Jumping spider

The following photo shows a tiny spider carcass (~3/16″ long) that was inside an exuvia (~1 3/4” long) from a Common Green Darner dragonfly (Anax junius). The exuvia was collected on 17 June 2021 from a small pond in Prince William County, Virginia USA. I discovered the spider long afterward — too late to save its life.

17 JUN 2021 | PNC. Wm. County, VA | Jumping spider

Thanks to Eva Weiderman and Joseph Girgente — members of the “Odonate Larvae and Exuviae” Facebook group — for their help in identifying the specimen as a jumping spider, Family Saticidae.

Salticidae is one of several families of spiders with eight (8) eyes. My take-away from reading the reference on BugGuide entitled “Spider Eye Arrangements” is identification of this specimen to the genus and species level is challenging at best and impossible at worst.

In contrast, it’s well known that spiders use odonate exuviae for shelter. I wish the jumping spider had come out of its most excellent hidey-hole sooner!

17 JUN 2021 | PNC. Wm. County, VA | Anax junius exuvia

Related Resources

• Spider Eye Arrangements, by BugGuide. See Family Salticidae.
• Nature Abhors a Vacuum, by Douglas Mills.
• Post update: What is it? [Anax junius exuvia, shown above.]

Tech Tips

The tiny jumping spider was photographed using a Panasonic Lumix FZ-300, Raynox DCR-250 close-up filter, Godox X2To/p flash trigger, and Godox TT685F plus Altura flash modifier. Camera settings: ISO 100 | f/7.1 | 1/60 s | 56.9mm (316mm, 35mm equivalent).

“Raynox DCR-250 close-up filter” is a blog post in which I provide more information about how I use the Raynox with my Panasonic Lumix superzoom bridge cameras.

Copyright © 2022 Walter Sanford. All rights reserved.

Can “Panasonic Image App” for iOS run on a MacBook Air?

I read a recent article from Macworld entitled “How to run your favorite iPhone and iPad apps on an M1 Mac.” Naturally I wondered whether the “Panasonic Image App” for iOS would run on my MacBook Air (13″, M1, 2020). I’m pleased to report it works!

I followed the directions in the Macworld article and downloaded/installed the Panasonic Image App from the Mac App Store, shown on the left in the following screen capture from my MacBook Air.

Next, I opened the app. Notice the “Home” screen on my MacBook Air is almost identical to the “Home” screen on my Apple iPad mini 6. I clicked on the “Wi-Fi” button.

Then I looked under Settings/Wi-Fi (on my MacBook Air) for an access point to connect with the camera.

After the Wi-Fi connection was established successfully, I clicked on the “Remote operation” button on the “Home” screen and voilà, the “Live Control” panel appeared on-screen.

I wanted to see a larger view of the window, but the app doesn’t allow the user to click-and-drag in order to resize the smallish window. No problem. I clicked the green dot in the Menu Bar and the app filled the screen!

I tested a few camera functions. In particular, I changed the aperture and shutter speed and recorded a few photos. There was noticeable lag when I moved the tripod head to change the camera view, but it’s not something with which you can’t live.

When I minimized the app in order to check my folder of screen captures, that resulted in the unexpected loss of the Wi-Fi connection.

A few surprises might be expected given the disclaimer for “Panasonic Image App” that appears on the Mac App Store: “Designed for iPad. Not verified for MacOS.” From my proof-of-concept testing, I can verify the app runs on my MacBook Air and almost everything I tried works.

I really like being able to see a larger display of the “Live Control” window on my MacBook Air than on my iPad mini. Still wireless; still portable, with a larger display. In my opinion. that’s a win-win!

Related Resource: How to run your favorite iPhone and iPad apps on an M1 Mac, by Roman Loyola, Senior Editor, Macworld.

Copyright © 2022 Walter Sanford. All rights reserved.

Panasonic Image App

The Panasonic Image App enables wireless tethering of select Panasonic digital cameras with smart phones and tablets. The free app is available for both Apple iOS and Android devices.

