Making a Star Clock

DSVS Spring 2011Sixth Grade

Lab 3

Important

• Please use this resource to reinforce your understanding of the lesson! Make sure you have read and understand the entire lesson prior to picking up the kit!

• We recommend that you work through the kit with your team prior to going into the classroom.

• This presentation does not contain the entire lesson—only selected experiments that may be difficult to visualize and/or understand.

Introduction• What is a star?

– A star is a massive, luminous ball of plasma that is held together by gravity. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth. Other stars are visible in the night sky, when they are not outshone by the Sun

• A long time ago, people thought that the sky was a giant ball surrounding the Earth, and that the stars were little points of light attached to the sky. Today we know that stars are huge balls of fire, just like the sun, but they appear to be small because they are so far away.

• Our solar system exists in a galaxy, the Milky Way. A galaxy is a massive, gravitationally bound system that consists of stars. The universe is made up of billions of galaxies.

Further Discussion• What are constellations? Do you know of any common ones?• Constellations are groups of stars that people have imagined to represent

various objects or gods. For example, people imagine the big dipper to be like a bowl with a handle that can be used to ladle soup or drinking water. Cassiopeia is supposed to be a queen.– Big dipper, little dipper, Cassiopeia, Orion's belt

• Have you seen any constellations in the sky before? To use the star clock that we will be making today, you have to be able to recognize some constellations.

• Before clocks were invented, people used the sun, pouring sand, and burning candles to tell time.

• Stars rise in the east and set in the west. Because we know that the earth is in constant motion, we can use the location of specific stars to tell what time it is. Those stars which appear near the North Star seem to circle around it.

Star Clocks• First, on the board, draw the big dipper,

little dipper, and Cassiopia like they are shown on the star clock. Do not draw the dotted lines in between them.

• Use a demonstration star clock to position the poster so that it shows the stars at 8PM.

• Do this by turning the inner circle until 8PM appears on the notch. Hold the star clock vertically with the current month at the top. Draw the stars on the board just as they appear on your star clock.

• Hand out the instruction sheet and have every student make a star clock, attaching the first sheet to the second with a paper fastener.

Star Clocks• Tell the students to find the current month

around the outside circle. They should put their thumbs on the current month and hold their star clocks so the current month is on top.

• Instruct them to turn only the smaller circle so that the constellations on the circle look just like the ones on the board.

• If the current month is on top, and the inner circle shows the constellations as they appear in the sky, the time can be read in the window where is says “the time is”.

• Make sure everyone is reading the same time. • Explain that the stars appear to turn in circles

around the north star, which is the middle of their star clock.

• Challenge the students to go outside after dark and try to use their star clocks. Tell them to go outside at different times to see if the constellations have moved.

Model

• To show why stars seem to go in circles, tell the students to stand up. Then tell them to imagine they are the earth, and that the ceiling is covered in stars. Now ask them to slowly turn in place while they look upwards.

• Ask them to locate where the North Star would be, which would be directly above their heads. That’s why the North Star appears stationary.