Activity Book 6: Answer Key

It All Adds Up!

1. a) 195 litres each day. 1,365 litres each week

1. b) 35 litres each day. 245 litres each week

2. 15 litres

3. 25 litres

4. 15 litres

 

UV Radiation and Clouds

UV Index Adjustment for Cloud and Precipitation
Type Factor % UV
Scattered Clouds 1.1 +10% (transmitted)
Hazy 0.9 -10% (absorbed)
Mainly cloudy with/without precipitation 0.7 -30% (absorbed)
Cloudy 0.6 -40% (absorbed)
Cloudy with/without precipitation 0.4 -60% (absorbed)
Overcast 0.3 -70% (absorbed)
Heavily overcast with/without rain/drizzle 0.2 -80% (absorbed)

1. Clouds can have a marked impact on the amount of UV that reaches the Earth's surface; generally, thick clouds reflect and absorb more UV than thin cloud cover.

2. UV radiation is absorbed and scattered on water vapour and aerosols and this leads to decreasing of the UV irradiance. UV can pass through thin clouds. However, sides of clouds can also reflect UV and focus solar energy and can increase the amount received at the Earth's surface in some situations.

Periodic Table Scavenger Hunt

1. Hydrogen

2. Lithium

3. Carbon

4. Nitrogen

5. Teflon

6. Potassium

7. Titanium

8. Gold

9. Iron

Science Aboard the ISS

(1) Vegetable juice

  • Decantation: No significant phase separation over the short term.
  • Filtration: The filter contains a solid residue. The filtrate is a thin reddish liquid.
  • Centrifuging: The solid portion of the mixture ends up at the bottom of the test tube. The liquid is quite thin and reddish.

(2) 3.25% milk

  • Decantation: No phase separation.
  • Filtration: No phase separation.
  • Centrifuging: No phase separation.

(3) Vinaigrette

  • Decantation: After a certain amount of time, the oil forms a layer over the vinegar. The two components can be separated with the separating funnel.
  • Filtration: The vinegar passes through the filter and takes some oil with it. The filter captures the particles.
  • Centrifuging: Complete phase separation. The oil forms a layer over the vinegar and particles

Which of the three mixtures is a colloid?

3.25% Milk

What are the components of this mixture?

Water and fatty substances (3.25%)

Cell Structure Scavenger Hunt

  1. Chromosome
  2. Golgi apparatus
  3. Mitochondrion
  4. Ribosomes
  5. Spikes
  6. Vacuole
  7. Cell wall
  8. Smooth endoplasmic reticulum
  9. Protein coat
  10. Flagellum
  11. Cell membrane
  12. Envelope

Going South for a Tan?

Answers
Vacation Site Latitude ( ° ) Date of Overhead Sun
Montego Bay, Jamaica 18.5°N July 11
Cancun, Mexico 21.2°N June 30
Acapulco, Mexico 16.9°N July 17
Rio de Janeiro, Brazil 16.9°S Dec 23
Havana, Cuba 23.1°N June 22
San Jose, Costa Rica 9.9°N Aug 14
Ambergris Caye, Belize 18°N July 13

1. The sun is highest in the sky around noon at almost 90 degrees to the surface of the earth. At this time, UV radiation is at its highest level because the sun's rays have the least distance to travel through the atmosphere, allowing more of the UV rays to filter through. In the early morning and late afternoon, the sun's rays pass through more of the atmosphere at a sharper angle, filtering more of the UV radiation greatly reducing its intensity. Similarly, the UV rays are the strongest at the equator, where the sun is most directly overhead.

2. During summer months, the sun is higher in the sky than in winter, and the length of the day is longer, hence UV is more intense.

3. The sun will pass directly overhead at the equator twice a year. The first time this occurs is in March for the vernal equinox which signifies the start of Spring. The second time this happens is in September for the autumnal equinox which signifies the start of Fall. The following chart demonstrates the second date when the sun is overhead for places south of the Tropic of Cancer and north of the Tropic of Capricorn. i.e. June 21 (summer solstice)-July 11 (the first time the sun is overhead for Montego Bay, Jamaica) = 20 days; June 21-20 days = June 1st (the second time the sun is overhead for Montego Bay, Jamaica).

Second Date of Overhead Sun
Vacation Site Latitude ( ° ) Second Date of Overhead Sun
Montego Bay, Jamaica 18.5°N June 1
Cancun, Mexico 21.2°N June 12
Acapulco, Mexico 16.9°N May 26
Rio de Janeiro, Brazil 16.9°S Dec 19
Havana, Cuba 23.1°N June 19
San Jose, Costa Rica 9.9°N April 28
Ambergris Caye, Belize 18°N May 30

4. The sun's rays are never directly overhead in Canada as the whole country lies north of the Tropic of Cancer (23.5 °N) limit.

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