The app works well when it’s used in a way that’s as simple and straightforward as possible — try to make all or almost all camera settings before starting the Wi-Fi connection (such as P, A, S, M), and limit the number of settings changes made using the app. Otherwise, there seems to be a risk of losing the Wi-Fi connection, although if that happens, it’s easy to reestablish the connection. Hey, there’s a reason many professional photographers prefer using a cable for tethering!

You can control the camera directly while using the app, but I don’t recommend it. In my limited experience using the app, I noticed this can result in the unexpected loss of the Wi-Fi connection.

Home

I highly recommend following Graham Houghton’s excellent directions for connecting the camera and iOS device. Regular readers of my blog might remember I reprogrammed the Fn2 button on my FZ300, so the way I start Wi-Fi is different than the procedure Graham describes in his YouTube video.

After a Wi-Fi connection is established between my Panasonic Lumix DMC-FZ300 superzoom bridge camera and my Apple iPad mini 6, the “Home” screen appears in “Panasonic Image App.” Tap the “Remote operation” button.

Live Control

The following annotated screen capture shows the “Live Control” panel. The function of all of the buttons in the panel is labeled in red text except for ISO, but we know what that means, right?

The live view window (left side of panel) shows the camera settings across the top and bottom of the window. Tap the “DISP.” to toggle this information on/off.

Top, from left-to-right: Program mode; Standard photo style plus modifications; no flash; video settings; settings for picture size and quality; AFS (focus mode, single point); and AF Macro mode as indicated by the AF-flower(icon).

Bottom, from left-to-right: Metering Mode (single point); aperture f/2.8; shutter speed 2.5″; exposure meter; and White Balance (flash).

Tap the Program Shift button (P/double-headed arrow icon) in order to change settings in Program Mode. The icon that appears for this button varies depending upon the camera mode. For example, the icon changes to “F/SS” when the camera is set for Manual Mode, as shown in the next screen capture.

The following image shows the camera set for Custom setting C1 in Manual Mode.

Tap the “F/SS” button (shown above) and a menu appears to set the aperture (F) and shutter speed (SS), as shown below. Press the go-back icon to return to the “Live Control” panel.

Notice the up/down buttons for MF (Manual Focus) on the “Live Control” panel. I need to explore this feature further. I’m hoping this implementation of Manual Focus is better than the one featured on the FZ300. In my opinion, the implementation of Manual Focus on the FZ150 is far superior to the FZ300. Hey Panasonic, are you listening?

Press the “Q.MENU” button in the “Live Control” panel in order to see the “Recording Settings” panel.

“Jump Snap” — one of the most mysterious buttons on the “Live Control” panel — is explained in the section entitled “Taking pictures mid-jump” on the following Web page: Image App (iOS) – Digital Camera.

Playback

Tap the “Play back” button, located along the bottom of the screen, in order see all of the photos and videos saved to the camera memory card.

Tap the “Menu” button, located along the bottom of the screen, in order to access “Playback settings.”

“Live Control Settings” and “Help” (shown above) might be worth a look as well, although I don’t recall exploring those Menu items.

Related Resources

• Demonstrating the Panasonic Image App on an IOS device, by Graham Houghton (23:05). See also “Demonstrating the Panasonic Image App on an Android device,” by Graham Houghton (19:38).
• Panasonic Basic Operating Instructions, Digital Camera, Model No. DMC-FZ300. See the section entitled “Wi-Fi,” pp. 41-45.
• Remote control recording [tap the “Live Control” button, located along the bottom of the screen]
• Image App (iOS) – Digital Camera [This page includes a warning for app users: “Since Wi-Fi connection drains battery quickly it is better to recharge before use when power is low.” I recommend using either an internal or external continuous power source for the FZ300.]
• Adding location information from smartphone onto digital camera images (Geotagging) [see “Home” screen]
• Join Snap Movies [see “Home” screen]
• Editing still pictures on Photo Collage function [see “Home” screen]
• Saving digital camera images on smartphone, sending them to websites, sharing them with other devices
• Playing back images on digital camera
• About menu screen [tap the “Menu” button, located along the bottom of the screen]

Copyright © 2022 Walter Sanford. All rights reserved.

Custom settings: Panasonic Lumix DMC-FZ300

I prefer to use a combination of camera settings that I call “set it and forget it,” that is, select settings that work for most subjects in most lighting conditions, enabling me to focus on the subject rather than futzing around with camera settings.

