

so c=7

10x7=70

70x3=210

30x7=210

so 30 shirts cost $210

and 9x7=63

so now it is time to do the rest of the math.

210

-63

147

Have a great day!

Hope this helps!

Brainliest please.

Please fully rate.

The two trolleys move at a constant velocity what is the magnitude of the acceleration of each trolleys​

Answers

Answer:

0

Step-by-step explanation:

A constant velocity means no speeding up or slowing down. So the acclereation will be 0.

What is the mean of a discrete random variable?

Answers

Answer:

Discrete probability distribution

Step-by-step explanation:

A weighted average of the possible values that random a valuable can take

Find the surface area and volume.

Answers

Answer:

surface area=2816 m² & volume =205.33m³

Step-by-step explanation:

here

diameter of base (d) -28 m

radius(r) = d/2=14 m

vertical height of cone (h)-48 m

slant height of cone (l)-50 m

surface area (TSA)-?

volume (v)-?

we know

TSA=(pie*r*l)+pie*r*r

=pie*r(l+r)

=22/7* 14(50+14)

=22*2(64)

=22*128

=2816 m²

again

v=1/3 pie*r*r

=1/3*22/7*14*14

=1/3*22*2*14

=205.33 m³

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