Why do we use more water in summer than in winter?

Grade level:  3rd – 5th grades

Skills: Line graphs

Related environmental issues: Water

The line graph below shows the average daily household water use per person in California in 2016.

Screen Shot 2017-10-03 at 11.22.18 AM

  1. In what season did a person in California use the largest amount of water?
  2. On average, a person in California used 85 gallons of water per day in 2016. In what months, did average Californians use about 85 gallons of water per day?
  3. In which month did a person in California use less amount of water per day, January or December?
  4. Between which two consecutive months did average water use increase the most?
  5. People use the largest amount of water in July and August in most of the states. Why do you think more household water is needed in those months?  Select all of the answers that apply. A) Rising outdoor water use for lawn and landscape watering B) Running the water to avoid freezing water pipes C) Increasing water use for outdoor water activities


Sources: California Water Boards, 2017. Fact Sheet (February 8, 2017)


Answer keys

  1. summer
  2. May
  3. January
  4. May and June
  5. A and C


What country sold the largest number of Electric Vehicles in 2016?

Grade level:  4th – 5th grades

Skills: Number comparison & Subtraction (Large numbers) 

Related environmental issues: Energy & Climate Change

Dyson, the UK company best known for its vacuum cleaners, recently announced its plan to build its own electric vehicles by 2020.  Conventional cars produce a lot of carbon emissions that contribute to climate change and smog.  Electric vehicles can reduce the emission because those cars are exclusively powered by electricity like iPhones. There were about 2 million electric vehicles running in the world in 2016. The table below shows the number of electric vehicles sold in five countries in 2016.

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  1. What country sold the largest number of electric vehicles in 2016?
  2. Among Japan, the United States, and Canada, which country sold the smallest number of electric vehicles in 2016?
  3. What country sold about half of the electric vehicles sold in China?
  4. How many more electric vehicles did the United Kingdom sell than Japan?

Sources: International Energy Agency, 2017. Global EV Outlook 2017 


Answer keys

  1. China
  2. Canada
  3. United States
  4. 37,912 – 24,851 = 13,061