Wouldn’t it be convenient if there were a way to save a few of these setups for fast recall whenever you want? Turns out the Panasonic Lumix DMC-FZ300 superzoom bridge camera features three Custom settings: C1; C2; and C3.

The preceding image shows the camera settings for C1: “M” (Manual Exposure Mode); “Macro Mode,” as indicated by the AF-flower(icon); ISO set for either Auto (ISO limit of 400) or 100, not shown; f/7.1; shutter speed 1/640 s; and 0 ev.

Editor’s Notes: Although you might be fooled into thinking the setting for exposure compensation (ev) is “-3,” it’s actually “0.” In this case the camera display is telling you the photo is underexposed by at least three stops. Remember that ev doesn’t work in Manual Exposure Mode.

WB (White Balance) is set for flash. Notice the flash icon (located along the top of the screen, to the right of “STD.”) indicates no flash — this icon changes when either the pop-up flash is opened or an external flash unit/flash trigger is mounted on the hotshoe of the camera.

The white square in the lower-right corner of the LCD is where the histogram is shown. In this case, the histogram is simply a vertical yellow line along the left side of the square indicating the camera “sees” only blacks.

Remember all of the camera settings that I made by drilling down into the menus? All of those settings are included in the Custom settings too.

My preferred settings for C2 and C3 are the same with the exception of shutter speed: C2 = 1/800 s; and C3 = 1/1000 s.

How to save and use Custom settings

Let’s say you’d like to save a Custom setting using Aperture priority mode. Set the Mode dial to “A” and make all of the camera settings you prefer.

Next, press the Menu/Set button (on the back of the camera), select Custom (wrench-C icon), p. 1/9 Cust.Set. Mem. Use the right and left Cursor buttons to select C1, C2, or C3 and press Menu/Set. Follow the same sequence of steps in order to overwrite one of the Custom settings.

In order to shoot photos using your Custom settings, set the Mode dial to “C” to access the Custom settings saved to your camera. Use the right and left Cursor buttons to select one of three Custom settings and press the Menu/Set button.

Switch Custom settings (e.g., from C1 to C2) by pressing the Menu/Set button, then use the right and left Cursor buttons to select one of the other settings.

It’s worth noting you can change camera settings during a photo shoot without changing the Custom settings permanently.

Manual mode plus Custom settings

I prefer to shoot using Manual mode. The aperture is set for f/7.1 for greater depth of field and the shutter speed is set for ≥ 1/640 s in order to reduce camera shake.

At telephoto focal lengths, camera shake is the enemy of tack-sharp photographs. There are three ways to reduce/eliminate camera shake.

• Use the reciprocal rule. Use a fast shutter speed, equal to or greater than the reciprocal of the lens focal length (actual focal length for full-frame sensor cameras or 35mm equivalent for crop sensor cameras), in my case, usually no less than 1/640 s for a 600mm telephoto lens (35mm equivalent).
• Use a camera flash. Set the flash power ratio for 1/16 power and increase/decrease as necessary.
• Optional: Use either a monopod or tripod. Remember to turn off image stabilization when using a monopod/tripod. [Menu/Set, Rec, p. 7/7 = Off.]

Related Resources

• Registering your own settings ([Cust.Set Mem.])
• Recording using registered custom set
• Lessons learned: How to use a superzoom camera to shoot insect photos
• DMC-FZ150 versus DMC-FZ300

Copyright © 2022 Walter Sanford. All rights reserved.

Camera settings: Panasonic Lumix DMC-FZ300

Here is a list of the current Menu settings for my Panasonic Lumix DMC-FZ300 superzoom bridge camera. This blog post is the companion post for “Programmable function buttons.” I think it might be easier to understand my rationale for reprogramming the function buttons in light of the Menu settings I use.

Settings that appear in green text are ones that I think are critical for my needs. Settings shown with an orange question mark (?) means either I don’t use that function or I don’t understand that specific camera function. Some settings are grayed out on my camera and are labeled as such in the following list. Finally, there are a few notes to myself (purple text) regarding settings changes to consider.

