Your children may have declared, “It’s summer!” if they have noticed the rising air temperatures as measured with a thermometer or as sensed in a relative way (freezing-cold-chilly-cool-warm-warmer-hot-really really hot). Planting in an outside garden or pot is another marker of summer, as is the opening of outdoor public swimming pools the weekend before Memorial Day. In the northern hemisphere, meteorological summer includes June, July, and August; meteorological fall includes September, October, and November; meteorological winter includes December, January, and February; and meteorological spring includes March, April, and May.
The season of summer may have arrived, as defined by hot weather, but the astronomical season of summer won’t begin until about 6 AM Eastern time (10 AM in UTC—Coordinated Universal Time) on June 21, known as the summer solstice, or the longest day of the year. Occasionally children (and even adults) will get into a dispute about when summer truly begins. You can ask, “What information or data will help us decide when summer begins?”
For information on the astronomical seasons, see the National Centers for Environmental Information, part of the National Oceanic and Atmospheric Administration. The astronomical seasons are based on the position of Earth in relation to the sun, whereas the meteorological seasons are based on the annual temperature cycle. Refresh your understanding of the cause of seasonal changes by reading the explanation on the NASA Space Place. Then use the activities in these two columns published in the NSTA journal, Science and Children, to model the cause of seasons for yourself:
Science 101: What causes the seasons? by William C. Richardson. January 2007. Science and Children. 44(5): 54-57
Science Shorts: The Reasons for the Seasons by Julie Lee Lambert and Suzanne Smith Sundburg. April/May 2010. Science and Children. 47(8): 67-70
If a child says, “It’s hot because the Earth is closer to the Sun in summer,” you can answer, “Summer temperatures are hotter than winter because the Sun’s rays hit this part of Earth more directly in summer than in winter.” Children (and adults) experience natural phenomena and may wonder about those experiences even if we can’t understand them. Fully understanding the Sun-Earth (and Moon) system, including seasons, is a middle school expectation in the Next Generation Science Standards (MS-ESS1-1). While first graders may be expected to “Make observations at different times of year to relate the amount of daylight to the time of year” (NGSS 1-ESS1-2), fifth graders “Represent data in graphical displays to reveal patterns of daily changes in length and direction of shadows, day and night, and the seasonal appearance of some stars in the night sky” (NGSS 5-ESS1-2) but they are not expected to understand the causes of seasons.
Early experiences and investigations that support later understanding of the Sun-Earth-moon system include:
- manipulating objects and light sources to create shadows (NGSS 1-PS4-3);
- looking at the Moon using binoculars when it is visible in the day or night;
- making observations to determine the effect of sunlight on Earth’s surface (NGSS K-PS3-1);
- noticing that when a light is shone on an object, the object casts a shadow and the side of the object away from the light source is in shadow;
- drawing shadows to notice its relationship to a light source; and
- observing to notice any pattern in the apparent paths of the Sun across the sky. Over a period of months, does sunlight always shine in the same place every day when observed at a particular time? The Science in PreK site from the Smithsonian National Air and Space Museum recommends: “Use language that is accurate but not complicated, such as “The Sun appears to move across the sky,” not to be confused with “The Sun moves across the sky.””
These experiences will prepare children to make sense of the apparent shape of the Moon, the phenomena of solar and lunar eclipses, and begin to understand the crosscutting concept of patterns—patterns can be used to identify cause-and-effect relationships—as it relates to the Earth-Sun-Moon system and seasons on Earth.
Resources for these kinds of early explorations
Science in PreK from the Smithsonian National Air and Space Museum: The Science of Light and Shadows
The Moon in Children’s Literature by Kathy Cabe Trundle and Thomas H.Troland. 2005. Science and Children. 43(2): 40-43
The Early Years columns:
December 2017 The Early Years: Using the 5Es to Teach Seasonal Changes. Using a thermometer to investigate and document seasonal changes in the local environment. Science and Children. 55(4): 18-19.
December 2015 The Early Years: The Sun-Earth System. Measuring children’s shadows at two different times of the day. Science and Children. 53(4): 22-23
January 2012. The Early Years: Seeing the Moon. Looking at the Moon, and modeling impact craters. Science and Children 49(5): 26-27.
December 2009 The Early Years: Paths of Light. Using a mirror in an open-ended exploration of light and predicting where light will be reflected. Science and Children. 47(4): 17-18.
March 2009. The Early Years: Does Light Go Through It?. Using light to explore transparent, translucent, and opaque materials. Science and Children. 46(7): 16-18.
March 2007. The Early Years: The Sun’s Energy. Growing plants in sunlight and without light, playing with light and shadow, and making “sun prints.” Science and Children. 44(7): 18-20.
January 2007. The Early Years: Light Foundations. Exploring the path of light. Science and Children. 44(5): 16-18