Question

fill in the blanks with the measurements in scientific notation.

1. the earth and the moon

a. diameter

• earth: 13000 km or ____________ km
• moon: 3500 km or ____________ km

b. distance

• between earth and moon: 384000 km or ____________ km
• between earth and sun: 149600000 km or ____________ km

1. microscopic organisms and cells

a. diameter

• a red blood cell: 0.00072 cm or ____________ cm
• a bacterium: 0.00005 cm or ____________ cm
• a virus: 0.000011 cm or ____________ cm

b. the diameter of a white blood cell is about twice that of a red blood cell. its diameter is about ____________ cm.

1. electromagnetic spectrum

the wavelengths of different waves:
a. radio waves - instant communication

• from 0.001 m or __________ m to more than 100000 m or __________ m

b. visible light rays - all the colours that we can see

• from 0.00000038 m or __________ m to 0.0000007 m or __________ m

c. x - rays - penetrating radiation

• from 0.0000000003 cm or __________ cm to 0.0000003 cm or __________ cm

Explanation:

Step1: Convert Earth - moon and Earth - Sun distances to scientific notation

The Earth - moon distance of 384000 km can be written as $3.84\times10^{5}$ km. The Earth - Sun distance of 149600000 km can be written as $1.496\times10^{8}$ km. The diameter of the Earth 13000 km is $1.3\times 10^{4}$ km and the moon's diameter 3500 km is $3.5\times 10^{3}$ km.

Step2: Convert microscopic organism diameters to scientific notation

A red - blood cell diameter of 0.00072 cm is $7.2\times 10^{-4}$ cm. A bacterium diameter of 0.00005 cm is $5\times 10^{-5}$ cm. A virus diameter of 0.000011 cm is $1.1\times 10^{-5}$ cm. Since the diameter of a white - blood cell is about twice that of a red - blood cell, it is $2\times0.00072 = 0.00144$ cm or $1.44\times 10^{-3}$ cm.

Step3: Convert electromagnetic spectrum wavelengths to scientific notation

For radio waves, 0.001 m is $1\times 10^{-3}$ m and 100000 m is $1\times 10^{5}$ m. For visible light, 0.00000038 m is $3.8\times 10^{-7}$ m and 0.0000007 m is $7\times 10^{-7}$ m. For x - rays, 0.0000000003 cm is $3\times 10^{-10}$ cm and 0.0000003 cm is $3\times 10^{-7}$ cm.

Answer:

1.

• a. Earth: $1.3\times 10^{4}$; moon: $3.5\times 10^{3}$
• b. between Earth and moon: $3.84\times 10^{5}$; between Earth and Sun: $1.496\times 10^{8}$

2.

• a. a red blood cell: $7.2\times 10^{-4}$; a bacterium: $5\times 10^{-5}$; a virus: $1.1\times 10^{-5}$
• b. $1.44\times 10^{-3}$

3.

• a. radio waves: $1\times 10^{-3}$; $1\times 10^{5}$
• b. visible light rays: $3.8\times 10^{-7}$; $7\times 10^{-7}$
• c. x - rays: $3\times 10^{-10}$; $3\times 10^{-7}$