Rec (camera icon) = 7 pages

p. 1/7

• Photo Style = Standard
• Filter Settings = No Effect
• Aspect Ratio = 4:3
• Picture Size = L 12M
• Quality = RAW plus Fine JPG

p. 2/7

• AFS/AFF = AFS
• Metering Mode = spot metering
• Burst Rate = H
• 4K Photo = 4K Burst
• Auto Bracket = Single/Burst Settings = Burst; Step 5 1/3; Sequence 0/-/+

p. 3/7

• Self Timer = 10 s
• Highlight Shadow = ?
• i.Dynamic = Off
• i.Resolution = Off
• Post Focus = Off ← Fn4 button

p. 4/7

• Handheld Night Shot = Off [grayed out]
• iHDR = Off [grayed out]
• HDR = Off [grayed out]
• Multi Exp. = ?
• Time Lapse Shot = ?

p. 5/7

• Stop Motion Animation = ?
• Panorama Settings [grayed out]
• Shutter Type = MSHTR
• Flash = Firing Mode (Manual); Flash Mode (forced flash icon); Flash Synchro (1st)
• Red-Eye Removal = Off

p. 6/7

• ISO Limit Set = 400
• ISO Increments = 1/3EV
• Diffraction Compensation = Off
• i.Zoom = Off [grayed out]
• Digital Zoom = Off [grayed out]

p. 7/7

• Conversion = Off [tele and close-up accessory lenses]
• Color Space = SRGB
• Stabilizer = Operation Mode (handheld icon) ← 1 of 3 options
• Face Recognition = Off
• Profile Setup = Off

Motion Picture (video camera icon) = 1/6 pages

Note: I haven’t made many settings for this menu group … yet.

p. 1/6

• Rec Format = MP4
• Rec Quality = 1920×1080,60p

Custom (spanner tool icon/C) = 9 pages

p. 1/9

• Cust.Set Mem. = C1, C2, C3
• Silent Mode = Off
• Silent Mode = Off
• AF/AE Lock = AF-On
• AF/AE Lock Hold = Off [grayed out]
• Shutter AF = On

p. 2/9

• Half Press Release = Off
• Quick AF = Off
• Eye Sensor AF = On
• Pinpoint AF Time = MID
• Pinpoint AF Display = PIP

p. 3/9

• AF Assist Lamp = Off
• Direct Focus Area = Off ← Fn1 button
• Focus/Release Priority = Release ← Change to Focus? Research owner’s manual. *** Set to “Focus.” ***
• AF+MF = On
• MF Assist = Side Dial icon + AF Mode button icon ← ?

p. 4/9

• MF Assist Display = PIP
• MF Guide = On
• Peaking = On
• Histogram = On
• Guide Line = 9×9 grid

p. 5/9

• Center Marker = On
• Highlight = On ← over-saturated areas
• Zebra Pattern = Off
• Monochrome Live View = Off ← Fn2 button
• Constant Preview = On

6/7

• Expo. Meter = On
• Dial Guide = On
• LVF Disp.Style = Display the icons outside of the live view area
• Monitor Disp.Style = Display the icons outside of the live view area
• Monitor Info. Disp. = On

p. 7/9

• Rec Area = set for camera icon
• Remaining Disp. = set for either camera or movie
• Auto Review = 2 s
• Fn Button Set = Setting in REC mode or Setting in PLAY mode
• Side Button Setting = AF(macro icon)/Focus

p. 8/9

• Zoom Lever = ?
• Side Lever = ?
• Zoom Resume = On
• Q. Menu = Preset [default] or Custom
• Dial Set = Rotation (F/SS)

p. 9/9

• Video Button = On
• Eye Sensor = ?
• Touch Settings = Touch Screen = On; Touch Tab = On; Touch AF = AF; Touch Pad AF = Exact
• Touch Scroll = L
• Menu Guide = On

Setup (spanner tool icon) = 5 pages

Note: I haven’t made many settings for this menu group … yet.

p. 2/5

• USB Mode = Select on connection

p. 3/5

• Menu Resume = On
• Menu Information = On

p. 4/5

• Self Timer Auto Off = On ← change to OFF ?

p. 5/5

• Format [memory card]

Playback (“Play” icon) = 4 pages

Note: I haven’t made many settings for this menu group … yet.

p. 3/4

• Rotate Disp. = On

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Related Resources

• Programmable function buttons
• Panasonic Basic Operating Instructions | Digital Camera | Model No. DMC-FZ300 [PDF]
• Panasonic Owner’s Manual for advanced features | Digital Camera | Model No. DMZ-FZ300 [PDF]

Copyright © 2022 Walter Sanford. All rights reserved.

