Science

Color Spectrum

Jim R 7 Comments

We have a glass prism mounted on the sill of a south wall. During the winter months it casts a spectrum on the wall on the opposite side of the room.

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As the sun descends approaching the solstice, the spectrum is cast higher on the wall. Here it is in early December very near the cold air return register.

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Today, now in mid-December, my wife noticed it was cast directly on the register grating.

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The opening for the register also returns air from a walk-in closet on the opposite side of this wall. We hurried into the darkened closet and looked on the wall opposite its register and found this. Great catch, dear.

Convex Mirror | Virtual Images

Jim R 9 Comments

I wrote about image formation using a concave mirror in previous posts. One was about virtual images. The other about real images. This time the mirror used is convex. The reflecting surface bulges outward instead of caving inward. You have seen these mirrors in use. A shiny Christmas tree ball-ornament has a convex surface. Stores can have large convex mirrors above the ends of aisles to help avoid collisions. The passenger side mirror of an automobile is slightly convex. “Objects in mirror are closer than they appear”.

We have a decorative convex mirror on our wall. Here is a view of that mirror on the left. The wall shelf unit is visible reflected in the mirror.

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Eclipse Shadow Path | 14 Oct 2023

Jim R 7 Comments

The annular eclipse of 14 Oct 2023 created a shadow upon the Earth visible from space by the GOES-16 weather satellite. It was imaged every 10 minutes in a number of wavelengths. The path of the shadow is depicted here by timeanddate dot com.

timeanddate.com

The sequence of images were gathered by the Weather Lab at College of Dupage in Illinois and compiled into this video.

Concave Mirror | Real Images

Jim R 9 Comments

Time for another physics lesson in optics. Using the small concave 3″ mirror in a previous post, light rays from a window were directed at it from about 10 meters away from across the room. I asked my assistant to stand in front of the window with her arms up so her outline was visible. The rays reflected off the concave surface of the small round mirror in the foreground and formed a small image of her in the window on a piece of white paper standing in front of the mirror. Her image on the paper card is very reduced in size and hard to see.

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ISS Space Science | 2020

Jim R 12 Comments

It has been a busy year of research aboard the International Space Station. In November 2020, we celebrated the 20th year of continuous human presence aboard the space station, which so far has hosted 242 people and more than 3,000 science experiments. During the past year, research has ranged from growing radishes in microgravity to capturing 360-degree footage of life aboard station to monitoring our planet. This research benefits people on Earth while helping prepare us to explore farther into space.