Programmable function buttons: Panasonic Lumix DMC-FZ300

I like digital cameras with programmable function buttons, such as the Panasonic Lumix DMC-FZ300 superzoom bridge camera, that enable the user to customize the camera to work better for their needs.

The FZ300 features four function buttons (e.g., Fn1) plus five more icons displayed on-screen. All nine (9) buttons are programmable. There are also four default functions around the “Cursor” button that aren’t programmable, as far as I know.

It’s worth noting there’s a non-programmable button on the side of the lens barrel that’s labeled “AF-flower(icon)/FOCUS.” The “Macro Mode” menu is shown when this button is pressed. Menu options include: AF-flower(icon); an icon for macro zoom mode (grayed out); and flower(icon)OFF. I selected the first option. This option enables me to shoot photos with the camera as close as 1 cm from the subject.

After a long period of experimentation, I settled on a configuration of the function buttons that is close to ideal for me. Just to be clear I’m talking about the four physical buttons on the camera body, not including the five on-screen icons.

Fn1 = Focus Area Set

The FZ300 features a touch screen that can cause more headache/heartache than it’s worth. Although I set my camera so that touch screen operation is enabled, I use it only when absolutely necessary. During photowalks, the touch screen is facing toward the camera body so that I don’t change settings accidentally when I look through the EVF.

In order to set the Auto Focus “Focus Area” I prefer using the “Cursor” to move the focus area around the screen rather than touching a point on the LCD screen.

Caution: There is a Menu item for “Focus Area Set.” When that menu item is selected, the default functions of the “Cursor” buttons are disabled. But when a function button is reprogrammed for “Focus Area Set” the default functions of the “Cursor” buttons are still enabled.

Note: Exposure Compensation is the default setting for Fn1. This function can be accessed quickly via the Fn3 button Q.MENU.

Fn2 = Monochrome Live View

This function is useful when using Manual Focus mode and “Peaking.” Monochrome Live View changes the display from color to black-and-white. When “Peaking” is set for High Red it’s easy to see the areas that are in focus.

Note: “Wi-Fi” is the default setting for the Fn2 button; Wi-Fi can be enabled from a Menu setting too. Since I don’t use Wi-Fi often when I’m photowalking I think it’s better to reprogram the Fn2 button. [In order to enable Wi-Fi press the Menu/Set button (on the back of the camera), select Setup (wrench-icon), p. 1/5 Wi-Fi.]

Fn3 = Q.MENU [default]

“Quick Menu” is the default setting for the Fn3 button. This menu can be used to set most frequently used camera settings.

It’s worth noting that by pressing the “Display” button on the back of the camera repeatedly, a version of the “Quick Menu” is one of several screens that can be displayed.

I prefer using the Fn3 button to access the “Quick Menu” because it’s easier to navigate using the Cursor buttons.

Fn4 = Post Focus

I usually shoot photographs using an external flash unit. “Post Focus” is a function that I don’t use often because it doesn’t work with camera flash. Click Posts tagged ‘Panasonic “Post Focus”‘ to see the results of my experimentation with this function.

I need to test “Post Focus” in bright, sunny light and would like to be able to set the camera for that function quickly so I reprogrammed the Fn4 button.

Note: LVF is the default setting for Fn4.

Cursor ↑ = ISO [default]

Cursor → = White Balance [default]

Cursor ↓ = Drive Mode (including 2 s and 10 s timers) [default]

Cursor ← = AF Mode [default]

---

Related Resources

Press the Menu/Set button (on the back of the camera), select Custom (wrench-C icon), p. 7/9 Fn Button Set. Choose Setting in REC mode and select a function button to reprogram. There are 14 pages of options from which you can select a new function to assign to a given button.

p. 1/14

• Exposure Comp. ← default setting for Fn1 button, as labeled on camera body
• Wi-Fi ← default setting for Fn2 button, as labeled on camera body
• Q.MENU
• LVF/Monitor Switch ← default setting for Fn4 button, as labeled on camera body

p. 2/14

• AE/AE LOCK
• AF-ON
• Macro Mode
• Preview

p. 3/14

• One Push AE
• Touch AE
• Level Gauge
• Focus Area Set ← reprogram Fn1 button for this function

p. 4/14

• Cursor Button Lock
• Dial Operation Switch
• Photo Style
• Filter Select

p. 5/14

• Aspect Ratio
• Picture Size
• Quality
• AFS/AFF

p. 6/14

• Metering Mode
• Burst Rate
• 4K PHOTO
• Auto Bracket

p. 7/14

• Self Timer
• Highlight Shadow
• i.Dynamic
• i.Resolution

p. 8/14

• Post Focus ← reprogram Fn4 button for this function
• HDR
• Shutter Type
• Flash Mode

p. 9/14

• Flash Adjust.
• Wireless Setup (Flash)
• i.Zoom
• Digital Zoom

p. 10/14

• Stabilizer
• Snap Movie
• Motion Pic. Set
• Picture Mode

p. 11/14

• Silent Mode
• Peaking
• Histogram
• Guide Line

p. 12/14

• Zebra Pattern
• Monochrome Live View ← reprogram Fn2 button for this function
• Rec Area
• Zoom Lever

p. 13/14

• Side Lever
• Touch Screen
• Sensitivity
• White Balance

p. 14/14

• AF Mode/MF
• Drive Mode
• Restore to Default

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See also …

• Assigning frequently used functions to the buttons (Function buttons)
• Panasonic Basic Operating Instructions | Digital Camera | Model No. DMC-FZ300 [PDF]
• Panasonic Owner’s Manual for advanced features | Digital Camera | Model No. DMZ-FZ300 [PDF]
• Camera settings: Panasonic Lumix DMC-FZ300 – the companion blog post for this one

Copyright © 2022 Walter Sanford. All rights reserved.

Video settings: Panasonic Lumix DMC-FZ300

I’m not sure, but I think the short movie featured in my last two blog posts is the first time I’ve used my Panasonic Lumix DMC-FZ300 superzoom bridge camera to record video.

Before beginning my project, I consulted Graham Houghton for expert advice regarding recommended video settings for the FZ300.

In “The Panasonic Lumix FZ300/330 Beginner’s Guide to Creating Video,” by Graham Houghton (28:51), Graham talks about “red button recording” versus “creative video mode.”

Red Button Recording

I chose “red button recording” for the simple video I wanted to create using Apple iMovie. The following settings were selected on the camera, synthesized from Graham’s recommendations in the preceding video.

• Press Menu/Set button, Motion Picture (video camera icon), p. 1/6 Rec Format → change to MP4
• Menu/Set, Motion Picture (video camera icon), p. 1/6 Rec Quality → change to FHD 28M 60p
• Menu/Set, Custom (wrench-C icon), p. 7/9 Rec Area → switch from camera icon to video icon (Note: camera format = 4×3; video format = 16×9.)

Press the red button on top of the camera body to start recording in 16:9 format; press the red button again to stop recording. It’s that simple.

Well, not quite so simple. Although the camera was mounted on a tripod, I had to use Apple iMovie to delete a couple of seconds of video at the beginning and end of the clip because of camera shake when I pressed the button to start/stop recording. I intended to use the “Panasonic Image App” for remote control of the camera but simply forgot.

Creative Video Mode

At the ~10:20 mark in the video, Graham transitions to talking about “creative video mode.” I encourage you to continue watching the video for tips related to more advanced video recording.

Related Resource

Demonstrating the Panasonic Image App on an IOS device, by Graham Houghton (23:05).

See also “Demonstrating the Panasonic Image App on an Android device,” by Graham Houghton (19:38).

Copyright © 2022 Walter Sanford. All rights reserved.

 

Post update: What is it?

The mystery item featured in my last blog post is a Christmas tree ornament hanging above a battery-powered flashlight with a low-power incandescent bulb.

Perhaps the bigger mystery is what makes the gold propeller inside the ornament spin around when the flashlight is powered-on.

Christmas tree ornament hanging above a flashlight.

Energy Transformations

When I taught 8th grade Physical Science classes, “energy transformations” was an overarching theme in one of the lab manuals for the course.

The Rayovac No. H22 Industrial Flashlight (shown above) uses two 1.5 V D-cell batteries to power a 2.4 V incandescent bulb. When the flashlight was powered-on and placed below the Christmas tree ornament, the following energy transformations occured.

potential energy → chemical energy → electrical energy →
radiant energy → thermal energy → kinetic energy

Knowing that kinetic energy can be thought of as energy of motion, the question remains: What gives the spinning propeller its kinetic energy?

Heat Rises

How many times have you heard this common misconception? “Heat,” more correctly referred to as “thermal energy,” flows from higher to lower concentration of thermal energy, regardless of directions such as up or down. So what causes the propeller to spin?

Thermal energy from the incandescent flashlight bulb causes the temperature of the air around the flashlight bulb to increase. The warm air around the bulb is less dense than the surrounding air so it rises; the rising air current causes the gold propeller inside the Christmas tree ornament to spin. It’s worth noting I removed the plastic “lens” from the face of the flashlight head so it wouldn’t block airflow from the light bulb to Christmas tree ornament.

The Backstory

The Christmas tree ornament shown above is a treasured memento from my early childhood. My parents bought two similar ornaments: one is blue with a gold propeller; the other is green with a red propeller (not shown).

One of the ornaments was a gift for my sister; the other was for me. I can’t remember which one was given to me. In my defense, that was a long time ago — I might have been as young as three or four years old when we got the ornaments. That said, I remember clearly how fascinated I was with the spinning propeller inside the ornament!

At that time, Christmas tree lights were relatively large colored incandescent bulbs that got uncomfortably warm-to-hot when powered-on. When my Christmas tree ornament was hung above one of those lights, the propeller spun much faster than it did when hanging above the smaller flashlight bulb used for my demonstration.

Related Resource: Candle Powered Carousel (1:01). My family had one of these too.

Copyright © 2022 Walter Sanford. All rights reserved.

What is it?

You like it, you love it, you can’t get enough of it. That’s right, it’s time for another exciting episode of “What is it?”

If you think you know what is shown in the preceding video (0:28), then please leave a comment. The answer will be revealed in a post update.

Tech Tip: Click on the icon for Full screen (f), located in the lower-right corner of the video frame.

Copyright © 2022 Walter Sanford. All rights reserved.

Arrowhead Spiketail (terminal appendages)

Arrowhead Spiketail dragonflies (Cordulegaster obliqua) were spotted along small streams at undisclosed locations in Fairfax County and Prince William County, Virginia USA.

Male and female Arrowhead Spiketails are similar in appearance. They can be differentiated based upon several field marks.

Male

This individual is a male, as indicated by his “indented” hind wings and terminal appendages.

07 JUL 2014 | Fairfax County | Arrowhead Spiketail (male)

Arrowhead male and female cerci are similar in appearance, and it can be challenging to see the epiproct clearly from some viewpoints. When in doubt whether an individual is male or female, look for indentations at the base of the hind wings of males.

07 JUL 2014 | Fairfax County | Arrowhead Spiketail (male)

Female

This individual is a female, as indicated by her rounded hind wings, terminal appendages, and prominent subgenital plate (ovipositor) at the tip of her abdomen.

21 MAY 2019 | PNC. Wm. County | Arrowhead Spiketail (female)

Although Arrowhead male and female cerci are similar in appearance, there is no mistaking the subgenital plate of female spiketails! It’s easy to see why “Spiketails” is the common name for Family Cordulegastridae.

21 MAY 2019 | PNC. Wm. County | Arrowhead Spiketail (female)

So the take-away is simple: If you see a subgenital plate then the individual is definitely female; if not, then it’s probably a male.

Copyright © 2022 Walter Sanford. All rights reserved.